Forest fires are a global phenomenon and result from complex interactions between weather and climate conditions, ignition sources, and humans. Understanding these relationships will contribute to the development of management strategies for their mitigation and adaptation. In the context of climate change, fire hazard conditions are expected to increase in many regions of the world due to projected changes in climate, which include an increase in temperatures and the occurrence of more intense droughts. In Argentina, northwestern Patagonia is an area very sensitive to these changes because of its climate, vegetation, the urbanizations highly exposed to fires, and the proximity of two of the largest and oldest National Parks in the country. The main objective of this work is to analyze the possible influence of climate change on some atmospheric patterns related to fire danger in northwestern Argentine Patagonia. The data were obtained from two CMIP5 global climate models CSIRO-Mk3-6-0 and GFDL-ESM2G and the CMIP5 multimodel ensemble, in the historical experiment and two representative concentration pathways: RCP2.6 and RCP8.5. The data used in this study cover the region's fire season (FS), from September to April, and were divided into five periods of 20 years each, a historical period (1986-2005), which was compared with four future periods: near (2021-2040), medium (2041-2060), far (2061-2080) and very far (2081-2100). The statistical distribution of the monthly composite fields of the FS was studied for some of the main fire drivers: sea surface temperature in the region of the index EN3.4 (SST EN3.4), sea level pressure anomalies ​​(SLP), surface air temperature anomalies (TAS), the Antarctic Oscillation Index (AOI) and monthly accumulated precipitation (PR). In addition, the partial correlation coefficient was calculated to determine the independent contribution of each atmospheric variable to the Fire Weather Index (FWI), used as a proxy for the mean FS danger. As a result, we observed that SST EN3.4 is the only one that could indicate a reduction in fire danger in the future, although no variable presented a significant contribution to the FWI with respect to the others. In the RCP8.5 scenario, greater fire danger is projected by the TAS, the PR, the SLP, and relative by the AOI, while in the RCP2.6 scenario, only the TAS shows influence leading to an increase, which would be offset by the opposite influence of SST EN3.4 for the same periods in this scenario. In conclusion, in RCP8.5 it could be assumed that there is a trend towards an increase in fire danger given the influence in this sense of most of the variables analyzed, but not in RCP2.6 where there would be no significant changes.

How to cite: Dankiewicz, V., Rusticucci, M. M., and Collazo, S. M.: Evaluation of critical atmospheric patterns for the occurrence of forest fires in a climate change context in the northwest of Argentine Patagonia., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-610, https://doi.org/10.5194/egusphere-egu21-610, 2021.

All over the world wildfires destroy property and vegetation and can have an adverse effect on slope stability and soil erosion. Even though the number and the size of wildfires are often related to changes in land cover, population, and fire management practices, climatic and soil conditions remain the main factors influencing the extension of burnt areas. The goal of the EC Project INDECS, in which this study has been carried out, is to develop an integrated approach to produce a series of climate indicators aimed at the high priority sectors of the Global Framework for Climate Services of the World Meteorological Organization (agriculture, risk reduction, energy, health, water), with the addition of tourism. The study area is Calabria, a region of Southern Italy frequently affected by wildfires. In this research, data about the burnt areas (monthly data of extension - in hectares - and the number of fires in the period 2008-2018), provided by means of the module “Rapid Damage Assessment” (R.D.A.) of E.F.F.I.S. (European Forest Fire Information System) have been compared with the Keetch-Byram Drought Index (KBDI). This index, ranging between 0 and 203.2 (extreme dry condition of the soil), is used all over the world for monitoring and forecasting forest fires. The index was calculated with the daily rainfall and temperature data of 79 stations presenting complete and homogeneous databases. The monthly mean values were evaluated and the KBDI values were averaged for each province, given that the data of the wild fires are available for each of the five provinces of the region. The comparison results show that the peaks of the burnt areas almost always correspond with the highest of the KDBI values. Analogous results were obtained considering the number of fires. It is important to highlight that the results can be influenced by the following factors: a) the KBDI monthly mean value is evaluated by means of a database with a variable number of monthly values owing to missing data; b) the extension of the burnt areas is determined by the efficiency of the fire monitoring system and by the rapidity of first response operations; c) the RDA module database of EFFIS is referred to burnt areas with an extension greater than 30 hectares (in Europe, these fires are about 75-80% of the total fires) and does not contain differences between natural fires and human-induced fires. However, the obtained results can help to predict the impacts that tendencies of the KBDI patterns can have on the territory as an extension of burnt areas. In this way, the present study gives a useful service for agriculture and risk reduction sectors.

Acknowledgments:

The Project INDECIS is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Union (Grant 690462).

How to cite: Coscarelli, R., Aguilar, E., Vicente-Serrano, S., and Zimbo, F.: Analysis of dry conditions compared with wildfires: an application in Calabria (Southern Italy), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-466, https://doi.org/10.5194/egusphere-egu21-466, 2021.

Fire is a natural disturbance in the Neotropical savannas, and rather frequent in the relatively
dry and well-drained seasonal savannas of the Brazilian Cerrado. The neighboring Pantanal, on
the other hand, is a seasonally flooded savanna and the largest wetland in the world (≈138,000
km 2 ). Due to its wetter condition, fires in the Pantanal are much less frequent and spatially
restricted. But, given an ongoing extreme drought, the 2020’s fires in the Pantanal have been
unprecedented in extent and duration: About one third (≈45,000 km 2 ) of the area of this
important wetland has gone up in flames since last January. Regarding this historical drought,
climate change has been identified as one of the most important threats to the Pantanal.
Reductions in precipitation may cause significant disturbances in its ecological functioning,
affecting hydrological, floodplain inundation dynamics, as well as fire regime. Climate change
models from a recent study (Thielen et al. 2020, doi:10.1371/journal.pone.0227437) indicate
that, for the Pantanal, extended severe droughts are to be expected from the warming of Sea
Surface Temperatures (SST) at Northern Hemisphere oceans.
The present study analyses the spatial and temporal dynamics of precipitations during the
series 1981-2020 in the Upper Paraguay River Basin (UPRB), which comprises the Pantanal and
the neighboring Highlands, along with a co-evaluation of the SST trends at three oceanic
regions from Northern Hemisphere. Precipitation anomalies were analyzed by mean of the
Standardized Precipitation Drought Index (SPDI) based on the 1981-2010 climate normals.
Results show that for the UPRB, negative precipitation anomalies occur in pulses lasting
several years. A drought starting in 2019 has been the strongest and most extended on record,
persistently reaching the Extremely Dry condition (SPDI≤-2.0) during 2020. As early as Mar,
over 64% of the Pantanal is affected by such drought, and around 83% by Dec. For the UPRB,
four distinctive groups of subregions were identified according to their temporal dynamics of
mean SPDI values, mainly during Sep2019/Feb2020 and Mar2020/Dec2020. Here, precipitation
anomalies from southernmost subregions of the Pantanal were less intense and even not
affected by the drought.
As for SST, the Northeast Pacific region (PAC-NE) showed the most important dynamics. In this
region, SSTs have been anomalously warm since Jun 2019, with 64% of the time SSTA
surpassing the 90 th percentile: reaching the Heatwave condition. With a lead of one to two
months, PAC-NE showed the strongest (and negative) correlation with precipitation at UPRB
(r=-0.87) during Jan2019 to Dec2020. There is a significant trend for an increase in SST at the

Northeast Pacific, a trend that will certainly generate a rather continuous Heatwave in PAC-NE.
As a result, one expects an extension of the current extreme drought in the Pantanal area, at
least during 2021, and the intensification of fires with unprecedented duration and intensity,
extending now to areas historically flooded or perhumid. Concomitantly, we predict a most
definite impact on non-fire-resistant vegetation cover, as well as ecosystem functioning and
biodiversity.

How to cite: Thielen, D., Ramoni-Perazzi, P., Marquez, M., Quintero, J. I., Rojas, W., L. Puche, M., Soto-Werschitz, I. A., Thielen, K., Nunes, A., and Libonati, R.: Marine heatwaves in the dynamics of the Pantanal´s historical drought and unprecedented fires, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9268, https://doi.org/10.5194/egusphere-egu21-9268, 2021.

Fire-prone ecosystems evolved and have been managed by humans with fire for
millennia. Ignoring these socioecological realities, zero-fire policies have been
implemented in fire-prone ecosystems across the world. These inappropriate policies are
mainly originated from a forest-centered perception that fire is an essentially negative
and anthropogenic disturbance. The attempts to exclude fires have generated deleterious
ecological impacts, high fire-fighting costs, damage to properties and human lives in
grasslands, savannas and Mediterranean-type ecosystems. These zero-fire policies also
generate conflicts between governments and local communities who use fire to manage
the landscape, food production and livestock raising. Excluding fires from fire-prone
ecosystems may lead to changes ecosystem functioning and biodiversity due to woody
encroachment and/or fuel load accumulation. In regions where soil conditions allow
grasslands can be invaded by trees, changing vegetation structure and their ability to
provide ecosystem services, especially water production. In most fire-prone ecosystems,
fuel load accumulates, and the long-time unburned areas become time bombs waiting
for the next ignition source to cause disastrous wildfires. Fire bans disrupt traditional
fire management practices and commonly lead to more irresponsible uses of fire, since
local communities continue to depend on fire for their productive areas but use fire in
furtive ways to avoid criminalization. In combination with large areas with high and
homogeneous fuel loads, this leads to large, hard to control and highly impacting
wildfires, especially during late-dry season, when fires tend cause more severe impacts.
After decades under these scenarios, zero-fire policies have been substituted by active
fire management policies in fire-prone ecosystems in many countries in Africa, Latin
America, in the US and Australia, among other countries. Fire management policies
should be adapted for each regional socioecological context and allow for the active use
of fires for landscape management, biodiversity conservation and/or productive
activities. The Brazilian savanna (Cerrado) is the most biodiverse and threaten savanna
in the world and has been managed under zero-fire policy for decades. It is a tropical
humid savanna (1,500mm mean annual precipitation) where large (>10,000 hectares),
frequent (2-4 years fire interval) late-dry season wildfires are common, including in
Protect Areas (PA) dedicated to biodiversity conservation and traditional communities’
livelihoods. In 2014, a pilot Integrated Fire Management (IFM) program has been
implemented in three Cerrado PAs. The program considers local uses of fire,
implements prescribed burns and landscape management planning aiming to (i) change
the main season of burnings (from late- to early- and mid-dry season); (ii) protect fire-
sensitive vegetation, such as riparian forests, from fires; (iii) decrease firefighting costs;
(iv) reduce conflicts with local communities and (v) lower greenhouse gases emissions.
The IFM program has since been implemented in more than 30 federal PA, including
Indigenous Territories., where this approach has successfully achieved its main
objectives. The present challenge is to expand IFM actions to the state and especially
private -owned lands, which will allow for a significant change in wildfire patterns
across the whole 2 million km 2 of the Brazilian savanna.

How to cite: Schmidt, I. B.: Managing Fire to Avoid Wildfires in Fire-prone Ecosystems, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10273, https://doi.org/10.5194/egusphere-egu21-10273, 2021.

At the beginning of August 2018 Portugal experienced extreme fire prone meteorological conditions with very hot and dry air, driven by the occurrence of a severe fire event in Southern Portugal, noun as Monchique wildfire. The severe wildfire probability occurrence was re-enhanced by the substantial fuel amount accumulated since the last extreme wildfire occurred over this region in August 2003. On the 2^nd August 2018, extreme fire danger conditions were predicted for Monchique region and the fire started on the 3^rd and lasting till the 10th of August, with the evacuation of people from several villages and the associated burnt area of 27000 ha (ICNF, https://www.icnf.pt/). This event posed hard challenges on suppression activities due to its exceptional severity, related to high values of fire radiative energy released. This work aims to study the driving factors of Monchique wildfire in 2018 and assessing the usefulness of fire probabilistic products disseminated up to 72 hours in advance, as an early warning tool in fire prevention and suppression activities. The assessment of fire danger conditions was done based on ensemble forecasts fire products of the Ensemble Prediction System (EPS), provided by Copernicus Atmosphere Monitoring Service (CAMS); and based on fire danger metrics produced by Copernicus Emergency Management Service (CEMS) for the European Forest Fire Information System (EFFIS). Fire Weather Index (FWI) and Fine Fuel Moisture Code (FFMC) were selected from the Canadian Forest Fire Weather Indices System (CFFWIS) to describe the meteorological fire danger of Monchique event.

The assessment of fire severity was based on the Fire Radiative Energy (FRE) released by the fire, computed from the Fire Radiative Power (FRP) product delivered in near real-time by EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) (https://landsaf.ipma.pt/en).

FWI and FFMC ensemble results based on CAMS dataset, 24 hours before the ignition, showed Monchique region above the 95^th percentile of the ensemble, with ensemble maximum values, for both indices, being achieved on the period 6^th-9^th August 2018. FWI and FFMC, obtained from ERA5 data, registered the highest daily anomalies on the 3^rd August 2018, recording values that are classified from very high to the extreme over Monchique region. The fire severity/intensity assessment based on the FRE product showed very high amounts of energy released during this fire event, daily maximum amounts of 10000 MW during 5^th -8^th August. Total FRP (MW) and FRE (GJ) values accumulated per pixel over the duration of the event achieved maximum values of 7x10⁴ and 6x10⁴, respectively, in certain pixels, illustrating the severity of this event and the hard challenge that was developed on suppression activities by Portuguese authorities.  Therefore, obtained results show that selected products were able to properly assess fire danger and fire severity for Monchique region over those days.

Acknowledgments: This study was performed within the framework of the LSA-SAF, co-funded by EUMETSAT and was partially supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project FIRECAST (PCIF/GRF/0204/2017).

How to cite: Durao, R., Alonso, C., and Gouveia, C.: Are fire probabilistic products an effective early warning tool in the management of prevention fire activities? – the case of Monchique 2018 wildfire., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10133, https://doi.org/10.5194/egusphere-egu21-10133, 2021.

Despite  growing concerns regarding the Amazonian wildfires, the magnitude of the problem is poorly understood. In this study, we assessed the wildfire activity in the  protected natural sites (n= 428) of Bolivia, Brazil, Colombia, Ecuador, French Guyana, Guyana, Peru, Suriname, and Venezuela, encompassing an area of 1.4 million km² of the Amazon basin. A 250 m resolution spectroradiometer sensor imaging (MODIS) was used to obtain land-use/land-cover (MODIS land use land cover product) changes and derive the wildfire activity data (ignition locations and burned areas (MODIS active fire products)) from 2001 to 2018. First, we characterized the mean fire return interval, wildfire occurrence, and empiric burn probability. Then, we implemented a transmission analysis to assess the burned area from incoming fires. We used transmission analysis to characterize the land use and anthropic activities associated to fire ignition locations across the different countries. On average, 867 km ² of natural forests were burned in protected natural sites annually, and about 85 incoming fires per year from neighboring areas accounted for 10.5% (9,128 ha) of the burned area. The most affected countries were Brazil (53%), Bolivia (24%), and Venezuela (16%).Considerable amount of fire ignition points were detected in open savannas (29%) and grasslands (41%) , where the fire is periodically used to clear extensive grazing properties. The incoming fires from savannas were responsible for burning the largest forest areas within protected sites, affecting as much as 9,800 ha in a single fire event. In conclusion, we  discuss the potential implications of the main socioeconomic factors and environmental policies that could explain increasing trends of burned areas. Wildfire risk mitigation strategies include the fire ignition prevention in developed areas, fire use regulation in rural communities, increased fuels management efforts in the buffer areas surrounding natural sites, and the early detection system that may facilitate a rapid and effective fire control response. Our analysis and quantitative outcomes describing the fire activity represent a sound science-based approach for an well defined wildfire management within the protected areas of the Amazonian basin.

How to cite: Da Ponte, E., Alcasena, F., Bhagwat, T., and Hu, Z.: Assessing the wildfire activity in protected areas of the Amazon basin, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7200, https://doi.org/10.5194/egusphere-egu21-7200, 2021.

Throughout Indonesia - ecological degradation, agricultural expansion, and the digging of draining canals has compromised the integrity and functioning of large swathes of peatland forest, leaving behind a fragmented landscape of scrubland, successional forest, and newly established plantations. These landscapes are susceptible to extensive and intensive wildfires that rage out of control each year. One of the most affected regions is the ex-Mega Rice Project (EMRP) area in Central Kalimantan on the island of Borneo, where 1 million ha of peatland forest were cleared and 4000 km of canals were dug between 1996-1998, in an attempt to initiate large scale industrial rice cultivation. This led to disturbances to the underlying hydrology, the local ecology, and the ability of the local population to maintain a livelihood, who’s efforts are thwarted each year but the returning wildfires.

Directing  fire prevention and mitigation efforts requires a detailed understanding of the main drivers of fire distribution and the conditions of initiation. To this end, we have developed a fire susceptibility model using machine learning (XGBoost random forest) that characterises the relationships between key predictor variables and the distribution of historic fire locations. Using the model, we determine the relative importance of each predictor variable in controlling the initiation and spread of fires. We included land-cover classifications, a forest clearance index, vegetation indices , drought indexes, distances to infrastructure , topography, and peat depth, as well as the Oceanic Niño Index (ONI). The model was trained to separate burnt areas from not burnt areas using point samples of predictor variables taken from both, and then tested by applying the model across the entire study area for all years. The model performance consistently scores highly in both accuracy and precision across all years (>0.75 and >0.68 respectively), though recall metrics are much lower (>0.25).

Our results confirm the anthropogenic dependence of extreme fire events in the region, with the distance to settlements, and distance to canals consistently weighted as some of the most important driving factors within the model structure. In combination, the vegetation indices were the strongest indicators of fire prevalence. Ours is the first analysis in the region to encompass the full range of driving factors within a single model that captures the inter-annual variation as well as the spatial distribution of peatland fires. Our results can be used to target the root causes of fire initiation and propagation to better construct regulation and rehabilitation efforts to mitigate future wildfires.

How to cite: Horton, A., Virkki, V., Lounela, A., Miettinen, J., and Kummu, M.: Identifying key drivers of peat-fires across Kalimantan’s ex‑Mega Rice Project area using machine learning, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12237, https://doi.org/10.5194/egusphere-egu21-12237, 2021.

Abstract:  In prior published work with reconstructions of early and late 20^th century forest landscapes, we were surprised by the large amount of historical meadows, shrubfields, sparse woodlands, and bare ground (hereafter, nonforests) we observed on forest-capable biophysical settings. We also noted a trend of forest encroachment and densification in the late 20^th-century. Here, using LANDFIRE remotely sensed, existing vegetation height and cover, and environmental site potential map layers for seven western provinces--rescaled to match the grain of photogrammetric data--we quantitatively compare the area and patch size distributions of early- (E20^th), late 20^th-century (L20^th), and early 21^st-century (E21^st) nonforest conditions. Our results showed a trend of increasing nonforest area from the E20^th to E21^st-century and declining forested area in most provinces, with increases occurring primarily in the larger patch sizes. Our results coupled with other reburn modeling research suggest that extensive nonforest patchworks are intimately linked to forest landscape resilience, which is changing in uncharacteristic ways in some provinces. For example, in the Northern and Southern Cascade, and Blue Mountains provinces, we see an uncharacteristic coarsening of the grain by recent fires, while in the Upper Klamath province, we see a return to a large fire event-driven system. In a physical science sense, our results suggest that fire-prone forests -- in the largest context -- function as stored potential energy, and there is an ongoing tug-of-war waged over space and time between factors growing and removing forests. Nonforests on forest capable sites represent areas where stored potential energy has been reduced. Modern changes we observe in forested area foreshadow changes we can expect with climate warming.

How to cite: Hessburg, P.: Patch Sizes, Area, and Spatial Distribution of Nonforests Are Vital Ingredients to Fire-Adapted Western US Forests, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-743, https://doi.org/10.5194/egusphere-egu21-743, 2021.

Fire events on a landscape scale are a widespread global phenomenon that influences the interactions between atmosphere and biosphere. Global burned area (BA) products derived from satellite images are used in dynamic vegetation fire modules to estimate greenhouse gas emissions, available fuel biomass and anthropic factors driving fire spread. Fire size and shape complexity from individual fire events can provide better estimates of fuel consumption, fire intensity, post fire vegetation recovery and their effects on landscape changes to better understand regional fire dynamics. Especially in the Brazilian savannas (Cerrado), a mosaic of heterogeneous vegetation where has prevailed an official “zero-fire” policy for decades leading to an increase in large wildfires, intensified also by rapid changes of land use using fire to land clearing in agriculture and livestock purposes. In this way, we aim to assess the fire size and shape patterns in Cerrado from 2013 to 2015, identifying each fire patch event from Landsat BA product and calculating its fire features with landscape metrics. We calculated its surface area to evaluate fire size and the metrics of shape index, core area and eccentricity from an ellipse fitting from burned pixels to estimate the fire shape complexity. The study focused on 48 Landsat path/row scenes and the analysis final compared the fire features of overlapped patches between the years. The total number of coincident fire patches is higher between the years 2013 and 2015 than 2013-2014 and 2014-2015. Large fires are found in the north and east regions for all comparisons. In this region, high core area values are consistent for having large areas of burnt patches and low shape index values and more elongated patches revealed a low fire shape complexity. These results demonstrate a greater burned area in the north, where the remaining native vegetation and less fragmented landscapes allow the fire to spread, when associated with favorable meteorological conditions. However, with the implementation of a new agricultural frontier in 2015, this region is under greater anthropic pressure with positive trends to land use. In the south, the fire shapes are already more complex and smaller because they are from agricultural areas historically developed, and consequently the landscape is more fragmented. Our results demonstrate a distinct spatial pattern of fire shape and size in Cerrado related to fragmentation of landscape and fire use to land cleaning. This information can help the modelling estimates of fire spread processes driven by topography, orientation of watersheds or dominant winds at local level, contributing to understanding the feedback with land cover/use, climate and biophysical characteristics at regional level to develop strategies for fire management.

Acknowledges: J.N is funded by the 'Women in Research'-fellowship program (WWU Münster) and within the context of BIOBRAS Project “Research-based learning in neglected biodiverse ecosystems of Brazil”; funding by DAAD (number 57393735); validation dataset was performed under the Andurá project (number 441971/2018–0) funding by CNPq

How to cite: Nogueira, J., Rodrigues, J., Lehmann, J., Meyer, H., and Libonati, R.: Spatial patterns of fire patch size and shape complexity in the Brazilian savanna, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16467, https://doi.org/10.5194/egusphere-egu21-16467, 2021.

Unprecedented fire events in recent years are leading to a demand for improved understanding of how climate change is already affecting fires, and how this could change in the future. Increased fire activity in South America is one of the most concerning of all the recent events, given the potential impacts on local health and the global climate from loss of large carbon stores under future environmental change. However, due to the complexity of interactions and feedbacks, and lack of complete representation of fire biogeochemistry in many climate models, there is currently low agreement on whether climate change will cause fires to become more or less frequent in the future, and what impact this will have on ecosystems. Here we use the latest climate simulations from the UK Earth System Model UKESM1 to understand feedbacks in fire, dynamic vegetation, and terrestrial carbon stores using the fire-enabled land surface model JULES-INFERNO, taking into account future scenarios of change in emissions and land use. Based on evaluation of the modelling framework performance for the present day, we address the specific policy-relevant question: how much fire-induced carbon loss will there be over South America at different global warming levels in the future? We find that burned area and fire emissions are projected to increase in the future due to hotter and drier conditions, which leads to large reductions in carbon storage especially when combined with increasing land-use conversion. The model simulates a 38% loss of carbon at 4°C under the highest emission scenario, which could be reduced to 8% if temperature rise is limited to 1.5°C. Our results provide a critical assessment of ecosystem resilience under future climate change, and could inform the way fire and land-use is managed in the future to reduce the most deleterious impacts of climate change.

How to cite: Burton, C., Kelley, D., Jones, C., Betts, R., Cardoso, M., and Anderson, L.: South American fires and their impacts on ecosystems increase with continued emissions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6347, https://doi.org/10.5194/egusphere-egu21-6347, 2021.

Africa is the biggest continental source of biomass burning (BB) emissions. The large fluxes of chemical pollutants and aerosol emitted during intense BB events can strongly alter tropospheric chemistry and cloud dynamics and can result in widespread air pollution. Available BB emission inventories differ in terms of satellite sensor data and assumptions and methodologies used to estimate emission fluxes, and show substantial differences in emission totals and spatial and temporal patterns. The omission of small fires (<100 ha) by most satellite products is one key factor on the accuracy of the emission inventories.

The ESA Fire_CCI project has released the first burned area product for Africa from 20 m Sentinel satellite information (FireCCISFD11). Here we present new BB emission estimates for Africa based on FireCCISFD11. By resolving small fires, this inventory (Fire_CCI) yields 60 to 110% higher burning rates in 2016 than the MODIS-based products such as GFED4s, GFED4, MCD64A1 Collection 6, FireCCI51 and FINN. We perform WRF-Chem model simulation with three BB emission inventories (FINN, GFED4s and Fire_CCI) for summer 2016 corresponding with the DACCIWA aircraft campaign, which took place in June-July 2016 over Africa. We investigate the impact of uncertainties in BB emission estimates on air pollution model predictions using measurements of chemical species and aerosols from DACCIWA, NO2 and CO data from OMI and MOPITT satellites, respectively, and ground-based AOD observations from the Aeronet network. We furthermore assess the ability of the model in terms of the representation of transport of BB air masses and of the representation of chemical composition in such plumes.

How to cite: Bouarar, I., Heil, A., Deroubaix, A., Visser, A., Boersma, F., and Brasseur, G.: Uncertainties in biomass burning emission estimates and their impact on air pollution model predictions over Africa, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5812, https://doi.org/10.5194/egusphere-egu21-5812, 2021.

Poor air quality in India affects the health of millions living in one of the most populated regions in the world. Agricultural residue burning as a common way to remove crop waste and make fields for the next planting season contributes to this problem and, despite attempts to reduce agricultural fires, remains a recurring issue due to a lack of viable alternatives. As India population grows, more food production will be needed, with yet more crop residue to burn. Sustainable and economically feasible interventions are therefore needed to mitigate the impact of agricultural residue burning. To support policy-making, an adjoint modeling approach has been applied to estimate how air quality and health impacts respond to changes in specific time and location of burning, and how effective potential mitigation options might be in reducing them.

This work extends based upon these initial findings and seeks to provide a cost-benefit analysis of alternatives to agricultural residue burning using the GEOS-Chem adjoint model. With a multi-year assessment that accounts for the impact of inter-annual variability of meteorology, the public cost presented in terms of the monetary valuation of air quality damages resulting from population exposure and health impacts due to emissions of agricultural burning,  and the private returns presented in terms of the individual profit from crop cultivation for farmers in India, are quantified in order to better understand the potential trade-offs between air quality improvement and economic benefit.

The end results focusing on northwestern India during the post-monsoon rice residue burning season, where the majority of agricultural fires in India come from, show that appropriate measures, including crop diversification, agricultural mechanization and shifting the time of burning, may help avoid air quality damages from agricultural residue burning without risking the income of farmers. Proper incentive mechanisms such as subsidies for investment cost and compensation for human effort may further facilitate the best possible outcomes. These findings help inform better decision-making to mitigate the impacts of agricultural fires and reduce the uncertainties regarding sustainable agricultural practices not just for India but also for regions and countries facing similar issues.

How to cite: Lan, R., Eastham, S., Norford, L., and Barrett, S.: Cost-benefit analysis of alternatives to mitigate the air quality and health impacts from agricultural residue burning in India, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7066, https://doi.org/10.5194/egusphere-egu21-7066, 2021.

Particle and trace gas emissions can undergo rapid changes in the atmosphere as a result of evaporation, condensation, and coagulation processes that are driven by dynamics and photochemistry.  Here we analyze the fate of non-methane hydrocarbons (NMHCs) gases emitted by intense fires associated with pyroCbs towers that rise and cool rapidly and undergo relatively little dilution as they loft smoke into the upper troposphere and lower stratosphere.  We use airborne observations of plumes from the Williams Flats Fire over the continental United States taken during 2019 FIREX-AQ campaign.  Trace gas data from both fresh boundary smoke and PyroCb-lofted smoke from this fire are compared to that from smoke plumes that stayed at lower altitudes to constrain the roles of condensation, cloud processing and photochemistry in the outflow of pyroCbs.  In the pyroCb outflows we observe lower CO normalized NMHCs mixing ratios with low vapor pressure compared to the boundary layer samples while for high vapor pressure compounds there is little difference between the CO normalized NMHC mixing ratios observed in the different fresh smoke plumes.  Associated with this decrease in condensable NMHCs we find an increase in particle concentrations, specifically at large sizes (~350nm). These multiple observational facts are used to estimate the secondary organic aerosol production by NMHC condensation in pyroCb.  Further analysis of FIREX-AQ data will be used to elucidate the roles of solubility and photochemistry on SOA formation in pyroCbs. These FIREX-AQ results will be used to inform cloud resolving large eddy simulation (LES, HIGRAD) to examine deep convective fire impacts on long range smoke impacts on climate and air quality.

How to cite: Benedict, K., Gorkowski, K., Lee, J., Simpson, I., Barletta, B., Blake, D., Diskin, G., Katich, J., Schwarz, J., Reisner, J., and Dubey, M.: Evidence of secondary organic aerosols formation by non-methane hydrocarbons condensation in cold Pyro-cumulonimbus (pyroCb) outflows, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13143, https://doi.org/10.5194/egusphere-egu21-13143, 2021.

Vegetation fires – including the application of fire in land use, land-use change and uncontrolled wildfire – affect the functioning of the Earth System and impose significant threats to public health and security.  This paper presents the concept of a Vegetation Fire and Smoke Pollution Warning Advisory and Assessment System (VFSP-WAS^*). It describes the scientific rationale for the system and provides guidance for addressing the issues of vegetation fire and smoke pollution, including key research challenges. The paper  proposes the establishment of VFSP-WAS regional centers and describes  Potential examples of  this VFSP-WAS concept are described from two regions in (South-East Asia and North America) where regional centers will partner with Regional Fire Monitoring / Fire Management Resource Centers.

*) https://community.wmo.int/activity-areas/gaw/science/modelling-applications/vfsp-was 

How to cite: Baklanov, A., Chew, B. N., Frassoni, A., Gan, C., Goldammer, J. G., Keywood, M., Mangeon, S., Manseau, P. M., and Pavlovic, R.: The WMO Vegetation Fire and Smoke Pollution Warning Advisory and Assessment System (VFSP-WAS): Concept, current capabilities, research and development challenges and the way ahead, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16504, https://doi.org/10.5194/egusphere-egu21-16504, 2021.

Wildfire is the most prevalent natural disturbance in the North American boreal (BNA) forest and can cause post-fire land surface temperature change (ΔLST_fire) through biophysical processes. Fire regimes, such as fire severity, fire intensity and percentage of burned area (PBA), might affect ΔLST_fire through their impacts on post-fire vegetation damage. However, the difference of the influence of different fire regimes on the ΔLST_fire has not been quantified in previous studies, despite ongoing and projected changes in fire regimes in BNA in association with climate change. Here we employed satellite observations and a space-and-time approach to investigate diurnal ΔLST_fire one year after fire across BNA. We further examined potential impacts of three fire regimes (i.e., fire intensity, fire severity and PBA) and latitude on ΔLST_fire by simple linear regression analysis and multiple linear regression analysis in a stepwise manner. Our results demonstrated pronounced asymmetry in diurnal ΔLST_fire, characterized by daytime warming in contrast to nighttime cooling over most BNA. Such diurnal ΔLST_fire also exhibits a clear latitudinal pattern, with stronger daytime warming and nighttime cooling one year after fire in lower latitudes, whereas in high latitudes fire effects are almost neutral. Among the fire regimes, fire severity accounted for the most (43.65%) of the variation of daytime ΔLST_fire, followed by PBA (11.6%) and fire intensity (8.5%). The latitude is an important factor affecting the influence of fire regimes on daytime ΔLST_fire. The sensitivity of fire intensity and PBA impact on daytime ΔLST_fire decreases with latitude. But only fire severity had a significant effect on nighttime ΔLST_fire among three fire regimes. Our results highlight important fire regime impacts on daytime ΔLST_fire, which might play a critical role in catalyzing future boreal climate change through positive feedbacks between fire regime and post-fire surface warming.

How to cite: Zhao, J., Yue, C., Ciais, P., Hou, X., and Tian, Q.: Fire regime impacts on post-fire diurnal land surface temperature change over North American boreal forest, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10702, https://doi.org/10.5194/egusphere-egu21-10702, 2021.

The 2019/20 Australian wildfires burned the largest forested area in Australia´s recorded history, with major environmental and socio-economic consequences. These included extensive ash and soil erosion events which threatened water quality in parts on eastern Australia.  

The second largest fire was the 280,000 ha Green Wattle Creek Fire, which burned large forested areas of the Warragamba catchment. This protected catchment provides critical ecosystem services for Lake Burragorang, Australia’s largest urban supply reservoir delivering ~85 % of the water used in Greater Sydney. 

The fire caused major challenges for maintaining the supply of clean water to the Greater Sydney region (> 5 million consumers). Shortly after the fire was contained, an extreme rainfall event (up to ~276 mm in 72 h), caused extensive ash and sediment delivery into the reservoir.

Here we (i) summarise the effects of this unpreceded fire seasons on erosion and water quality in general and (ii) report on the interactions between science and land management to quantify predict and mitigate the risk to water supply for the Greater Sydney region. The latter included assessments of fire severity, ash quantities and their pollutant content using remote sensing and ground measurements, as well as the application and further development of a new modelling tool,  WEPPcloud-Wildfire Ash Transport and Risk tool (WEPPcloud-WATAR - https://wepp.cloud -). This tool allows predicting probabilities for sediment, ash and contaminant transport for different rainfall scenarios, and aided the identification of risk hotspots to focus post-fire erosion mitigation measures.  

Risk modelling, on-ground monitoring and operational mitigation measures ensured the continuity of safe water supply to Greater Sydney. This collaborative interaction between scientists and water managers, that also allowed the refinement of the model capabilities and its outputs, exemplifies the successful outcomes that can be achieved through the close collaboration between science and end-users.   

How to cite: Doerr, S. H., Neris, J., Santin, C., Lew, R., Robichaud, P. R., Elliot, W. J., Lewis, S. A., Sheridan, G., Rohlfs, A.-M., Ollivier, Q., and Oliveira, L.: The impacts of catastrophic 2019/20 Australian wildfires on erosion and water quality: the case of Sydney’s main water supply, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15880, https://doi.org/10.5194/egusphere-egu21-15880, 2021.

How to cite: Millington, J., Perkins, O., Kasoar, M., and Voulgarakis, A.: Advancing representation of anthropogenic fire in dynamic global vegetation models, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9502, https://doi.org/10.5194/egusphere-egu21-9502, 2021.

Extreme wildfire events associated with strong pyroconvection have gained the attention of the scientific community and the society in recent years. Strong convection in the fire plume can influence fire behaviour, as downdrafts can cause abrupt variations in surface wind direction and speed that can result in bursts of unexpected fire propagation. Climate change is expected to increase the length of the fire season and the extreme wildfire potential, so the risk of pyroconvection occurence might be also altered. Here, we analyse atmospheric stability and near-surface fire weather conditions in the Iberian Peninsula at the end of the 21st century to assess the projected changes in pyroconvective risk during favourable weather conditions for wildfire spread.  

How to cite: Senande-Rivera, M. and Miguez-Macho, G.: Projected changes in pyroconvective conditions in the Iberian Peninsula at the end of the 21st century, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15526, https://doi.org/10.5194/egusphere-egu21-15526, 2021.

Forest fires have always been present in Mediterranean ecosystems; as such, they constitute a major ecological and socioeconomical issue. Despite being mostly of anthropogenic origin, the influence of the recent increase in temperature and evapotranspiration is associated with an increase in the frequency and severity of wildfires in the region. Large fires are promoted by the occurrence of high temperatures and episodes of drought that may lead to total burnt areas being several times larger than the average, such as the burnt areas in Portugal in 2003 and 2005, and Greece in 2007. The fire season of 2017 in Portugal has been catastrophic by most accounts. The authorities reported more than 100 human fatalities, with about 500.000ha of estimated burnt area, which corresponds to the maximum record since 1980. 

The Land Surface Analysis Satellite Applications Facility (LSA SAF) from EUMETSAT operationally disseminates a set of fire related products for the Mediterranean region. The Fire Radiative Power product (FRP-PIXEL) is delivered in near real-time since 2004 with a 15-min temporal resolution. In this work, daily Fire Radiative Energy (FRE) is computed for the Mediterranean region. The Fire Risk Map (FRM) product combines information from the operational forecasts from ECMWF and vegetation state from SEVIRI to derive forecasts of the risk of fire for the Mediterranean region. The FRM algorithm computes the daily values of the set of components of the Canadian Forest Fire Weather Index System (CFFWIS) for Mediterranean Europe, together with levels of fire danger associated with probabilities of occurrence of fires exceeding specified magnitudes. The FRM can be an important tool to support the management of forest fires and the decision making of prescribed burning within the framework of agricultural and forest management practices.

This work aims to assess the performance of the FRM product during 2020 over the Mediterranean region using FRE estimates. In particular, we aim to evaluate if the more severe and intense fires occurred in areas of high fire risk and high probability of occurrence of extreme fires, as obtained using FRM products. This analysis is made for different countries in the Mediterranean Basin, namely Portugal, Spain, Italy, and Greece. Results reveal a good performance of FRM over the Mediterranean region during 2020; however, better results were observed for the fire season in the Iberian Peninsula than for Italy.

Acknowledgements: This study was performed within the framework of the LSA-SAF, co-funded by EUMETSAT This work was partially supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under projects FIRECAST (PCIF/GRF/0204/2017) and IMPECAF (PTDC/CTA-CLI/28902/2017).

How to cite: Alonso, C. and Gouveia, C.: Performance Evaluation of Fire Risk Map from LSA-SAF over Mediterranean region in 2020, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12863, https://doi.org/10.5194/egusphere-egu21-12863, 2021.

Fires negatively affect the composition and structure of fauna and flora, as well as the quality of air, soils and water. They cause economic losses and pose a risk to human life. Poland is at the forefront of European countries in terms of forest fires. Therefore, Institute of Meteorology and Water Management - National Research Institute (IMWM-NIR) implemented fire danger forecast system based on high-resolution (2.5 km) Weather Research and Forecast (WRF) model. Forecasted meteorological data are used to calculate parameters of Canadian Forest Fire Weather Index (FWI) System: Fire Weather Index (FWI), Initial Spread Index (ISI), Buildup Index (BUI), Fine Fuel Moisture Code (FFMC), Duff Moisture Code (DMC), and Drought Code (DC). Each parameter is presented in one of the classes corresponding to the fire danger – from low to extreme. In this way, a daily 24- and 48-hour fire danger forecasts are generated for the whole area of Poland and presented on IMWM-NIR meteorological website (meteo.imgw.pl).

In this presentation we show analyses of reliability of implemented FWI system. For this purpose, data reprocessing from March to September 2019 were made. Also data on fires occurrence on forest lands: time of occurrence, characteristics and location, from the resources of the State Fire Service were collected. Finally, for the selected period, we obtained a dataset of about 8 thousand events for which we assigned values of FWI parameters. Generally, based on our analysis, correlation between number of fires and averaged value of FWI amounted over 0.8. We found out, the correlation coefficient calculated for regions differ. The correlation is higher in central and northern Poland compared to the eastern part of the country, which also correspond to the number of fires. This may be related to the different forest structure - there is a higher proportion of broadleaf forests in the east. The comparison of 24- and 48-hour forecasts showed that they have similar reliability.

How to cite: Gruszczynska, M., Mandal, A., Nykiel, G., Strzyzewski, T., Wronska, W., Jaczewski, A., and Figurski, M.: Evaluation of the reliability of the high-resolution WRF fire danger forecasts in Poland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14602, https://doi.org/10.5194/egusphere-egu21-14602, 2021.

Fire is an important cause of disturbance in terrestrial ecosystems and can have a major impact on biodiversity. Long-term forest plot monitoring in Mato Grosso state (Brazil) indicates lowest species diversity in plots that have been burned multiple times and increasing species richness with time since the last fire. Furthermore, there is a strong positive relationship between species richness and basal area in unburnt and once-burnt plots, especially in the large tree stratum. We used high-resolution Landsat and PALSAR data at varying spatio-temporal (single and bi-temporal) scales to (a) assess Vegetation Indices sensitive to varying fire severity for different tropical forest species; (b) quantify fire severity and basal area/ biomass changes (1999, 2006, 2010, 2013); and (c) quantify the sensitivity of L-band backscatter to fuel load, moisture content and basal area/ biomass dynamics.

How to cite: Ningthoujam, R., Prestes, N. C. C. D. S., Feldpausch, T. R., Wooster, M., Harrison, S. P., and Prentice, I. C.: Fire-related forest properties observed using Landsat and radar data, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9834, https://doi.org/10.5194/egusphere-egu21-9834, 2021.

Deforestation in Indonesia in recent decades has made increasingly large parts of the region vulnerable to fires. Burning is particularly widespread in deforested peatlands, and it leads to globally significant carbon emissions. Here we use satellite-based observations to assess loss and fragmentation of primary forests and associated changes in fire regimes in Sumatra and Kalimantan between 2001 and 2019. We find that fires did not penetrate undisturbed primary forest areas deeper than two kilometres from the forest edge irrespective of drought conditions. However, fire-resistant forest now covers only 3% of peatlands and 4.5% of non-peatlands; the majority of the remaining primary forests are severely fragmented or degraded due to proximity to the forest edge. We conclude that protection and regeneration of the remaining blocks of contiguous primary forest, as well as peatland restoration, are urgently needed to mitigate the impacts of potentially more frequent fire events under future global warming.

How to cite: Nikonovas, T., Spessa, A., Doerr, S., Clay, G., and Mezbuhaddin, S.: Near-complete loss of fire-resistant primary tropical forest cover in Sumatra and Kalimantan, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16431, https://doi.org/10.5194/egusphere-egu21-16431, 2021.

Wildfires have posed increasing risks to human health and loss of life and property. Observations of wildfire remain limited, particularly the plume variables such as injection height and wind velocity critical to assessing wildfire impacts. Lack of adequate spatiotemporal coverage and measurement accuracy hinder predictability and initialization needed by weather and chemical transport models. The new observations from the emerging stereo wind and aerosol imaging techniques with LEO-GEO and GEO-GEO satellites offer an unprecedented opportunity to study wildfire dynamics and evolution processes in great detail. The diurnal coverage of the GEO-GEO winds stereo products (Carr et al., 2020, 2019, 2018) and the daytime coverage (and detail) of GEO multi-angle aerosol products (Limbacher et al., 2021; In Prep) can capture and further our understanding of intense wildfire dynamics (e.g., pyroCb), planetary boundary layer (PBL) variations, and direction of aerosol loadings. Using two new satellite-based stereoscopic tracking algorithms, we compare stereo observations directly with the Coupled WRF-CMAQ simulations (Zou et al., 2019) to diagnose the modeled plume injection height and wind velocity, and aerosol properties (Friberg et al., 2021; In Prep). The validated LEO-GEO winds and height algorithm provides plume dynamics data with an accuracy of 200 m vertical resolution for plume height and 0.5 m/s for plume speed. Using these stereo algorithms, we can determine if fire plumes stay within or shoot above PBL, which plays a critical role in plume transport and air quality. From the GEO-based observations of dynamic wildfire aerosol loading dispersion, height, and winds, we can track wildfire development at a sub-hourly frequency and capture extreme and/or rare events such as pyroCb that often occur in a short period of time and are largely missed by LEO satellites.

References:

Carr, J.L., Wu, D.L., Daniels, J., Friberg, M.D., Bresky, W., Madani, H. “GEO-GEO Stereo-Tracking of Atmospheric Motion Vectors (AMVs) from the Geostationary Ring,” Remote Sensing, 2020 https://doi.org/10.3390/rs12223779

Carr, J.L., D.L. Wu, R.E. Wolfe, H. Madani, G. Lin, B. Tan, “Joint 3D-Wind Retrievals with Stereoscopic Views from MODIS and GOES,” Remote Sensing, 2019, Satellite Winds Special Issue https://doi.org/10.3390/rs11182100

Carr, J.L., D.L. Wu, M.A. Kelly, and J. Gong, “MISR-GOES 3D Winds: Implications for Future LEO-GEO and LEO-LEO Winds,” Remote Sensing, 2018, MISR Special Issue. https://www.mdpi.com/2072-4292/10/12/1885

Limbacher, J. A., R. A. Kahn, and M. D. Friberg “A Multi-Angle Geostationary Aerosol Retrieval Algorithm,” 2021 [In Prep].

Zou, Y., O’Neill, S.M., Larkin, N.K., Alvarado, E.C., Solomon, R., Mass, C., Liu, Y., Odman, M.T., Shen, H. “Machine learning based integration of high-resolution wildfire smoke simulations and observations for regional health impact assessment. International Journal of Environmental Research and Public Health, 2019. https://doi.org/10.3390/ijerph16122137

Friberg, M.D., Wu, D.L., Carr, J.L., Limbacher, J. A., Zou^, Y., O’Neill, S. “Diurnal Observations of Wildfires Boundary Layer Dynamics and Aerosol Plume Convection using Stereo-Imaging Techniques,” 2021 [In Prep].

How to cite: Friberg, M., Wu, D., Carr, J., Limbacher, J., Zou, Y., and O'Neill, S.: Diurnal Observations of Wildfires Boundary Layer Dynamics and Aerosol Plume Convection using Stereo-Imaging Techniques, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16351, https://doi.org/10.5194/egusphere-egu21-16351, 2021.

MODIS has provided an 18-year continuous record of global fire activity. Here we present a geospatial analysis of MODIS hotspots in the high latitudes of the northern hemisphere from 2003 through to 2020. By combining the hotspot data with multiple land-cover datasets relating to vegetation cover, permafrost, and peat, we investigate boreal and tundra wildfire regimes, including an assessment of a significant northwards shift and increase in fire activity in 2019 and 2020. We focus on the distribution of hotspots on high latitude peatlands and permafrost and the associated difficulties in confirming residual smouldering compustion of peat soils using current remote sensing technology.

How to cite: Smith, T., McCarty, J., Turetsky, M., and Parrington, M.: Geospatial analysis of Arctic fires in the MODIS era: 2003–2020, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16198, https://doi.org/10.5194/egusphere-egu21-16198, 2021.

The boreal summers of 2019 and 2020 were witness to extensive high northern latitude wildfire activity, most notably within the Arctic Circle across eastern Russia. Near-real-time monitoring of the wildfire activity, based on satellite observations of active fires, showed widespread and persistent fires at a scale that had not been observed in the previous years that satellite observations are available. The European Centre for Medium-Range Weather Forecasts (ECMWF) through its operation of, and contribution to, different Copernicus Services is in a unique position to provide detailed information to monitor high-latitude wildfire activity, including their evolution and potential impacts, when they occur. Fire weather forecasts from the Copernicus Emergency Management Service (CEMS), and surface climate anomalies from the Copernicus Climate Change Service (C3S) both provide context to the environmental conditions required for wildfires to persist. Analyses based on observations of fire radiative power, along with analyses and forecasts of associated atmospheric pollutants, from the Copernicus Atmosphere Monitoring Service (CAMS) aid in quantifying the scale and intensity in near-real-time and the subsequent atmospheric impacts. We present an analysis of Arctic and high northern latitude wildfires during the summers of 2019 and 2020, reviewing the underlying meteorological/climatological conditions, the estimated emissions and transport of smoke constituents over the Arctic Ocean. We will show that the different datasets, while being relatively independent, show a strong correspondence and provide a wealth of information required to monitor and provide context for wildfire activity.

How to cite: Parrington, M., McCarty, J., Smith, T., Turetsky, M., Di Giuseppe, F., Vitolo, C., Garrigues, S., Ades, M., Agusti-Panareda, A., Barre, J., Engelen, R., Flemming, J., Inness, A., Kipling, Z., Peuch, V.-H., Wooster, M., Zhang, T., De Jong, M., and Vamborg, F.: Monitoring Arctic and high-latitude wildfires in 2019 and 2020, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13273, https://doi.org/10.5194/egusphere-egu21-13273, 2021.

Across much of the high latitudes, wildfires have been increasing in frequency, area burned, and severity in response to longer fire seasons, more severe fire weather, and increased ignitions. These fires not only affect the tundra and boreal forests they burn, but also global climate due to the high levels of carbon emitted during combustion that take decades to re-aggrade. Carbon emissions from high latitude fires are generally not included in global models that inform policy nor emissions reductions commitments from relevant countries. In this presentation we describe recent progress and critical unknowns related to intensifying fire regimes in high latitude ecosystems, with a particular focus on (i) trends in burned area and large fire years; (ii) changing ignitions sources including lightning, human, and overwintering fires; (iii) patterns and drivers of carbon emissions, including interactions with permafrost; (iv) implications for global carbon budgets; and (v) potential climate mitigation through increased resources for carbon-focused fire management.

How to cite: Rogers, B., Elder, M., Frumhoff, P., Gasser, T., Kukavskaya, E., MacDonald, E., Mack, M., Natali, S., Phillips, C., Scholten, R., Treharne, R., Veraverbeke, S., and Walker, X.: Intensifying fire regimes in the arctic-boreal zone: recent changes, global implications, and possible solutions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6404, https://doi.org/10.5194/egusphere-egu21-6404, 2021.

The circumpolar boreal biome is affected by increases in fire frequency and severity associated with climate warming. About 30% of the world’s terrestrial carbon (C) is stored in the boreal region. Fires can produce large C emissions when substantial amounts of aboveground and belowground biomass and soil organic matter are combusted. Quantification and understanding of the drivers of C combustion is crucial to better assess the role of boreal fires in the global carbon cycle.

Despite the fact that the majority of boreal burned area occurs on the Eurasian continent, relatively few measurements of C combustion have been made in Eurasian boreal ecosystems. Here we synthetized data from 41 field sites collected during the summer of 2019 in Eastern Siberian larch forests. C combustion from surface and stand-replacing fires varied between 1.54 and 5.38 kg C/m². Belowground pools contributed in average to 73.9% of total C combustion. C combustion was higher in open larch-dominated forests (Larix cajanderi) and open forests with a mixture of larch and pine (Pinus sylvestris). High severity crown fires were observed in dense larch-dominated forests, yet C combustion was in average 23% lower than in the open stands. To our knowledge, this study is the first to quantify C combustion from wildfires in a continuous permafrost terrain in Northeast Siberia. We also investigated the effects of fire weather and pre-fire stand characteristics (e.g., stand age, drainage conditions, overstory tree species composition) on C combustion.

Because fires can also have a longer-term impact on permafrost environments through changes in surface energy balance and ground thermal regime, we also quantified active layer deepening in our study area. We measured thaw depth in 13 burned and 6 unburned sites one year after the fire. We explored the interactions between fire, vegetation, drainage conditions, and thaw depth. Our study shows that fire deepens the active layer, yet the magnitude of the effect is controlled by vegetation characteristics and topo-edaphic factors. Our findings provide insight to feedbacks between climate warming and boreal fires in permafrost-underlain larch forests in Siberia.

How to cite: Delcourt, C. J. F., Akhmetzyanov, L., Izbicki, B., Kukavskaya, E. A., Mack, M. C., Maximov, T. C., Petrov, R. E., Rogers, B. M., Sass-Klaassen, U., Scholten, R. C., Shestakova, T. A., van Wees, D., and Veraverbeke, S.: Drivers of carbon emissions and active layer thickening from boreal wildfires in a continuous permafrost region of Northeast Siberia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1355, https://doi.org/10.5194/egusphere-egu21-1355, 2021.

Fire severity is a key fire regime characteristic with high ecological and carbon cycle relevance. Broadly defined, fire severity is a measure of the immediate impacts of a fire on the landscape, including the destruction and combustion of live vegetation and dead organic matter. Prior studies on boreal forest fires have mainly focused on mapping severity in North America’s boreal forests. However, the dominant tree species and their impacts on fire regimes are strikingly different between boreal North America and Siberia. Here we used Sentinel-2 satellite imagery to test the potential for using the most common spectral index for assessing fire severity, the differenced Normalized Burn Ratio (dNBR), over two fire scars and 41 field plots in Northeast Siberia. These field plots, sampled in the summer of 2019, corresponded to three different forest types: dense larch-dominated (Larix cajanderii) forest, open larch-dominated forest and open forest with a mixture of larch and pine (Pinus sylvestris). For this evaluation, the dNBR was compared to field measurements of the Geo Composite Burn Index (GeoCBI) and burn depth. The dNBR performed better when the field data were grouped by forest type (e.g. GeoCBI- dNBR R² = 0.38 (p < 0.01) for all plots and 0.49 (p < 0.001) for open larch forest). The GeoCBI provides a holistic field assessment of fire severity, yet it is dominated by the effect of fire on vegetation. Nevertheless, the GeoCBI correlated reasonably well with the depth of burning in the organic soil (R² = 0.11, p < 0.05 for all plots). This relationship also varied among forest types, and was the highest for the dense larch forests (burn depth- GeoCBI R² = 0.27, p < 0.05). The dNBR showed some potential as a predictor for burn depth, especially in the dense larch forests (burn depth- dNBR R² = 0.31, p < 0.05). This is line with previous studies in boreal North America. More research is needed to refine spaceborne fire severity assessments in the larch forests of Northeast Siberia, including assessments of additional fire scars and integration of dNBR with other geospatial proxies of fire severity.

How to cite: Combee, A., Delcourt, C. J. F., Izbicki, B., Mack, M. C., Maximov, T. C., Petrov, R. E., Rogers, B. M., Scholten, R. C., Shestakova, T. A., van Wees, D., and Veraverbeke, S.: Evaluating the differenced Normalized Burn Ratio for assessing fire severity using Sentinel-2 imagery in Northeast Siberian larch forests, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2518, https://doi.org/10.5194/egusphere-egu21-2518, 2021.

Increases in arctic and boreal fires can switch these biomes from a long-term carbon (C) sink to a source through direct fire emissions and longer-term emissions from soil respiration. Landscapes of intermediate drainage tend to experience the highest C combustion, dominated by soil C emissions, because of relatively thick and periodically dry organic soils. These landscapes may also induce a climate warming feedback through combustion and post-fire respiration of legacy C – soil C that had escaped burning in the previous fire – including from permafrost thaw and degradation. Data shortages from fires in tundra ecosystems and Eurasian boreal forests limit our understanding of C emissions from arctic-boreal fires. Interactions between fire, topography, vegetation, soil and permafrost need to be considered when estimating climate feedbacks of arctic-boreal fires.

How to cite: Veraverbeke, S., Delcourt, C., Granath, G., Kukavskaya, E., Mack, M., Strengbom, J., Walker, X., Hessilt, T., Rogers, B., and Scholten, R.: Carbon emissions from fires in permafrost peatlands, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2355, https://doi.org/10.5194/egusphere-egu21-2355, 2021.

Fire is the most important landscape disturbance in the boreal forest of North America. The boreal region is the largest terrestrial biome and stores approximately 35 % of the global soil carbon (C). Burned area has increased over the last decades and is projected to increase further in the future, potentially altering boreal forest ecosystems from a net sink of C to a source of C. Approximately 90 % of the burned area in the region originates from wildfires ignited by lightning strikes. It is therefore important to understand the drivers of lightning-induced wildfires to evaluate the consequences of possible future changes in lightning activity and ignition efficiency. Here, we evaluated lightning ignition efficiency, i.e. the probability that a lightning strike starts a fire, for Alaska and Northwest Territories between 2001 and 2018 in function of three sets of drivers: lightning characteristics, topography, and fire weather. Further, we projected the lightning ignition efficiency under the RCP8.5 scenario and combined it with predictions of future lightning activity to assess future lightning ignition.
            The logistic model demonstrated an overwhelming influence of fire weather on lightning ignition efficiency (area under the curve > 0.83), whereas lightning characteristics and topography contributed relatively little to the model performance. We found that short-term drying of the organic soils is the most important requirement for a lightning strike to start a fire. The average lightning ignition efficiency for Alaska and Northwest Territories increased with 54 ± 32 % and 44 ± 44 by 2100. Combined with future projections of lightning activity, we predicted a total increase in lightning ignition of up to 230 ± 20 % and 92 ± 56 % for Alaska and Northwest Territories by 2100. Future increases in lightning ignitions in the boreal forest will likely induce additional burned areas in regions with C-rich peatland and permafrost soils. Our research showed that the increased availability of dry fuels and increases in lightning will reinforce each other leading to more boreal fires and consequent C emissions.

How to cite: Hessilt, T. D., van der Werf, G., Abatzoglou, J. T., Scholten, R. C., and Veraverbeke, S.: Future increases in lightning-ignited boreal fires from conjunct increases in dry fuels and lightning, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2218, https://doi.org/10.5194/egusphere-egu21-2218, 2021.

Tundra fires are common across the pan-Arctic region, particularly in Alaska. Fires lead to significant impacts on terrestrial carbon balance and ecosystem functioning in the tundra. They can even affect the forage availability of herbivorous wildlife and living resources of local human communities. Also, interactions between fire and climate change can enhance the fire impacts on the Arctic ecosystems. However, the drivers and mechanisms of wildland fire occurrences in Alaskan tundra are still poorly understood. Research on modeling contemporary fire probability in the tundra is also lacking. This study focuses on exploring the critical environmental factors controlling wildfire occurrences in Alaskan tundra and modeled the fire ignition probability, accounting for ignition source, fuel types, fire weather conditions, and topography. The fractional cover maps of fuel type components developed Chapter 2 serve as input data for fuel type distribution. The probability of cloud-to-ground (CG) lightning and fire weather conditions are simulated using WRF. Topographic features are also calculated from the Digital Elevation Model (DEM) data. Additionally, fire ignition locations are extracted from Moderate Resolution Imaging Spectroradiometer (MODIS) active fire product for Alaskan tundra from 2001 to 2019. Empirical modeling methods, including RF and logistic regression, are then utilized to model the relationships between environmental factors and wildfire occurrences in the tundra and to evaluate the roles of these factors. Our results suggested that CG lightning is the primary driver controlling fire ignitions in the tundra, while warmer and drier weather conditions also support fires. We also projected future potential of wildland fires in this tundra region with Coupled Model Intercomparison Projects Phase 6 (CMIP6) data. The results of this study highlight the important role of CG lightning in driving tundra fires and that incorporating CG lightning modeling is necessary and essential for fire monitoring and management efforts in the High Northern Latitudes (HNL).

How to cite: He, J., Loboda, T., French, N., and Chen, D.: Exploring environmental factors driving wildfire occurrences in Alaskan tundra, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3735, https://doi.org/10.5194/egusphere-egu21-3735, 2021.

Understanding the long-term fire history of larch forests in the permafrost zone of Central Siberia is essential for an assessment of the possible responses and feedbacks of forest ecosystems to climate change. The multi-proxy record from the area of the Evenkian field station of the Sukachev Institute of Forest SB RAS, located in the middle part of the Lower Tunguska river basin provides important new data on the fire frequency, vegetation changes and paludification dynamics in the Central Evenkia over the last 3.5 ka BP. The new results of radiocarbon dating, loss on ignition, plant macrofossil and macro charcoal analyses from a sediment core taken in the waterlogged larch forest (N 64°09'56.1" E 100°31'43.9") are presented.

The obtained data have shown that fires were an important factor in the evolution of forest ecosystems in this continuous permafrost regions and acted as a trigger for the paludification process in the study area. The reconstruction of fire frequency demonstrated that the fire return period in the warm epochs of the late Holocene (3.6-2.7 ka BP, 1.5-0.7 ka BP, including the Medieval Climate Anomaly) varied from 115 to 150 years, and increased to 275-300 years during the periods of cooling (2.7-1.5 ka BP; the Little Ice Age, 0.7-0.15 ka BP). We suggested that the shorter and possibly colder summers during the cold epochs led to a decreased evaporation and a rise of ground moisture in many habitats, which was unfavorable for the occurrence and extension of forest fires. During the last 200 years the frequency of forest fires in the study area increased significantly, the fire return period reduced to a minimum value for the entire period under consideration (i.e. the last 3.5 ka BP) and reached 80 years. The fire free interval revealed from the macro charcoal analyses for the last 200 years is close to the average fire free interval reconstructed by dendrochronological data from the study area for the same period. The low human impact on forest ecosystems due to remote location of study area from settlements and mining regions suggests the natural causes of these fires.

This work was supported by the Russian Science Foundation, project № 20-17-00043.

How to cite: Novenko, E., Mazei, N., Kupryanov, D., and Prokushkin, A.: The Late Holocene forest fire history in continuous permafrost zone of Central Siberia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5509, https://doi.org/10.5194/egusphere-egu21-5509, 2021.

Holocene fire history of the southern Lake Baikal region

The catastrophic fire years that have taken place during the last decade in Siberia and in the boreal forests in general, directly linked to global warming, have had dramatic repercussions on the human populations of these regions. Past fire reconstruction studies are currently the only way to study the past dynamics of these fires and to understand their link with climate, vegetation and human activities. However, few studies of the dynamics of these fires are available in Siberia, and none have been carried out on the scale of the Holocene. This study aims to present the first reconstruction of the fire history during the Holocene based on sedimentary charcoals from two lakes localised on the southern shore of Lake Baikal, in Siberia. Two lakes have been sampled, Lake Ébène and Lake Jarod. The results showed a similar trend between the two lakes,with severe and intense crown fires during the early Holocene and less severe surface fires after 6 500 cal. yr BP. According to pollen reconstructions carried out near the studied lakes, a vegetation transition occurred at the same time. Picea obovata was dominant during the early humid Holocene. After 6 500 cal. yr BP, conditions were drier and Pinus sylvestris and Pinus sibirica became the dominant species. Over the past 1 500 years, the greater presence of human populations has firstly resulted in an increase of the fire frequency, then probably in its maintenance after 600 cal. yr BP in lake Ébène and to finish, in its suppression after 900 cal. yr BP in Lake Jarod. The decrease of fire frequency at the end of the 20th century could be explained by new fire management policies.

How to cite: Vogel, M., Barhoumi, C., Limani, H., Joannin, S., Peyron, O., and Ali, A. A.: Holocene fire history of the southern Lake Baikal region, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9967, https://doi.org/10.5194/egusphere-egu21-9967, 2021.

Wildfires are an essential ecological process, located at the interface between atmosphere, biosphere, and geosphere. Climate-related changes in their appearance and frequency will shape the boreal forest of tomorrow, the largest terrestrial biome responsible for numerous important ecosystem functions. Changing fire regimes could also increase pressure on fire management and become a threat for humans living in Siberia. However, a lack of long-term fire reconstructions complicates the understanding of the main drivers in the larch-dominated forests of eastern Siberia. At the same time, this lack of long-term understanding also aggravates the validation of fire-vegetation models, and thus predictions of future changes of fire regimes in this vital region.

Here, we present a new fire module being built for the individual-based, spatially explicit vegetation model LAVESI (Larix Vegetation Simulator). LAVESI is able to simulate fine-scale interactions in individual tree’s life stages and detailed population dynamics, now expanded by the ability of wildfires igniting and damaging biomass. Fire-vegetation simulations were computed around the catchment of Lake Khamra (SW Yakutia), which experienced forest fires in the years 2007 and 2014 according to remote sensing imagery. From the lake, we previously contributed a new, sedimentary charcoal-based fire reconstruction of the late Holocene. Testing the fire module at a current study site, where modern and historic data has already been collected, allows us to improve it, and look into ways in which the fire reconstruction might help inform the model, before eventually scaling it up to cover larger regions. This represents a first step towards a reliable fire-vegetation model, able to predict future impacts of fires on both the forests of eastern Siberia, as well as the humans living there.

How to cite: Glückler, R., Dietze, E., Gloy, J., Herzschuh, U., and Kruse, S.: Towards a better understanding of Siberian wildfires: linking paleoenvironmental fire reconstructions with an individual-based spatially explicit fire-vegetation model, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10840, https://doi.org/10.5194/egusphere-egu21-10840, 2021.

Fire is an important environmental and ecological process in northern high latitude environments. It is unclear how fire will respond to modern environmental change in this region and its implications for ecosystem processes and human societies. For insight into the long-term evolution of fire regimes, we reconstruct changes in biomass burning in the northern extratropics (>45°N) from the early Holocene (9000 years ago) to the present using the Reading Palaeofire Database, currently the most comprehensive repository of northern extratropical palaeo charcoal records. We examine the different geographic patterns in fire regimes across the northern extratropics from the sub-continental to circum-northern extratropical scale, by quantitatively comparing biomass burning with insolation, CO₂,human population records land cover changes. This study provides novel insight into the fire regimes that have characterized the northern extratropics over the Holocene and the differential importance of environmental controls in shaping these burning histories.

How to cite: Kesner, D., Harrison, S., Blyakharchuk, T., Edwards, M., Garneau, M., Magnan, G., and Prentice, C.: Spatial variability in Holocene wildfire responses to environmental change in the northern extratropics , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4846, https://doi.org/10.5194/egusphere-egu21-4846, 2021.

Throughout the Mediterranean biome, fire has been a dominant natural agent of change and a primary tool for anthropogenic landscape modifications. This research explores linkages among fire, vegetation, and human agricultural practices in the Eastern Mediterranean region, a region with limited evidence of the role these processes have in shaping the landscape.

Olive horticulture is among the oldest and most widespread agricultural forms in the Mediterranean Basin. The first major olive cultivation can be traced back in time with pollen evidence. In the Sea of Galilee, the earliest palynological evidence for olive horticulture suggest cultivation began approximately 7000 cal yr BP.

Here, we present a new high-resolution macro-charcoal dataset from the Sea of Galilee prior and during the first olive cultivation. Charcoal morphotypes were identified and are used to characterize fuel types. We also compare our data with a new multi-proxy dataset from the same record indicating the timing and impact of olive cultivation and related vegetation and climate changes.

The following questions are discussed: What was the natural fire regime (pre-large scale agriculture) around the Sea of Galilee basin? What role did fire play as a potential tool for clearing and fertilizing landscapes as the first olive orchards developed? How did fire regimes change once olive orchards were planted? Finally, can charcoal morphotypes provide novel insights into understanding paleofire regimes?

This study allows a new perspective into natural fire regimes in the Levant and an increased understanding of the role of fire during early horticulture practice. Moreover, it can serve as a basis for future fire management plans.

How to cite: Miebach, A., Resag, T. R., Netzel, T., and Power, M. J.: Fire and first olive cultivation: a new high-resolution macro-charcoal record from the Sea of Galilee, Israel, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2475, https://doi.org/10.5194/egusphere-egu21-2475, 2021.

Nowadays, the Mediterranean region is strongly impacted by fires. Projected warming scenarios suggest increasing fire risk in this region considered as hot-spot of the climate change (Liu et al., 2010; Pechony and Shindell, 2010). However, models based on modern-day statistical relationships do not properly account for interactions between climate, vegetation, and fire. In addition, process-based models must be tested not only against modern observations but also under different past climate conditions reflecting the range of climate variability projected for the next centuries (Hantson et al. 2016). Marine sediments are a major source of fire history of nearby land masses. Here, we present a unique 8,500 yr long record of biomass burning changes from southeastern France based on a marine microcharcoal sedimentary record from the Gulf of Lion, located in the subaqueous Rhone river delta. Sediment delivery to the Gulf of Lion comes mainly from the Rhône River draining a large watershed in southeast France (ca.100,000 km2). Due to the direction of dominant winds blowing from the North-North-West (Mistral and Tramontane) and carrying fine particles from the land to the sea, the microcharcoal record likely reflects the biomass burning in the Rhone watershed and South-East of France. Our results show multi-centennial to millennial changes in biomass burning with a periodicity  of 1000 years for the full record and between 500 and 700 years before 5,000 cal BP and after 3,000 cal BP. Large peaks of biomass burning are associated with marked dry periods observed in the region. Burning of biomass is higher when the region is dominated by xerophytic vegetation than when mesophyte vegetation dominates. The trend and periodicity of the biomass burning record suggest a predominant climatic control of fire occurrences since 8,500 cal BP in this region.

How to cite: Genet, M., Daniau, A.-L., Bassetti, M.-A., Jallali, B., Sicre, M.-A., Azuara, J., Berné, S., and Georget, M.: Reconstruction of fire regime changes in the French Mediterranean region during the last 8,500 years using microcharcoal , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6008, https://doi.org/10.5194/egusphere-egu21-6008, 2021.

Anthropogenic land-use change and ecosystem management have a demonstrable impact on modern fire regimes. However, when in time this influence was first felt is still an open question. We investigate whether an anthropogenic signal can be identified in Holocene fire records from the Iberian Peninsula, a region with abundant palaeoenvironmental and archaeological data. We analyse sedimentary charcoal data from 49 sites across the Peninsula covering part or all of the past 12,000 years to construct the fire history for the region. We compare these records to the summed probabilities of radiocarbon-dated archaeological sites, which provides an index for changes in human impact on land use and land cover due to the growth or decrease in human population through time. This reconstruction is based on 8200 radiocarbon dates covering the timespan between12000 and 3500 uncal BP.  Our analyses confirm that the broad trends in fire history are well aligned with the likely impact of climate changes during the Holocene. The charcoal records indicate a rapid increase in fire at the end of the Younger Dryas, a reduction in fire during the middle Holocene as a result of wetter conditions across the Peninsula, and an increase in fire concordant with the increased aridity registered during the interval after 3000 yr BP. However, finer-scale temporal variations are superimposed upon these broadscale changes. Similarly, although the most pronounced change in population reflects population growth associated with the onset of agriculture in the mid-Holocene, the summed probability record of population shows considerable finer-scale temporal variation. In addition to analyses of the temporal correlations between the two data sets, we consider whether there are distinct geographic patterns that could provide additional insights into the relationship between human activities and fire across Iberia.

How to cite: Sweeney, L., Vander Linden, M., and Harrison, S.: Anthropogenic land use change and fire history during the Holocene in the Iberian Peninsula, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2933, https://doi.org/10.5194/egusphere-egu21-2933, 2021.

Long-term perspectives on disturbance dynamics are important for the conservation of protected areas, yet restoration and conservation strategies in the Bohemian-Bavarian Forest Mountains do not consider the long-term role and patterns of forest fire, which is still deemed a negligible ecosystem disturbance in Central Europe. The scarcity of macroscopic charcoal studies in this area has likely hampered a complete understanding of local fire regime dynamics and its legacies in the present forest structure and composition. Here we used macroscopic charcoal (number, area and morphology of charred particles) and pollen analysis to investigate high resolution spatial and temporal patterns in Holocene fire regimes in the Bavarian-Bohemian Forest. We explored the relationship between changing forest composition dynamics and the influence topography had on spatial patterns of biomass burning. For this, we selected three lacustrine sites (two new, one published), located along a 30 km longitudinal transect within the studied area, at similar elevations in the mixed forest belt, with opposite (north vs. south) aspects. Results showed similar changes in biomass burning, fire frequency and peak magnitude at all sites, with a maximum during the early Holocene when fire resistant taxa (Pinus and Betula) dominated. Fire frequency decreased by half with the expansion of more fire-sensitive taxa (e.g., Picea and Fagus) during the mid-Holocene and reached a second maximum in the late Holocene, parallel with sustained increases in anthropogenic pollen indicators. We found a close north-south correspondence in the succession of fire patterns, i.e., fine-scale changes in biomass burning in the Bavarian Forest site (south-facing catchment) occurred around the same time with those observed at the Bohemian Forest sites (predominantly north-facing catchments), and these changes mirrored the Holocene dynamics of the main forest taxa. For example, the lowest biomass burning and peak magnitude intervals marked the beginning of Picea abies expansion at ~ 9 ka BP, Fagus sylvatica expansion at ~6 ka and Abies alba expansion at ~5 ka BP. Furthermore, we found a direct relationship between the abundance of charred morphotypes of conifer needles and deciduous leaves and the dominance of pine and birch in our pollen records, and a close correspondence between the abundance of non-woody charcoal morphotypes and pollen-derived landscape openness. Non-woody charcoal morphotypes dominated the charcoal records in the Early Holocene at the peak of biomass burning, whereas the abundance of woody morphotypes peaked around 6-8 ka BP and over the last millennium and their proportion in total charcoal influx increased starting 4 ka BP. Our study enables a better understanding of past and present fire regimes in the Bavarian-Bohemian Forest Mountains and highlights the need to consider the effects of fire as part of climate-change forest conservation strategies.

How to cite: Florescu, G., Kuneš, P., Tinner, W., Heurich, M., Finsinger, W., Moravcová, A., Dreslerová, D., Kletetschka, G., Vondrak, D., and Carter, V.: Holocene spatio-temporal patterns of biomass burning in the Bohemian-Bavarian Forest Mountains (Central Europe), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13342, https://doi.org/10.5194/egusphere-egu21-13342, 2021.

To distinguish human-caused from naturally-caused fire regimes, palaeoecological records must demonstrate that observed changes in vegetation and fire are in response to changes in human activity rather than driven by natural climate-fire relationships. Here, we use a high-resolution multi-proxy approach (testate amoebae derived depth to water table (DWT), macro- and micro-charcoal, charcoal morphologies, pollen, non-pollen palynomorphs, plant macrofossils, and XRF) from Pékna, a mid-elevation peat bog situated near Lipno Reservoir - an area rich in human land use - to investigate human-driven vs. naturally-driven fire regimes in the Šumava Mountains. Our results span the entire Holocene and illustrate that humans have been consistently modifying the landscape since 5,500 cal yr BP. Specifically, during the mid-Holocene (7,000 – 4,000 cal yr BP) when water table was at its highest at Pékna, relatively frequent, low-severity fires occurred and was accompanied by the prolonged presence of coprophilous fungi, secondary human indicators and an opening of the forest, suggesting human activities. Human land use intensified ~1,500 cal yr BP as indicated by increases in primary human indicator species, an increase in early successional tree species (Pinus and Betula) indicating an opening of the forest canopy, and the development of regional mining is suggested by a marked increase in the concentration of lead (Pb). While water table depths decreased indicating drier conditions ~1,500 cal yr BP, local fires persisted, burning at low severities as indicated by the continued presence of charred herb macrofossils. The most intensive land use occurred in the last 500 years with the highest abundance of primary and secondary human indicator species, and coprophilious fungi. Locally, marked increases in the concentration of both redox-sensitive elements such as iron (Fe), calcium (Ca), sulphur (S), and chlorine (Cl), and detrital elements such as potassium (K), aluminum (Al) and Titanium (Ti) indicate major changes in the depositional environment over the last 500 years, possibly due to peat draining. However, this time period witnessed decreased biomass burning as a result of a more open landscape and less fuels to burn. These results contribute to a growing body of literature illustrating the importance of prehistoric impact in the mid-mountains of Central Europe.   

How to cite: Kraklow, V., Moravcová, A., Kuneš, P., Dreslerová, D., Finsinger, W., Diaconu, A.-C., Nývlt, D., Kadlec, M., Tinner, W., Heurich, M., and Florescu, G.: Disentangling human-fire-climate linkages at mid-elevations in the Šumava Mountains of central Europe, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12821, https://doi.org/10.5194/egusphere-egu21-12821, 2021.

The mountainous area of Armenia has been a steppe throughout the Holocene with a rich history of fire events throughout this period. Previous research has found that changes in fire are linked to shifts between Poaceae grasslands and semi-arid Chenopodiaceae steppes. However, the climate and human drivers of these fires has yet to be fully explored in an area where agriculture has been practiced for almost 8,000 years. To elucidate these changes, we performed and compiled macro-charcoal analysis on four wetland sediment cores from the Kasakh Valley, Armenia. We aimed to understand fire frequency, intensity, size, and drivers of these events. In addition, we utilize a paleotemperature molecular biomarker branched glycerol dialkyl glycerol tetraethers (brGDGTs), a pollen climate reconstruction for temperature and precipitation, and the vast amount of archaeological data to help us untangle these changes. Early results suggest fires increase as temperature rose during the early Holocene and continue to increase with temperature during the Mid-Holocene despite an increase in agriculture during the Early Bronze Age. Between 4000 - 2000 cal. BP fires are small and almost disappear from the record. During this period these declines appear to be driven both by temperature fluctuations and an increase in regional mobile pastoralism resulting in declining biomass. Over the last 2000 years, humans appear to be the primary driver of fires with an increase in large intense events that are local to the watershed.

How to cite: Cromartie, A., Barhoumi, C., Dugerdil, L., Ménot, G., Peyron, O., Messager, E., Etienne, D., Khatchadourian, L., Badalyan, R., Smith, A. T., Meliksetian, K., and Joannin, S.: The human and climate drivers of Holocene grassland fires in the South Caucasus: A macro-charcoal, brGDGTs, and pollen reconstruction, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10442, https://doi.org/10.5194/egusphere-egu21-10442, 2021.

Fire is a worldwide terrestrial process and has shaped the ecosystems and life on Earth over millions of years. Today, fire regime metrics such as burned area, intensity and frequency, depend on a set of climatic and environmental variables, but under anticipated climate warming scenarios, it is projected that fire characteristics will change, posing great threats to the environment and society. Large uncertainties remain in better understanding this complex process, integrating it in Earth system global models and better forecasting the response of fire to future climate changes.

Paleofire records from marine sediments capture information about regional-scale relative changes in biomass burning over long timescale and can help understanding the relationships between climate change and fire activity. We still lack, though, what a change in biomass burning in the paleorecord means in terms of fire regimes.

The present study aims at exploring the link between charcoal accumulation in marine surface sediment samples of modern ages from about 150 sites across the African coast and fire regimes on land. It is based on an integrated approach using fire proxy, climate, environmental and historical information, and satellite data. Exploratory in character, this study is designed to investigate this link among different biomes, describing latitudinal and longitudinal transects, and to test the influence of different physical site-specific variables (climate, vegetation, size of the source area etc.) on land and transport-deposition processes into the marine realm.

This study aims to provide a novel sediment-based proxy for a key physical parameter unlocking specific technical and theoretical problems related to fire research; it may also help to better understand local to regional processes controlling the fire signal and contextualize current and past environmental changes.

How to cite: Haliuc, A., Daniau, A.-L., and team members, B.: Calibrating microcharcoal in recent marine sediments: implications to reconstruct paleofire regimes on African continent, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2575, https://doi.org/10.5194/egusphere-egu21-2575, 2021.