scholarly journals Self-Adjusting Thresholding for Burnt Area Detection Based on Optical Images

2019 ◽  
Vol 11 (22) ◽  
pp. 2669
Author(s):  
Edyta Woźniak ◽  
Sebastian Aleksandrowicz
Keyword(s):  
Automated Classification ◽  
Landsat Images ◽  
Burnt Area ◽  
Optical Images ◽  
Medium Resolution ◽  
Automatic Mapping ◽  
Neighbourhood Analysis ◽  
Object Oriented Approach ◽  
Multiresolution Segmentation ◽  
Burnt Areas

Mapping of regional fires would make it possible to analyse their environmental, social and economic impact, as well as to develop better fire management systems. However, automatic mapping of burnt areas has proved to be a challenging task, due to the wide diversity of vegetation cover worldwide and the heterogeneous nature of fires themselves. Here, we present an algorithm for the automatic mapping of burnt areas using medium-resolution optical images. Although developed for Landsat images, it can be also applied to Sentinel-2 images without modification. The algorithm draws upon the classical concept of differences in pre- and post-fire reflectance, but also takes advantage of the object-oriented approach and a new threshold calculation method. It consists of four steps. The first concerns the calculation of spectral indices and their differences, together with differences in spectral layers based on pre- and post-fire images. In the second step, multiresolution segmentation and masking are performed (clouds, water bodies and non-vegetated areas are removed from further analysis). Thirdly, ‘core’ burnt areas are detected using automatically-adjusted thresholds. Thresholds are calculated on the basis of specific functions established for difference layers. The last step combines neighbourhood analysis and patch growing to define the final shape of burnt areas. The algorithm was tested in 27 areas located worldwide, and covered by various types of vegetation. Comparisons with manual interpretation show that the fully-automated classification is accurate. Over 82% of classifications were considered satisfactory (overall accuracy > 90%; user and producer accuracy > 70%).

scholarly journals The history and characteristics of the 1980–2005 Portuguese rural fire database

2011 ◽  
Vol 11 (12) ◽  
pp. 3343-3358 ◽  
Author(s):  
M. G. Pereira ◽  
B. D. Malamud ◽  
R. M. Trigo ◽  
P. I. Alves
Keyword(s):  
Urban Areas ◽  
Unit Area ◽  
Fire Regime ◽  
Minimum Area ◽  
Burnt Area ◽  
Forested Areas ◽  
Large Fires ◽  
Burnt Areas

Abstract. We focus here on a mainland Continental Portuguese Rural Fire Database (PRFD) that includes 450 000 fires, the largest such database in Europe in terms of total number of recorded fires in the 1980–2005 period. In this work, we (a) list the most important factors for triggering and controlling the fire regime in mainland Continental Portugal, (b) describe the dataset's production, (c) discuss procedures adopted to identify and correct different fire data inconsistencies, creating a modified PRFD which we use here and make available as Supplement, (d) explore some basic temporal and completeness properties of the data. We find that the dataset's minimum measured burnt areas have changed with time between AF = 0.1 ha (1980–1990), AF = 0.01 ha (1991–1992), and AF = 0.001 ha (1992–2005), with varying degrees of completeness down to these values. These changes in minimum area measured are responsible for greater numbers of fires being recorded. A relatively small number of large fires in the PRFD are responsible for the majority of the burnt area. For example, fires with AF > 100 ha represent about 1% of all fire records but 75% of total burnt area. Finally, we consider for each Continental Portugal district and for the 26-yr period, the total number of rural fires and area burnt in forests and shrublands, each normalized by district areas. We find that the highest numbers of fires per unit area are in highly populated districts, and that the largest fraction of burnt area is in forested areas, coinciding with large parcels of continuous forests (predominantly rural and moderately urban areas).

scholarly journals Size of wildfires in the Euro-Mediterranean region: observations and theoretical analysis

2015 ◽  
Vol 3 (2) ◽  
pp. 1203-1230 ◽  
Author(s):  
C. Hernandez ◽  
P. Drobinski ◽  
S. Turquety ◽  
J.-L. Dupuy
Keyword(s):  
Wind Speed ◽  
Percolation Threshold ◽  
Eastern Europe ◽  
Mediterranean Region ◽  
Burnt Area ◽  
Fire Propagation ◽  
Wind Speeds ◽  
The Mediterranean ◽  
Hot Weather ◽  
Burnt Areas

Abstract. MODIS satellite observations of fire size and ERA-Interim meteorological reanalysis are used to derive a relationship between burnt area and wind speed over the Mediterranean region and Eastern Europe. As intuitively expected, the burnt area associated to the largest wildfires is an increasing function of wind speed in most situations. It is always the case in Eastern Europe. It is also the case in the Mediterranean for moderate temperature anomaly. In situations of severe heatwaves and droughts, the relationship between burnt area and wind speed displays bimodal shape. Burnt areas are large for low 10 m wind speed (lower than 2 m s−1), decrease for moderate wind speed values (lower than 5 m s−1 and larger than 2 m s−1) and increase again for large wind speed (larger than 5 m s−1). To explain such behavior fire propagation is investigated using a probabilistic cellular automaton model. The observed relationship between burnt area and wind speed can be interpreted in terms of percolation threshold which mainly depends on local terrain slope and vegetation state (type, density, fuel moisture). In eastern Europe, the percolation threshold is never exceeded for observed wind speeds. In the Mediterranean Basin we see two behaviors. During moderately hot weather, the percolation threshold is passed when the wind grows strong. On the other hand, in situations of severe Mediterranean heatwaves and droughts, moderate wind speed values impair the propagation of the wildfire against the wind and do not sufficiently accelerate the forward propagation to allow a growth of wildfire size.

scholarly journals Spatial and Temporal Distribution of Biomass Open Burning Emissions in the Greater Mekong Subregion

Climate ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 90
Author(s):  
Agapol Junpen ◽  
Jirataya Roemmontri ◽  
Athipthep Boonman ◽  
Penwadee Cheewaphongphan ◽  
Pham Thi Bich Thao ◽  
...  
Keyword(s):  
Fine Particulate Matter ◽  
Temporal Distribution ◽  
Landsat 8 ◽  
Total Biomass ◽  
Burnt Area ◽  
Fire Emissions ◽  
Vegetation Fires ◽  
Agricultural Burning ◽  
Burnt Areas ◽  
Greater Mekong Subregion

Moderate Resolution Imaging Spectroradiometer (MODIS) burnt area products are widely used to assess the damaged area after wildfires and agricultural burning have occurred. This study improved the accuracy of the assessment of the burnt areas by using the MCD45A1 and MCD64A1 burnt area products with the finer spatial resolution product from the Landsat-8 Operational Land Imager/Thermal Infrared Sensor (OLI/TIRS) surface reflectance data. Thus, more accurate wildfires and agricultural burning areas in the Greater Mekong Subregion (GMS) for the year 2015 as well as the estimation of the fire emissions were reported. In addition, the results from this study were compared with the data derived from the fourth version of the Global Fire Emissions Database (GFED) that included small fires (GFED4.1s). Upon analysis of the data of the burnt areas, it was found that the burnt areas obtained from the MCD64A1 and MCD45A1 had lower values than the reference fires for all vegetation fires. These results suggested multiplying the MCD64A1 and MCD45A1 for the GMS by the correction factors of 2.11−21.08 depending on the MODIS burnt area product and vegetation fires. After adjusting the burnt areas by the correction factor, the total biomass burnt area in the GMS during the year 2015 was about 33.3 million hectares (Mha), which caused the burning of 109 ± 22 million tons (Mt) of biomass. This burning emitted 178 ± 42 Mt of CO2, 469 ± 351 kilotons (kt) of CH4, 18 ± 3 kt of N2O, 9.4 ± 4.9 Mt of CO, 345 ± 206 kt of NOX, 46 ± 25 kt of SO2, 147 ± 117 kt of NH3, 820 ± 489 kt of PM2.5, 60 ± 32 kt of BC, and 350 ± 205 kt of OC. Furthermore, the emission results of fine particulate matter (PM2.5) in all countries were slightly lower than GFED4.1s in the range between 0.3 and 0.6 times.

scholarly journals On the Use of Satellite Sentinel 2 Data for Automatic Mapping of Burnt Areas and Burn Severity

2018 ◽  
Vol 10 (11) ◽  
pp. 3889 ◽  
Author(s):  
Rosa Lasaponara ◽  
Biagio Tucci ◽  
Luciana Ghermandi
Keyword(s):  
Model Development ◽  
Fire Effects ◽  
Mitigation Strategies ◽  
Decision Makers ◽  
Burn Severity ◽  
Burnt Area ◽  
Local Index ◽  
Information Translation ◽  
Burnt Areas ◽  
Sentinel 2

In this paper, we present and discuss the preliminary tools we devised for the automatic recognition of burnt areas and burn severity developed in the framework of the EU-funded SERV_FORFIRE project. The project is focused on the set up of operational services for fire monitoring and mitigation specifically devised for decision-makers and planning authorities. The main objectives of SERV_FORFIRE are: (i) to create a bridge between observations, model development, operational products, information translation and user uptake; and (ii) to contribute to creating an international collaborative community made up of researchers and decision-makers and planning authorities. For the purpose of this study, investigations into a fire burnt area were conducted in the south of Italy from a fire that occurred on 10 August 2017, affecting both the protected natural site of Pignola (Potenza, South of Italy) and agricultural lands. Sentinel 2 data were processed to identify and map different burnt areas and burn severity levels. Local Index for Statistical Analyses LISA were used to overcome the limits of fixed threshold values and to devise an automatic approach that is easier to re-apply to diverse ecosystems and geographic regions. The validation was assessed using 15 random plots selected from in situ analyses performed extensively in the investigated burnt area. The field survey showed a success rate of around 95%, whereas the commission and omission errors were around 3% of and 2%, respectively. Overall, our findings indicate that the use of Sentinel 2 data allows the development of standardized burn severity maps to evaluate fire effects and address post-fire management activities that support planning, decision-making, and mitigation strategies.

scholarly journals A Cautionary Note Regarding the Use of Cumulative Burnt Areas for the Determination of Fire Danger Index Breakpoints

2019 ◽  
Vol 28 (3) ◽  
pp. 254 ◽  
Author(s):  
F. Pimont ◽  
J. Ruffault ◽  
N.K. Martin-StPaul ◽  
J.-L. Dupuy
Keyword(s):  
Fire Danger ◽  
Fuel Moisture ◽  
Cautionary Note ◽  
Burnt Area ◽  
Research Fields ◽  
Fire Activity ◽  
Burnt Areas ◽  
Fuel Moisture Content ◽  
The Relationship

Identifying the links between fire danger metrics and fire activity is critical in various operational and research fields. A common methodology consists in analysing the relationship between cumulative burnt areas and fire danger metrics. Building on this approach, it has been proposed that fuel moisture content (FMC) drives fire activity in some ecosystems through between one and three breakpoints corresponding to the onset or saturation of fire activity. We demonstrate, through two different approaches, that this methodology is incorrect, because it is biased by the frequency distribution of FMC values. From comparison with a neutral fire distribution and correction for the frequency bias, we show that cumulative burnt area breakpoints are spurious: an upper breakpoint might exist (but would be higher than expected), while no evidence of reduced fire danger was detected for the lowest values of FMC (on the contrary, a secondary increase was detected). Our findings clearly suggest that previous breakpoints resulting from this methodology should be considered with caution, as erroneous conclusions regarding fire danger breakpoints could have major consequences for both fire safety and science outcomes. Finally, we discuss widespread confusion between fire danger breakpoints and fire danger levels, which explains most previous erroneous conclusions.

scholarly journals BURNT AREA DETECTION USING MEDIUM RESOLUTION SENTINEL 2 AND LANDSAT 8 SATELLITES

2020 ◽  
Vol XLIII-B5-2020 ◽  
pp. 131-137
Author(s):  
D. Ongeri ◽  
B. K. Kenduiywo
Keyword(s):  
Forest Disturbance ◽  
Hot Spot ◽  
Google Earth ◽  
Landsat 8 ◽  
Burnt Area ◽  
Resource Management System ◽  
Medium Resolution ◽  
The Difference ◽  
Fire Information ◽  
Sentinel 2

Abstract. Forest fire is one of the most serious environmental problems in Kenya that influences human activities, climate change and biodiversity. The main goal of this study is to apply medium resolution sensors (Landsat 8 OLI and Sentinel 2 MSI) to produce burnt area severity maps that will include small fires (< 100 ha) in order to improve burnt area detection and mapping in Kenya. Normalized burnt area indices were generated for specified pre- and post-fire periods. The difference between pre- and post-fire Normalized Burnt Ration (NBR) was used to compute δNBR index depicting forest disturbance by fire events. Thresholded classes were derived from the computed δNBR indices to obtain burnt severity maps. The spatial and temporal agreements of the Burnt area detection dates were validated by comparing against the MODIS MCD641 500 m products and MODIS Fire Information for Resource Management System (FIRMS) 1 km daily product hot-spot acquisition dates. This approach was implemented on Google Earth Engine (GEE) platform with a simple user interface that allows users to auto-generate burnt area maps and statistics. The operational GEE application developed can be used to obtain burnt area severity maps and statistics that allow for initial accurate approximation of fire damage.

scholarly journals Applicability of the MultiTemporal Coherence Approach to Sentinel-1 for the Detection and Delineation of Burnt Areas in the Context of the Copernicus Emergency Management Service

2019 ◽  
Vol 11 (22) ◽  
pp. 2607 ◽  
Author(s):  
Uxue Donezar ◽  
Teresa De Blas ◽  
Arantzazu Larrañaga ◽  
Fermín Ros ◽  
Lourdes Albizua ◽  
...  
Keyword(s):  
Emergency Management ◽  
Incidence Angle ◽  
European Space Agency ◽  
Optical Data ◽  
Mountainous Area ◽  
Management Service ◽  
Burnt Area ◽  
Area Index ◽  
Optical Imagery ◽  
Burnt Areas

In the framework of the Copernicus Emergency Management Service (EMS) Mapping Validation, the applicability of the MultiTemporal Coherence (MTC) technique using Sentinel-1 data and the software made available by the European Space Agency (ESA), the Sentinel Application Platform (SNAP), for the detection and delineation of burnt areas was tested. The main purpose of the study was to test a methodology that would benefit from the advantages of delineating burnt areas based on radar data with respect to optical data due to its capacity to acquire data both night and day and to avoid the interference of clouds and/or smoke. Moreover, the study aimed to acheive the delineation of the burnt areas using Sentinel-1 and SNAP in the frame of an emergency mapping where processing time is constrained due to the necessity of giving a quick response to the emergency. Four Sentinel-1 images were acquired over a mountainous area mainly covered by Mediterranean vegetation that suffered from massive forest fires in the summer of 2016. The burnt area delineation was obtained by an object-based image analysis (OBIA) of the resulting MTC image followed by a visual inspection. The effects of the polarization, the acquisition mode, and the incidence angle of the synthetic aperture radar (SAR) imagery were studied in order to assess the contribution of these sensor varaibles on the results. Results of the Sentinel-1 based delineation were compared to those using optical imagery, which is traditionally used for this application. Therefore, the fire delineation that was derived was compared to that derived using three optical images: pre- and post-event Sentinel-2 images and a post-event SPOT 6 image. The first two were used to calculate the differences of the burnt area index (dBAI), used to derive the burnt area delineation by OBIA and photo interpretation with the help of the SPOT 6 image. Results of the comparison showed the feasibility of using the MTC technique for burnt area delineation, as high overall accuracy values were observed when compared to the burnt area delineation derived from optical imagery. The importance of the incidence angle of the Sentinel-1 images was assessed as well, with lower angles resulting in higher overall accuracies. In addition, the availability of double polarization of the Sentinel-1 images, allowed us to give recommendations regarding which polarization gave the best results. The potential for the use of SAR data, obtaining equivalent results to those obtained from optical imagery, is significant in an emergency context given that radar sensors acquire images continuosly and in all weather conditions.

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