A model for the estimation of precipitable water

A model has been developed for the estimation of precipitable water on clear days based on the daily and hourly measurements of global I.R. solar radiation and on humidity data taken at ground level. The model takes into account the attenuation processes of radiation by watervapour. The results concerning precipitable water are compared with those obtained with radiosondes both for daily and hourly intervals, obtaining correlation coefficients higher than those achieved with the equations proposed by Reitan and Smith in which only humidity parameters are used. The model has been applied to three periods: cold (October-March), warm (April-September) and annual (January-December) over 3 years in Salamanca (central N-WS pain).