Abstract

There are a limited number of ground-based hydro-meteorological observation networks in developing countries. However, precipitation estimates can be obtained using aeronautical and remote sensing techniques, and from radiometric observations by satellites with a suitable coverage. In this research, Tropical Rainfall Measuring Mission- TRMM Microwave Imager (TRMM-TMI) data are applied to estimate and investigate the surface, convective, and strati form rain rates using an analysis of surface and cloud liquid water, cloud ice, precipitation water, and precipitation ice in 14 vertical atmospheric levels(from the surface to 18 km above the surface). The TRMM-TMI data has a monthly temporal resolution and 0.5° spatial resolutions, and covers the period 1998-2005 in a binary format. Results show that surface precipitation estimated from TRMM-TMI has the greatest correlation with ground-based data for spring and autumn, but overestimates precipitation rates in the winter, spring, and summer. It was also found that convective and strati form precipitation patterns are the same in autumn and winter over Iran, but are different during the spring and summer seasons, and that most of the surface precipitation is related to convective precipitation. Furthermore the height of the melting level is estimated to be 3-4 km above the surface of the country.

Keywords: TRMM-TMI; Convective and strati form precipitation; Water and ice content; Liquid water and ice precipitation; Satellitebased data; Ground-based data