Evolution of evapotranspiration and water stress of oak savanna vegetation in the Iberian Peninsula (2001-2015)

Abstract

The objective of this work is to provide new insights about the effect of soil water deficit on the vegetation of Mediterranean oak savanna. The evolution of evapotranspiration (ET) and vegetation water stress over this ecosystem, in the Iberian Peninsula, has been monitored for fifteen years through the application of a remote sensing thermal-based energy balance model. The Surface Energy Balance System (SEBS) has been applied, on a monthly timescale from January 2001 to December 2015, using input satellite and meteorological reanalysis databases. The model performance has been evaluated under these conditions by comparison with field measurements. The estimation of energy fluxes yielded reasonable agreements with observations (RMSD=14-20 W·m–2 for the radiative fluxes and RMSD=26-29 W·m–2 for the turbulent ones) and have led to characterize the main drought events occurred during the study period, and to quantify their effects on the vegetation coverage and production. The most generalized and severe events (2004/2005 and 2011/2012) and their impact on different vegetation strata, oaks and grasslands, are further analyzed.

Keywords

• evapotranspiración
• balance de energía en superficie
• térmico
• dehesa
• sequía