Precipitable Water and Its Relationship to Surface Dew Point and Vapor Pressure in Athens

Abstract

Abstract The relationship between the total amount of precipitable water and surface dew point and the square root of surface vapor pressure have been examined in Athens on the basis of mean monthly values. The correlation coefficients and linear regression equations have been defined from mean monthly values of precipitable water, surface dew point and vapor pressure for the period 1957 through 1971 and for 0000 and 1200 GMT radiosonde ascents. The monthly correlation coefficients range from −0.36 to 0.98 and seasonal values from 0.39 to 0.97. The correlation coefficients are low in late spring and summer and high in winter; their values at 1200 GMT are in general higher than those at 0000 GMT. The variation of the correlation coefficient with time and season is attributed to climatological conditions and synoptic situations related to different vertical mixing effectiveness.