Geoscience Reference
In-Depth Information
This index has been shown to detect historic fi re scars as old as 10-15 years (Gerard
et al., 2003; Balzter et al., 2005; George et al., 2006). An example of a burned area
map of Central Siberia is shown in fi gure 19.2. This map was used in an integrated
full greenhouse gas accounting system in the European project SIBERIA-2.
The method for estimating fi re radiative power and integrating it to fi re radiative
energy is based on the 4
m mid-infrared channels. The basic concept
is that an active fi re radiates heat, which is being measured by the 4
μ
m and 11
μ
m channel
and contrasted to the background radiances that would have been expected without
a fi re. The choice of the 4
μ
m spectral
radiance is proportional to the integrated total radiance at all wavelengths for fi res
burning at different temperatures. Thus, based on measuring a single channel, it is
possible to estimate the total heat emitted from the fi re. The radiative power esti-
mates have to be integrated over time and over space within the fi re scar to give
fi re radiative energy estimates. Since the combustion of a quantifi ed amount of
carbon generates a known amount of heat release, fi re radiative energy can be used
to estimate the amount of burned biomass (Wooster et al., 2005). This approach
μ
m wavelength is based on the fact that the 4
μ
Figure 19.2
Forest disturbance map of Central Siberia. The shading indicates the years
in which the largest proportion of the polygon burnt. Redrawn from George, C.,
Rowland, C., Gerard, F. and Balzter, H. (2006) Retrospective mapping of burnt areas
in Central Siberia using a modifi cation of the normalised difference water index.
Remote Sensing of Environment
, 104, 346-59, copyright (2006), with permission from
Elsevier.
