Estimation of daily mean air temperature from MODIS LST in Alpine areas|
Angelo Colombi, Carlo De Michele, Monica Pepe and Anna Rampini
This study is aimed at demonstrating the
feasibility of the MODIS Land Surface Temperature (LST) product as a source for calculating spatially distributed
daily mean air temperature to be used as input for hydrological or environmental
models. The test area is located in the Italian Alpine area. The proposed
procedure solves, by empirical approaches, the problem of relating LST to the Air Temperature (Tair)
and instantaneous Tair
values to daily mean values, exploiting ground data weather station
measurements as a reference. The relationship between LST and Tair
is determined by correlation analysis and equation generalisation for spatial
distribution. The extrapolation of daily mean values of Tair from
instantaneous values is addressed again by correlation analyses taking into
account the altitude variability and exploiting historical series. Validation
was accomplished by accuracy assessment procedures both punctual and spatially
distributed, the latter performed by comparison with the Inverse Distance
Weighting (IDW) interpolation method.
The proposed methodology produced satisfactory
results as related to the objective: The daily mean air temperatures derived by
LST showing an overall RMSE of 1.89°C, and slightly outperforms
the interpolation method used as comparison.
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Submitted: 19 Oct 2006
Revised: 13 Feb 2007
Accepted: 20 Feb 2007
Published: 07 May 2007
Responsible editor: Robin Vaughan
Colombi A, C De Michele, M Pepe & A Rampini, 2007.
Estimation of daily mean air temperature from MODIS LST in Alpine areas.
EARSeL eProceedings, 6(1): 38-46