A Quantitative Study of the Effect of Persian Gulf and Oman Sea as Humidity Sources for Synoptic Systems in Iran

A regional climate model (RegCM3) with horizontal resolution of 40 km in 18 vertical levels, Haltslag global boundary scheme, Grell convection parameterization and Fritsch- Chappell scheme for simulation of mesoscale systems is used for the study of climate of the region in the winter season of "2003-2004". The region concerned extends from 20 to 40 degree north in latitude and from 45 to 65 degree east in longitude, covering Oman Sea and Persian Gulf as arguably the main humidity sources for the synoptic systems. Starting from a control experiment, some specifically designed experiments were performed in which the surface characteristics over the water bodies were changed. Comparison of the model output for monthly accumulated precipitation in the control experiment with the analyzed, observed charts of accumulated precipitation indicates that the model can forecast precipitation reasonably well both temporally and spatially over the region. In different experiments, Persian Gulf and Oman Sea waters were removed, separately and together, in order to find out their individual contributions to the amount of precipitation over the region.

Keywords:

land use change , regional climate model , accumulated precipitation , humidity