Morfología Fluvial.-Obtención de la conductancia de la vegetación a partir de índices espectrales y temperatura superficial para la estimación de la evapotranspiración en vegetación semiárida

Abstract

This work evaluates the possibilities for estimating stomatal conductance (C) and leaf transpiration (Trf) at the ecosystem scale from radiometric indices and surface temperature. The relationships found between indices and the transpiration component of the water balance in a semiarid tussock ecosystem in SE Spain are discussed. Field data were collected from spring 2008 until winter 2009 in order to observe the annual variability of the relationships and the behaviour of spectral indices and surface temperature. The results showed that best relationships with leaf transpiration were found with the PRI index and the Red-Green ratio (r2 > 0.86 for both), and with the vegetation temperature minus the air temperature (Tc – Ta) (r2= 0.54). For stomatal conductance, several indices showed good agreement (r2 > 0.7) with measurements, TCARI/OSAVI, NDWI, SRWI, R760 / R500 and R800 / R470 indices. These results showed the applicability of remote sensing data to monitor complex ecophysiological variables at field scale.