The estimation of moisture over Egypt from Meteosat satellite observations

Abstract

In Egypt their are 77 ground stations for recording the meteorological elements, but very rare number of these stations cover the desert, while the desert covers 97% of the total land of Egypt. For that, estimation of meteorological data over the desert from Meteosat observations is very interested for the national programs for the desert development. We selected seven ground stations, each one of them represents a specific climatic region in Egypt, for a correlation analysis between the water vapour absorption observed by Meteosat in the spectral band (5.7–7.1 μm) and evaporation and relative humidity measured at these seven ground stations for the period (1985–1986). The correlation coefficients are good for the evaporation, and acceptable for the relative humidity. Also, a correlation analysis of cloudiness observed by Meteosat in the thermal spectral band (10.5–12.5 μm) with surface infra-red measurements at Cairo and Aswan for the period (1990–1992) was performed. The correlation coefficients are good for Cairo, but a weak for Aswan. The infra-red measured from ground by Eppley Precision Infrared Radiometers for the period (1990–1992) have excellent correlation with the air temperature at Cairo and Aswan. Also, there is a good correlation with water vapour at Cairo, but a weak correlation for Aswan. Similar we found a good correlation with cloudiness observed from ground at Cairo, and weak for the observations at Aswan. Models and empirical relations for estimating the moisture over Egypt from Meteosat observations are deduced and tested.