Improving global fire carbon emissions estimates by combining moderate resolution burned area and active fire observations

James T. Randerson, UC Irvine, Dept. of Earth System Science, jranders@uci.edu (Presenter)
Yang Chen, UC Irvine, Dept. of Earth System Science, ychen17@uci.edu
Louis Giglio, NASA GSFC / University of Maryland, giglio@hermes.geog.umd.edu
Brendan Rogers, UC Irvine, Dept. of Earth System Science, bmrogers@uci.edu
Hsiao-wen Lin, UC Irvine, Dept. of Earth System Science, hwlin@uci.edu
Guido R. van der Werf, UC Irvine, Dept. of Earth System Science, guido.van.der.werf@falw.vu.nl

In several important biomes, including croplands and tropical

forests, many small fires exist that have sizes that are well below

the detection limit for the current generation of burned area

products derived from moderate resolution spectroradiometers. These

fires likely have important effects on greenhouse gas and aerosol

emissions and regional air quality. Here we developed an approach for

combining 1km thermal anomalies (active fires; MOD14A2) and 500m

burned area observations (MCD64A1) to estimate the prevalence of

these fires and their likely contribution to burned area and carbon

emissions. We first estimated active fires within and outside of 500m

burn scars in 0.5 degree grid cells during 2001-2010 for which

MCD64A1 burned area observations were available. For these two sets

of active fires we then examined mean fire radiative power (FRP) and

changes in enhanced vegetation index (EVI) derived from 16-day

intervals immediately before and after each active fire observation.

To estimate the burned area associated with sub-500m fires, we first

applied burned area to active fire ratios derived solely from within

burned area perimeters to active fires outside of burn perimeters. In

a second step, we further modified our sub-500m burned area estimates

using EVI changes from active fires outside and within of burned

areas (after subtracting EVI changes derived from control

regions). We found that in northern and southern Africa savanna

regions and in Central and South America dry forest regions, the

number of active fires outside of MCD64A1 burned areas increased

considerably towards the end of the fire season. EVI changes for

active fires outside of burn perimeters were, on average,

considerably smaller than EVI changes associated with active fires

inside burn scars, providing evidence for burn scars that were

substantially smaller than the 25 ha area of a single 500m pixel. FRP

estimates were also lower for active fires outside of burn

perimeters. In our analysis we quantified how including sub-500m

burned area influenced global burned area and carbon emissions in

different continental regions using the Global Fire Emissions

Database (GFED) biogeochemical model. We conclude by discussing

validation needs using higher resolution visible and thermal imagery.

Presentation Type:  Poster

Session:  Coupled Processes at Land-Atmosphere-Ocean Interfaces   (Mon 4:00 PM)

Associated Project(s): 

• Randerson, Jim: Global Carbon Emissions from Fires: Improving our Understanding of Interactions between Land Use, Fires, and Climate Change ...details

Poster Location ID: 70