Coastal precipitation formation and discharge based on TRMM observations

Abstract

Abstract. The interaction between breezes and synoptic gradient winds creates persistent convergence zones nearby coastlines. The low level convergence of moist air promotes the dynamical and microphysical processes responsible for the formation of clouds and precipitation. Our work focuses on the winter seasons of 1998–2011 in the Eastern Mediterrenean. During the winter the Mediterrenean sea is usually warmer than the adjacent land, resulting in frequent occurence of land breeze that opposes the commom synoptic winds. Using rain-rate vertical profiles from the Tropical Rainfall Measurement Mission (TRMM) satellite, we examined the spatial and temporal distribution of average hydrometeor mass in clouds as a funtion of the distance from coastlines. Results show that coastalines in the Eastern Mediterrenean are indeed favored areas for precipitation formation and discharge. The intra-seasonal and diurnal changes in the distribution of hydrometeor mass indicate that the land breeze is most likely the main responsible mechanism behind our results.