7th Workshop on Forest Fire Management - EARSeL, European ...

3 - Methodology
Effects of fire on surface energy fluxes in a Central Spain Mediterranean forest 147
The model used is based on the Energy Balance Equation:
R n = G + H + LE (1)
where R n (W m -2 ) is the net radiation flux, G (W m -2 ) is the soil heat flux,
H (W m -2 ) is the sensible heat flux, and LE is the latent heat flux or evapotranspiration.
LE can be obtained as a residual of equation (1) if H, G, and
R n are previously known. Detailed description of the guidelines to estimate
every single surface energy flux at both instantaneous and daily scales, as
well as the processing and treatment of the satellite images, can be seen
in Sánchez et al. (2008b).
4 - Results
4.1 - Comparison with observed fluxes
Merging the satellite information with values of air temperature, wind
speed and global radiation, the data set we need is completed. Figure 2
shows, as an example, H and LE maps generated from the 28 September
2007 image. Three of the five scenes in the present study are concurrent
with ground flux measurements. A good agreement is shown between predicted
and observed fluxes. To sum up, relative errors of 6, 12, 20, and 30%
are obtained for R n ,G, H, and LE, respectively.
(a) (b)
Figure 2 - Maps from L5-TM image for the 28 September 2007: (a) H (W m -2 ), (b) LE (W m -2 ).