scholarly journals What shapes fire size and spread in African savannahs?

2021 ◽  
Author(s):  
Sacha Takacs ◽  
Henrike Schulte to Bühne ◽  
Nathalie Pettorelli
Keyword(s):  
Fire Size

Fire frequency is relatively more important than fire size — A reply to Russell-Smith et al

2015 ◽  
Vol 192 ◽  
pp. 478
Author(s):  
Anthony D. Griffiths ◽  
Stephen T. Garnett ◽  
Barry W. Brook
Keyword(s):  
Fire Frequency ◽  
Fire Size

Spatial patterns of fire patch size and shape complexity in the Brazilian savanna

2021 ◽  
Author(s):  
Joana Nogueira ◽  
Julia Rodrigues ◽  
Jan Lehmann ◽  
Hanna Meyer ◽  
Renata Libonati
Keyword(s):  
Land Use ◽  
Shape Index ◽  
Fire Spread ◽  
Core Area ◽  
Validation Dataset ◽  
Burned Area ◽  
Fire Size ◽  
Size And Shape ◽  
The North ◽  
Shape Complexity

<p>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.</p><p><strong>Acknowledges:</strong> 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</p>

scholarly journals Assessing the accuracy of remotely-sensed fire datasets across the Southwestern Mediterranean basin

2020 ◽  
Author(s):  
Luiz Felipe Galizia ◽  
Thomas Curt ◽  
Renaud Barbero ◽  
Marcos Rodrigues
Keyword(s):  
Mediterranean Basin ◽  
Quantitative Estimate ◽  
State Of The Art ◽  
Warm Season ◽  
Burned Area ◽  
Fire Size ◽  
Northern Iberian Peninsula ◽  
Fire Atlas ◽  
Highly Correlated ◽  
Size Threshold

Abstract. Recently, many remote-sensing (RS) based datasets providing features of individual fire events from gridded global burned area products have been released. Although very promising, these datasets still lack a quantitative estimate of their accuracy with respect to historical ground-based fire databases. Here, we compared three state-of-the-art RS datasets (Fire Atlas, FRY and GlobFire) with high-quality ground databases compiled by regional fire agencies (AG) across the Southwestern Mediterranean basin (2005–2015). We assessed the spatial and temporal accuracy in estimated RS burned area (BA) and number of fires (NF) aggregated at monthly and 0.25° resolutions, considering different individual fire size thresholds ranging from 1 to 500 ha. Our results show that RS datasets were highly correlated with AG in terms of monthly BA and NF but severely underestimated both (by 38 % and 96 %, respectively) when considering all fires > 1 ha. Stronger agreement was found when increasing the fire size threshold, with fires > 100 ha denoting higher correlation and much lower error (BA 10 %; NF 35%). The agreement between RS and AG was also the highest during the warm season (May to October) in particular across the regions with greater fire activity such as the Northern Iberian Peninsula. The Fire Atlas displayed a slightly better performance, with a lower relative error, although uncertainty in gridded BA product largely outpaced uncertainties across the RS datasets. Overall, our findings suggest a reasonable agreement between RS and ground-based datasets for fires larger than 100 ha, but care is needed when examining smaller fires at regional scales.

Factors influencing the development of violent pyroconvection. Part I: fire size and stability

2021 ◽  
Author(s):  
Rachel L. Badlan ◽  
Jason J. Sharples ◽  
Jason P. Evans ◽  
Rick H. D. McRae
Keyword(s):  
Fire Size ◽  
Factors Influencing

Design car fire size based on fire statistics and experimental data

2020 ◽  
Vol 44 (8) ◽  
pp. 1099-1107
Author(s):  
Dorota Brzezinska ◽  
Renata Ollesz ◽  
Paul Bryant
Keyword(s):  
Experimental Data ◽  
Fire Statistics ◽  
Fire Size

More Than Emissions and Chemistry: Fire Size, Dilution, and Background Aerosol Also Greatly Influence Near‐Field Biomass Burning Aerosol Aging

2019 ◽  
Vol 124 (10) ◽  
pp. 5589-5611 ◽  
Author(s):  
A. L. Hodshire ◽  
Q. Bian ◽  
E. Ramnarine ◽  
C. R. Lonsdale ◽  
M. J. Alvarado ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Near Field ◽  
Fire Size ◽  
Biomass Burning Aerosol ◽  
Aerosol Aging

scholarly journals Cajander larch (<i>Larix cajanderi</i>) biomass distribution, fire regime and post-fire recovery in northeastern Siberia

2012 ◽  
Vol 9 (10) ◽  
pp. 3943-3959 ◽  
Author(s):  
L. T. Berner ◽  
P. S. A. Beck ◽  
M. M. Loranty ◽  
H. D. Alexander ◽  
M. C. Mack ◽  
...  
Keyword(s):  
Satellite Imagery ◽  
Aboveground Biomass ◽  
Forest Biomass ◽  
Burned Area ◽  
Forest Disturbances ◽  
Biomass Distribution ◽  
Fire Size ◽  
Northeastern Siberia ◽  
Fire Activity ◽  
Larix Cajanderi

Abstract. Climate change and land-use activities are increasing fire activity across much of the Siberian boreal forest, yet the climate feedbacks from forest disturbances remain difficult to quantify due to limited information on forest biomass distribution, disturbance regimes and post-disturbance ecosystem recovery. Our primary objective here was to analyse post-fire accumulation of Cajander larch (Larix cajanderi Mayr.) aboveground biomass for a 100 000 km2 area of open forest in far northeastern Siberia. In addition to examining effects of fire size and topography on post-fire larch aboveground biomass, we assessed regional fire rotation and density, as well as performance of burned area maps generated from MODIS satellite imagery. Using Landsat imagery, we mapped 116 fire scar perimeters that dated c. 1966–2007. We then mapped larch aboveground biomass by linking field biomass measurements to tree shadows mapped synergistically from WorldView-1 and Landsat 5 satellite imagery. Larch aboveground biomass tended to be low during early succession (≤ 25 yr, 271 ± 26 g m−2, n = 66 [mean ± SE]) and decreased with increasing elevation and northwardly aspect. Larch aboveground biomass tended to be higher during mid-succession (33–38 yr, 746 ± 100 g m−2, n = 32), though was highly variable. The high variability was not associated with topography and potentially reflected differences in post-fire density of tree regrowth. Neither fire size nor latitude were significant predictors of post-fire larch aboveground biomass. Fire activity was considerably higher in the Kolyma Mountains (fire rotation = 110 yr, fire density = 1.0 ± 1.0 fires yr−1 × 104 km−2) than along the forest-tundra border (fire rotation = 792 yr, fire density = 0.3 ± 0.3 fires yr−1 × 104 km−2). The MODIS burned area maps underestimated the total area burned in this region from 2000–2007 by 40%. Tree shadows mapped jointly using high and medium resolution satellite imagery were strongly associated (r2 &amp;approx; 0.9) with field measurements of forest structure, which permitted spatial extrapolation of aboveground biomass to a regional extent. Better understanding of forest biomass distribution, disturbances and post-disturbance recovery is needed to improve predictions of the net climatic feedbacks associated with landscape-scale forest disturbances in northern Eurasia.

Calculation of fire spread rates across random landscapes

2003 ◽  
Vol 12 (2) ◽  
pp. 167 ◽  
Author(s):  
Mark A. Finney
Keyword(s):  
Travel Time ◽  
Growth Rates ◽  
Fire Spread ◽  
Harmonic Mean ◽  
Fire Growth ◽  
Fire Size ◽  
Spread Rate ◽  
Fuel Treatments ◽  
Fuel Mixtures

An approach is presented for approximating the expected spread rate of fires that burn across 2-dimensional landscapes with random fuel patterns. The method calculates a harmonic mean spread rate across a small 2-dimensional grid that allows the fire to move forward and laterally. Within this sample grid, all possible spatial fuel arrangements are enumerated and the spread rate of an elliptical fire moving through the cells is found by searching for the minimum travel time. More columns in the sample grid are required for accurately calculating expected spread rates where very slow-burning fuels are present, because the fire must be allowed to move farther laterally around slow patches. This calculation can be used to estimate fire spread rates across spatial fuel mixtures provided that the fire shape was determined from wind and slope. Results suggest that fire spread rates on random landscapes should increase with fire size and that random locations of fuel treatments would be inefficient in changing overall fire growth rates.

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