3rd HyMeX workshop 1-4 June 2009 Heraklion (Gournes), Crete-Greece
Study and calibration of a surface evaporation scheme for time series of climate variables in a mediterranean sitePaolo Martano (ISAC-CNR)
Simple schemes for the surface evapotranspiration flux, depending on few locally tuned parameters, may be used in regional climate studies of surface water balance if applied to long-term time series or statistically downscaled meteorological variables.
A possible scheme is proposed, mainly based on the Penman-Monteith equation with a surface resistance varying with the local hydrometeorological conditions and depending on a restricted number of parameters. In the present case of a partially vegetated Mediterranean area the surface resistance is expressed as a parallel between a bare soil resistance and a canopy resistance, with 3 unknown parameters tuning the two mentioned resistance components and the surface roughness respectively. A calibration is then attempted by an inverse parameter estimation method using a local data set above partially vegetated terrain in southern Italy. The data set is extracted from a real-time updating web archive of micrometeorological data of land-atmosphere transfer measurements, that is in ongoing construction (www.basesperimentale.le.isac.cnr.it) and will be also a contribution to HyMeX WG2.