[GRASS-user] Estimating Albedo from Landsat

Nikos Alexandris nikos.alexandris at felis.uni-freiburg.de
Wed Sep 15 09:45:58 EDT 2010


> # so, here it goes... seems to run fine
> i.landsat.toar band_prefix=landsat_postfire_east_sterea_ellas
> method=uncorrected sensor=5 date=2007-09-05 solar_elevation=52.4986238
> product_date=2007-09-05

> r.info landsat_postfire_east_sterea_ellas.toar.6 -r
> min=203.36601783578
> max=319.083636050686

> No way the min value is true ( 203 K = -70.15 C -- irrational for Greece -
> for the moment! -)

> The max value (319 K = 45.85 C) seems to fit for Greece but not for
> September! Maybe for July/August.

looking at the image/histogram again those min and max are outliers I guess. 
The main body of information starts at ~280 K (6.85 C) and stops at ~307 K 
(33.85 C).

I am not sure how to explain the min < 270 K  (those values lie mostly within 
water bodies), but the max > 310 K areas are burned surfaces (a few days old 
burn scars) which will explain the 45 C (at surface) in a September day in 

So, those values seem rational after all.


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