The role of blocking in the structure of Mediterranean cyclones which affect Middle-East and Iran

Abstract

W - 90E, 15N - 65N).  The MM5 outputs were investigated by comparing the following physical, dynamical and thermodynamical fields: horizontal components of the wind speed, vertical motion, relative vorticity, potential vorticity, temperature, potential temperature and relative humidity.  Results show that blocking (1) produced a negative anomaly in the zonal and a positive anomaly in the meridional components of wind (2) intensified the relative and potential vorticity and (3) increased vertical motion, relative humidity and precipitation amount.  Furthermore, blocking intensified and increased the life span of the cyclone and changed its direction towards lower latitudes.  Although this subject deals with scales larger than the general soaring scales, it is necessary to first understand the large scales.