مطالعه و تحليل بادها و جريان هاي هوا در ترازهاي مختلف جو در ماهها و روزهاي بارشي در منطقه شيركوه يزد

The study on winds and upper air currents in different standard levels in rainy days and months in Shir-Kuh region of Yazd

Shortage of water resources is one of the major obstacles regarding sustainable development in Iran and some other countries. In order to handle this situation, precipitation enhancement project can be used as a modern method to solve this problem. In order to perform these projects, a series of scientific research concerning the conditions of different areas should be done to have successful precipitation enhancement projects. Although the main part of these studies are the site selection studies, the scientific bases for PEPs including the climatology of clouds and precipitation, winds and upper air currents in different types of weather having special characteristics in standard levels of the atmosphere, and synoptic and thermodynamic atmospheric conditions are important indicators for air situation such as stability and instability. So studying these factors can provide PEP planners with necessary information. The present research has been performed in Shir- kuh region, using the data of wind and humidity in the upper atmosphere of Bandar Abbass, Kerman and Shiraz stations and the earthʹs surface wind data of kerman ,Bandar Abbass, Baft, Yazd and Shiraz synoptic stations. Findings of this research show that the highest frequencies of winds and air flows in standard levels are in the west and south- west of this region, in rainy cold months. In rainy days the prevailing winds at the surface are between 170° - 360° and more than 80 percent of the winds blowing in the western regions are at the 700 Hpa level. In the same rainy days, the direction of the prevailing winds in the middle and upper levels of atmosphere in these stations is between 180°-330°. Considering the direction of south and south -west and even south-east winds in rainy days and the fact that they receive heat and humidity while passing the south waters and strike the southern slops of the mountains, when they enter centeral Iran and shir- kuh, they can play an important role in increasing instability and precipitation. The above mentioned positive points are very important in forecasting the rainy days in order to challenge the problem of water shortage in this region and to carry out the precipitation enhancement projects as shown in this research.