By Raquel Iniesta Ruiz.
ABSTRACT:
This work presents an approach for the calculation of actual evapotranspiration at a regional scale. Using the daily Penman-Monteith equation, the reference evapotranspiration has been estimated by means of a combined model from meteorological stations data and remote sensing data.
Remote sensing data have been used to estimate surface reflectance, cloudiness factor, net radiation and the crop coefficient through the Relative Greenness Index (RGI). To do that MODIS and SEVIRI-MSG data have been use.
The meteorological data were interpolated by different methods determined by a previous study.
The study has been focused in the Autonomic Community of Andalusia, region located in the South of Spain. The chosen months like period of analysis have been July and August because of the greatest evapotranspiration of the year takes place during them and therefore its calculation gains a great importance.
The result of this study shows the usefulness of MODIS to calculate reference and actual evapotranspiration at regional scale. Furthermore, the RGI is shown as a good indicator for characterizing the evolution of crop coefficient.
Keywords: crop coefficient, evapotranspiration, remote sensing.