Monitoring Wildfires in Thailand: A Case Study of the ECSTAR-TeroSpace’s Earth Observation Project

The primary objective of this paper is to present a comprehensive case study on monitoring wildfires in Nakhon Nayok, Thailand, utilizing Earth observation platforms. This initiative project has been undertaken by the Excellence Center of Space Technology and Research (ECSTAR), in partnership with its spin-off startup, TeroSpace. The study aims to provide an in-depth analysis of the wildfire incidents in the region, utilizing advanced technologies such as satellite imagery and data analytics, and to identify ways to improve future wildfire management. In particular, the paper focuses on the wildfires including thermal area comparison that ravaged the land in Nakhon Nayok Province in central Thailand from March to April 18th, 2023. To conduct this study, the ECSTAR-TeroSpace analytic team utilized satellite images from Earth observation platforms: MODIS and Sentinel-2A. By presenting this case study, this paper contributes to the broader understanding of how to monitor and manage wildfires in a changing climate. The findings of this study underscore the importance of proactive and collaborative efforts in mitigating the negative impacts of wildfires in Nakhon Nayok and other regions in Thailand.

Contribution of biophysical and climate variables to the spatial distribution of wildfires in Iran

This study investigated the relationship between climate and biophysical variables in burned areas in Iran.The fire burned area(FBA)product(Fire CCI 5.1.1),land surface temperature(MOD11C3C),vegetation index(MOD13A1),and climate variables such as temperature,wind speed,relative humidity,and volumetric soil moisture from the ERA5 reanalysis dataset were used.Pearson correlation coefficient was used to determine the relationship between biophysical and climate variables and fire occurrence.The results show that FBA increased by 1.7 hectares/decade from 2001 to 2020.The high FBA in 2010(the black summer of Iran)was due to high temperatures and significant heatwaves that led to extensive wildfires.Although anthropogenic activities are considered a significant cause of wildfires,several variables,including increased temperatures,less precipitation,relative humidity,and wind speed and direction,contribute to the extent and occurrence of wildfires.The country’s FBA hotspot is in the Arasbaran region during the summer season.Temperature and relative humidity are the most significant variables influencing the occurrence of wildfires.The results show the vulnerability of Iran s forests and their high potential for fires.Considering the frequency of fire occurrences in Iran and the limited equipment,fire prevention plans should be carried out by applying proper management in high-risk regions.

Wildfires in Botswana and Their Frequency of Occurrence

Fires play an essential part in the maintenance of the environment, but amplified fire activity often leads to adverse effects in the environment such as destruction of property and loss of life. Botswana has experienced wildfires that are caused by humans intentionally and unintentionally. Some of these wildfires grow into mega fires such as the 2008 wildfires. Data of wildfires reported in Botswana from the Department of Forestry and Range Resources and the frequency of occurrence was studied and analyzed. It shows the period of 2006-2017, Ghanzi and Ngamiland districts were mostly affected by wildfires. These districts have protected land such as the wildlife parks which may lead to the outbreak of natural wildfires that burns unnoticed due to minimal movements of people. The wildfires reported in each district show an increase over the years and this may affect the smooth running of operations.

Repeated Wildfires in the Middle Jurassic Xishanyao Formation(Aalenian and Bajocian Ages) in Northwestern China

The coal-bearing strata in the southern Junggar Basin in northwestern China have recently attracted the attention of coal geologists. Its abundance of coal resources is of great interest as there is a potential of unlocking details about the palaeoclimatic information. Coal deposits have the capacity to record wildfire events, even those with inefficient combustions. To characterize wildfire events and palaeoclimatic history of the Middle Jurassic Xishanyao Formation(Aalenian and Bajocian ages), 22 coal samples from borehole cores and coal mines in the southern Junggar Basin were collected and their macerals were analyzed. The results indicated that fusinite and semi-fusinite were the dominant components of inertinite with proportions of 35.27% and 54.67%, respectively. The presence of inertinite is an indicator that wildfires occurred at the time of peat land development, and the widespread occurrence suggests large scale wildfires during the Middle Jurassic. This study proposes a new parameter for the evaluation of wildfire features by combining burning frequency and burning temperature. The comprehensive evaluation index(CEI) was influenced by the lacustrine basin level and ancient plant types from a sequence framework. During the Middle Jurassic, most wildfires were surface fires with low level and ground fire with high level. High oxygen levels were estimated in the lower, middle, and upper members of the Xishanyao Formation with corresponding to 26.78%, 24.55%, and 23.55%, respectively. The high oxygen levels would be the primary cause of repeated wildfires in the Middle Jurassic. These results are helpful for understanding palaeoclimatic changes in the Middle Jurassic.

Vegetation Regrowth Following Wildfires in the Santa Cruz Mountains of Northern California Monitored Using Landsat Satellite Image Analysis

The Santa Cruz Mountain range in northern California is a coastal landscape with a history of extensive forest logging and frequent large wildfires that have recently destroyed numerous residential structures at the wildland interface. Results from Landsat satellite image time-series analysis since 1984 of the study area within the Los Gatos Creek and Corralitos Creek watersheds showed that none of the severe drought periods since the 1980s have notably inhibited rapid tree and shrub regrowth rates on steep hill slopes burned recently by the 1985 Lexington Fire and the 2008 Summit Fire. In high burn severity areas of both fires, post-fire vegetation types showed a marked increase in shrub cover, mainly at the expense of evergreen tree cover. Most of these low (<3 m), dense stands of evergreen woody species have regenerated in as little as five years from bare charred ground. A combination of Landsat and Laser Altimeter (GLAS) satellite sensor data revealed that exposed south-facing slopes are presently supporting 200 to 240 Mg·ha-1 of standing woody biomass on the burned areas. This study is the first of its kind to utilize a full 30-year record of Landsat vegetation index data to monitor tree and shrub regrowth after stand-replacing wildfires in California.

A Critical Examination of the Relationship between Wildfires and Climate Change with Consideration of the Human Impact

The relationship between climate change and wildfires was examined to summarize factors associated with vulnerability to wildfires. The complex and cyclic nature of interaction effects between the two was highlighted and the following conclusions were drawn. Climate change is leading to more frequent wildfires with higher intensity, resulting in release of more gasses and particulate matter that further exacerbates the progression of climate change. Direct and indirect impacts are detailed in the main body. A new fire management policy is deemed necessary, with a more local approach being recommended. Human impacts were found to further complicate the already complex relationship. It is recommended to treat accidental and incendiary fires separately for the purpose of evaluating fire management regimes. This requires successful advances in current fire investigation techniques.

Landscape Patterns of Vegetation Canopy Regrowth Following Wildfires in the Sierra Nevada Mountains of California

Rapid recovery of pioneer shrub and forest patch cover can reduce soil erosion, nutrient runoff and degradation of stream habitats, and promote small mammal and avian biodiversity following stand-replacing wildfires. Landsat imagery from the past 25+ years was analyzed to understand patterns and rates of vegetation recovery, focusing on high burn severity (HBS) patches, within wildfire areas dating from the late 1940s in the Sierra-Nevada region of California. Normalized difference vegetation index (NDVI) levels indicative of recovered woody cover within HBS areas were analyzed starting in 1985 to quantify regrowth of patch dynamics. Analysis of landscape metrics showed that the percentage of total HBS area comprised by the largest patch of recovered woody cover was relatively small in all fires that occurred since 1995, but increased rapidly with time since fire. Patch complexity of recovered woody cover decreased notably after more than 50 years of regrowth, but was not readily associated with time for fires that occurred since the mid 1990s. Patch complexity of dense woody cover was consistently high in fires after 1995 and increased with the elevation of HBS areas. The aggregation level of patches with recovery of woody cover increased steadily with time since fire. The study approach using satellite remote sensing can be expanded to assess the consequences of stand-replacing wildfires in all forests of the region.

The use of charcoal to interpret Cretaceous wildfires and volcanic activity

Charcoal is abundant in most post-Silurian sedimentary sequences and even in some volcanic rocks. The study of charcoal can provide important information on not only what plants were being burned but also on how the charcoal residue was formed. Most charcoal encountered in the sedimentary record is a result of lightning-ignited wildfires but volcanic activity may also act as an ignition source. Charcoal preserves exquisite anatomical data that can be studied by a range of microscopical techniques including scanning electron microscopy that allows the identity of the plants to be determined. Fires have a major impact on a range of environments and ecosystems. The elevated oxygen content of the atmosphere indicates that the Cretaceous can be considered a "high-fire" world. Fire activity should be taken into account in Cretaceous vegetation and climate models. The occurrence of charcoal at the Cretaceous-Tertiary Boundary has been highlighted as evidence for a global fire following an asteroid impact, but this interpretation is questionable.Charcoal may be found within volcanic rocks, especially from deposits of pyroclastic flows and from basaltic lavas. This may provide data on the entombed vegetation but reflectance data may be used to provide interpretations of deposit temperatures. Charcoal is information-rich but yet is an under-utilized resource. Fire is an expression of life on Earth and an index of life's history and is relevant for geology, biology, human history, physics and global chemistry.

Theoretical Investigations on Mapping Mean Distributions of Particulate Matter,Inert,Reactive,and Secondary Pollutants from Wildfires by Unmanned Air Vehicles(UAVs)

Evaluated Weather Research and Forecasting model inline with chemistry (WRF/Chem) simulations of the 2009 Crazy Mountain Complex wildfire in Interior Alaska served as a testbed for typical Alaska wildfire-smoke conditions. A virtual unmanned air vehicle (UAV) sampled temperatures, dewpoint temperatures, primary inert and reactive gases and particular matter of different sizes as well as secondary pollutants from the WRF/Chem results using different sampling patterns, altitudes and speeds to investigate the impact of the sampling design on obtained mean distributions. In this experimental design, the WRF/Chem data served as the “grand truth” to assess the mean distributions from sampling. During frontal passage, the obtained mean distributions were sensitive to the flight patterns, speeds and heights. For inert constituents mean distributions from sampling agreed with the “grand truth” within a factor of two at 1000 m. Mean distributions of gases involved in photochemistry differed among flight patterns except for ozone. The diurnal cycle of these gases’ concentrations led to overestimation (underestimation) of 20 h means in areas of high (low) concentrations as compared to the “grand truth.” The mean ozone distribution was sensitive to the speed of the virtual UAV. Particulate matter showed the strongest sensitivity to the flight patterns, especially during precipitation.

Spatial Resilience to Wildfires through the Optimal Deployment of Firefighting Resources:Impact of Topography on Initial Attack Effectiveness

Strongly affected by the escalating impacts of climate change,wildfires have been increasing in frequency and severity around the world.The primary aim of this study was the development of specific territorial measures—estimating the optimal locations of firefighting resources—to enhance the spatial resilience to wildfires in the fire-prone region of Chalkidiki Prefecture in northern Greece.These measures focus on the resistance to wildfires and the adaptation of strategies to wildfire management,based on the estimation of burn probability,including the effect of anthropogenic factors on fire ignition.The proposed location schemes of firefighting resources such as vehicles consider both the susceptibility to fire and the influence of the topography on travel simulation,highlighting the impact of road slope on the initial firefighting attack.The spatial scheme,as well as the number of required firefighting forces is totally differentiated due to slope impact.When we ignore the topography effect,a minimum number of fire vehicles is required to achieve the maximization of coverage(99.2%of the entire study area)giving priority to the most susceptible regions(that is,employing 18 of 24 available fire vehicles).But when we adopt more realistic conditions that integrate the slope effect with travel time,the model finds an optimal solution that requires more resources(that is,employing all 24 available fire vehicles)to maximize the coverage of the most vulnerable regions within 27 min.This process achieves 80%of total coverage.The proposed methodology is characterized by a high degree of flexibility,and provides optimized solutions to decision makers,while considering key factors that greatly affect the effectiveness of the initial firefighting attack.

Towards understanding the environmental and climatic changes and its contribution to the spread of wildfires in Ghana using remote sensing tools and machine learning (Google Earth Engine)

Data processing and climate characterisation to study its impact is becoming difficult due to insufficient and unavailable data,especially in developing countries.Understanding climate’s impact on burnt areas in Ghana(Guinea-savannah(GSZ)and Forest-savannah Mosaic zones(FSZ))leads us to opt for machine learning.Through Google Earth Engine(GEE),rainfall(PR),maximum temperature(Tmax),minimum temperature(Tmin),average temperature(Tmean),Palmer Drought Severity Index(PDSI),relative humidity(RH),wind speed(WS),soil moisture(SM),actual evapotranspiration(ETA)and reference evapotranspiration(ETR)have been acquired through CHIRPS(Climate Hazards group Infrared Precipitation with Stations),FLDAS dataset(Famine Early Warning Systems Network(FEWS NET)Land Data Assimilation System)and TerraClimate platform from 1991 to 2021.The objective is to analyse the link and the contribution of climatic and environmental parameters on wildfire spread in GSZ and FSZ in Ghana.Variables were analysed(area burnt and the number of activefires)through Spearman correlation and the cross-correlation function(CCF)(2001 to 2021).The tests(Mann-Kendall and Sens’s slope trend test,Pettitt test and the Lee and Heghinian test)showed the overall decrease in rainfall and increase in temperature respectively(-0.1 mm;+0.8℃)in GSZ and(-0.9 mm;+0.3℃)in FSZ.In terms of impact,PR,ETR,FDI,Tmean,Tmax,Tmin,RH,ETA and SM contribute tofire spread.Through the codes developed,researchers and decision-makers could update them at different times easily to monitor climate variability and its impact onfires.

Soil resilience assessment using soil profile descriptions and Analytic Hierarchy Process in Mediterranean mountains considering diverse fire occurrences

Wildfires are complex natural phenomena that exert significant impacts on landscapes,societies,and economies.Understanding the concept of resilience is crucial in mitigating its possible negative impacts,as it involves preparing for,responding to,and recovering from wildfires.This research aims to demonstrate the utility of in situ soil profile description in assessing land use resilience using an Analytic Hierarchy Process(AHP)through an expert panel survey.The study examines a catchment located in the Balearic Islands,considering two fire occurrences(once and twice),comparing abandoned agricultural terraces and natural hillslopes.The results demonstrated that the priority ranking of variables to assess soil profile resilience against wildfires,determined by a panel of 10 experts,identified horizon depth(25.1%),slope inclination(21.5%),and hydrological connectivity(16.6%)as the most crucial factors.Other variables,such as number and size of roots,structure of pedal soil material,size class structure,and rock fragments,also contributed to resilience but to a lesser extent,with scores ranging from 5.7%to 9.6%.Analyzing the priorities established by the experts using AHP,the results showed that the least resilient soil horizon was H1 of the control hillslope,especially under high and low connectivity processes,which aligned with the loss of superficial soil horizons after one and two wildfires.Hillslopes showed greater changes in resilience after occurring wildfires compared to terraces,with the most significant alterations occurring after the second wildfire event.This study addresses a significant knowledge gap in the field by highlighting the interconnectedness of wildfires,resilience,and land use,providing insights into land management strategies for wildfire-prone regions.

2023: Weather and Climate Extremes Hitting the Globe with Emerging Features

Globally,2023 was the warmest observed year on record since at least 1850 and,according to proxy evidence,possibly of the past 100000 years.As in recent years,the record warmth has again been accompanied with yet more extreme weather and climate events throughout the world.Here,we provide an overview of those of 2023,with details and key background causes to help build upon our understanding of the roles of internal climate variability and anthropogenic climate change.We also highlight emerging features associated with some of these extreme events.Hot extremes are occurring earlier in the year,and increasingly simultaneously in differing parts of the world(e.g.,the concurrent hot extremes in the Northern Hemisphere in July 2023).Intense cyclones are exacerbating precipitation extremes(e.g.,the North China flooding in July and the Libya flooding in September).Droughts in some regions(e.g.,California and the Horn of Africa)have transitioned into flood conditions.Climate extremes also show increasing interactions with ecosystems via wildfires(e.g.,those in Hawaii in August and in Canada from spring to autumn 2023)and sandstorms(e.g.,those in Mongolia in April 2023).Finally,we also consider the challenges to research that these emerging characteristics present for the strategy and practice of adaptation.

A new approach to pedestal differentiation for soil loss estimation-a case study from a burnt area in north-central Portugal

Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth century.In agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'erosion.Little work has been reported on using capstone pedestal data for quantifying soil loss.We postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their populations.This analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate results.The three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed pedestals.In the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin size.This concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt plantation.We measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available literature.Soil pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the method.It is postulated that phoenix-and endo-pedestals may be a driving factor behind the observed discrepancies.We discuss how future research may provide more insight into dominant processes,and how frequency distributions may be used to select the best methods for estimating soil loss from pedestals.

Machine Learning Analysis of Impact of Western US Fires on Central US Hailstorms

Fires,including wildfires,harm air quality and essential public services like transportation,communication,and utilities.These fires can also influence atmospheric conditions,including temperature and aerosols,potentially affecting severe convective storms.Here,we investigate the remote impacts of fires in the western United States(WUS)on the occurrence of large hail(size:≥2.54 cm)in the central US(CUS)over the 20-year period of 2001–20 using the machine learning(ML),Random Forest(RF),and Extreme Gradient Boosting(XGB)methods.The developed RF and XGB models demonstrate high accuracy(>90%)and F1 scores of up to 0.78 in predicting large hail occurrences when WUS fires and CUS hailstorms coincide,particularly in four states(Wyoming,South Dakota,Nebraska,and Kansas).The key contributing variables identified from both ML models include the meteorological variables in the fire region(temperature and moisture),the westerly wind over the plume transport path,and the fire features(i.e.,the maximum fire power and burned area).The results confirm a linkage between WUS fires and severe weather in the CUS,corroborating the findings of our previous modeling study conducted on case simulations with a detailed physics model.

Southern Hemisphere Volcanism Triggered Multi-year La Niñas during the Last Millennium

To explain the recent three-year La Niña event from 2020 to 2022,which has caused catastrophic weather events worldwide,Fasullo et al.(2023)demonstrated that the increase in biomass aerosol resulting from the 2019-20 Australian wildfire season could have triggered this multi-year La Niña.Here,we present compelling evidence from paleo-proxies,utilizing a substantial sample size of 26 volcanic eruptions in the Southern Hemisphere(SH),to support the hypothesis that ocean cooling in the SH can lead to a multi-year La Niña event.This research highlights the importance of focusing on the Southern Ocean,as current climate models struggle to accurately simulate the Pacific response driven by the Southern Ocean.

Detection of Burned Areas through Spectral Indices Analysis of Sentinel-2A Satellite Images in the Abokouamékro Wildlife Reserve (Central, Côte D’Ivoire)

In Côte d’Ivoire, the recurring and unregulated use of bushfires, which cause ecological damage, presents a pressing concern for the custodians of protected areas. This study aims to enhance our comprehension of the dynamics of burnt areas within the Abokouamékro Wildlife Reserve (AWR) by employing the analysis of spectral indices derived from satellite imagery. The research methodology began with the calculation of mean indices and their corresponding spectral sub-indices, including NDVI, SAVI, NDWI, NDMI, BAI, NBR, TCW, TCG, and TCB, utilizing data from the Sentinel-2A satellite image dated January 17, 2022. Subsequently, a fuzzy classification model was applied to these various indices and sub-indices, guided by the degree of membership α, with the goal of effectively distinguishing between burned and unburned areas. Following the classification, the accuracies of the classified indices and sub-indices were validated using the coordinates of 100 data points collected within the AWR through GPS technology. The results revealed that the overall accuracy of all indices and sub-indices declines as the degree of membership α decreases from 1 to 0. Among the mean spectral indices, NDVI-mean, SAVI-mean, NDMI-mean exhibited the highest overall accuracies, achieving 97%, 95%, and 90%, respectively. These results closely mirrored those obtained by sub-indices using band 8 (NDVI-B8, SAVI-B8, and NDMI-B8), which yield respective overall accuracies of 93%, 92%, and 89%. At a degree of membership α = 1, the estimated burned areas for the most effective indices encompassed 2144.38 hectares for NDVI-mean, 1932.14 hectares for mean SAVI-mean, and 4947.13 hectares for mean NDMI-mean. A prospective approach involving the amalgamation of these three indices could have the potential to yield improved outcomes. This study could be a substantial contribution to the discrimination of bushfires in Côte d’Ivoire.

Characteristics of Early Cretaceous wildfires in peat-forming environment, NE China

Inertinite maceral compositions in coals from the Early Cretaceous Erlian, Hailar, and Sanjiang Basins in NE China are analyzed in order to reveal palaeowildfire events and palaeoclimate variations. Although huminite is the dominant maceral group in the studied basins, the inertinite group, as a byproduct of palaeowildfires, makes up a considerable proportion. Occurrence of inertinite macerals indicates that wildfires were widespread and frequent,and supports the opinion that the Early Cretaceous was a "high-fire" interval. Inertinite contents vary from 0.2% to 85.0%, mostly within the range of 10%–45%, and a model-based calculation suggests that the atmospheric oxygen levels during the Aptian and Albian(Early Cretaceous) were around 24.7% and 25.3% respectively. Frequent fire activity during Early Cretaceous has been previously related to higher atmospheric oxygen concentrations. The inertinite reflectance, ranging from 0.58%Ro to 2.00%Ro, indicates that the palaeowildfire in the Early Cretaceous was dominated by ground fires, partially reaching-surface fires. These results further support that the Cretaceous earliest angiosperms from NE China were growing in elevated O2 conditions compared to the present day.

Repeated occurrence of palaeo-wildfires during deposition of the Bahariya Formation(early Cenomanian) of Egypt

The Upper Cretaceous(early Cenomanian)Bahariya Formation of Egypt has an outstanding reputation for its wealth of vertebrate remains,including a variety of iconic dinosaurs,like the carnivorous Spinosaurus and Carcharodontosaurus,as well as the herbivorous Aegyptosaurus and Paralititan.Besides these dinosaur fossils,the Bahariya Formation yielded also a wealth of invertebrate and plant remains,but even today many aspects concerning the continental palaeoenvironments reflected in these deposits(including the occurrence of palaeo-wildfires)have not been studied in detail.So far six distinct macro-charcoal bearing levels could be identified within the type section of the Bahariya Formation at Gabal El Dist profile,one of the most prolific outcrops of this formation in terms of fossil occurrence located in the north of the Bahariya Oasis,Western Desert,Egypt.Most of the charcoal investigated by means of SEM originates from ferns,pointing to a considerable proportion of this plant group within the palaeo-ecosystems that experienced fires.Gymnosperms and(putative)angiosperms have less frequently been identified.The collected data present evidence that the landscapes at the northern shores of Gondwana repeatedly experienced palaeo-wildfires,adding extra proof to previous statements that the Late Cretaceous was a fiery world on a global scale.

Intensive peatland wildfires during the Aptian-Albian oceanic anoxic event 1b:Evidence from borehole SK-2 in the Songliao Basin,NE China

The Cretaceous has been considered a“high-fire”world accompanied by widespread by-products of combustion in the rock record.The mid-Cretaceous oceanic anoxic event 1b(OAE1b)is marked by one of the major perturbations in the global carbon cycle characterized by deposition of organic-rich sediments in both marine and terrestrial settings.However,our understanding is still limited on changes in wildfire activity during OAE1b period.Here,we carried out a comprehensive analysis,including organic carbon isotope(δ^(13)C_(org)),total organic carbon(TOC),coal petrology,trace elements,and pyrolytic polycyclic aromatic hydrocarbons(pyroPAHs),of coal seams of the middle Aptian to early Albian Shahezi Formation from borehole SK-2 in Songliao Basin,Northeast China.Two negativeδ^(13)C_(org) excursions in the Shahezi Formation can be corresponded with the 113/Jacob and Kilian sub-events of OAE1b.Moreover,the intensive peatland wildfires have been identified during the sub-event periods of OAE1b based on the co-occurrence of high abundance of charcoal and pyroPAHs at that time.In addition,Sr/Ba,Sr/Cu and Sr/Rb ratios demonstrate that enhanced peatland wildfires were controlled by dryer climate conditions owing to episodic northward migration of arid zones in East Asia related with rising global temperature during the sub-events of OAE1b.The climate-driven extensive wildfire activity in the mid-latitude terrestrial ecosystems can be a contributing factor for OAE1b through the increased flux of nutrients fuelling primary producers in the lake and marine environments and leading to more speculative anoxia to allow the deposition of organic-rich sediments.Our results provide essential understanding of the importance of wildfires in driving mechanism of oceanic anoxic events(OAEs)in Earth's history.