The knowledge of the spatial distribution of biophysical parameters related to the surface energy balance, such as surface albedo and surface temperature, is of great interest for various applications, such as the modelling of atmospheric behaviour and the monitoring of water resources. Satellite-based remotely-sensed data may provide an important contribution in the estimation of energy fluxes, at the surface-atmosphere interface, through the determination of biophysical parameters in a distributed way. In this study the determination of actual evapotranspiration is estimated as a key input to the hydrological balance at catchment scale. The experiment was conducted using high resolution satellite data of Landsat Thematic Mapper in an high mountainous catchment (Valmasino) of the Italian Alps. The watershed surface covers an area of 188 km2 and elevation ranges from 250 m to 3650 m, including different land cover types from prairie to forest. Remotely-sensed images were integrated with ground based meteorological measurements and with a Digital Elevation Model in a GIS environment to salve latent heat flux as residual term of the one-dimensional surface energy balance equation. Daily values of evapotranspiration, estimated from spatially distributed instantaneous latent heat fluxes, are compared with daily rate of actual evapotranspiration computed according to the Priestley-Taylor and Penmann-Monteith methods.
The use of remotely sensed data for the estimation of energy balance components in a mountainous catchment
Brivio PA;
2001
Abstract
The knowledge of the spatial distribution of biophysical parameters related to the surface energy balance, such as surface albedo and surface temperature, is of great interest for various applications, such as the modelling of atmospheric behaviour and the monitoring of water resources. Satellite-based remotely-sensed data may provide an important contribution in the estimation of energy fluxes, at the surface-atmosphere interface, through the determination of biophysical parameters in a distributed way. In this study the determination of actual evapotranspiration is estimated as a key input to the hydrological balance at catchment scale. The experiment was conducted using high resolution satellite data of Landsat Thematic Mapper in an high mountainous catchment (Valmasino) of the Italian Alps. The watershed surface covers an area of 188 km2 and elevation ranges from 250 m to 3650 m, including different land cover types from prairie to forest. Remotely-sensed images were integrated with ground based meteorological measurements and with a Digital Elevation Model in a GIS environment to salve latent heat flux as residual term of the one-dimensional surface energy balance equation. Daily values of evapotranspiration, estimated from spatially distributed instantaneous latent heat fluxes, are compared with daily rate of actual evapotranspiration computed according to the Priestley-Taylor and Penmann-Monteith methods.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
