METHODS FOR ESTIMATING VAPOR-PRESSURE DEFICIT AT A REGIONAL-SCALE DEPENDING ON DATA AVAILABILITY

In this work, a study was carried out to develop and evaluate several methods for estimating the daily vapor pressure deficit (VPD) at therm o-pluviometric stations (weather stations in which only temperature an d precipitation are measured) located in a region with a homogeneous c limate where there is at least one complete meteorological station. Fo ur estimation methods were compared with the method of calculation pro posed by the FAO used in the equations for calculating evapotranspirat ion (ET), which was considered as a reference. From the analysis of th e operability of each method depending on the availability of data and on the results obtained, it is concluded that the method proposed for estimating the vapor pressure deficit in climatic zones where there i s little meteorological information is quite reliable, and that it can , therefore, be used as an input in empirical equations that need to k now the VPD for calculating ET. (C) 1997 Published by Elsevier Science B.V.