â â â  this paper attempts to investigate the relationship between 500hpa circulation patterns and weather types (coldest, warmest and raining) over 16 synoptic stations of mountainous region of iran. the mountainous region of iran covers about 670000 square kilometer (41 percent) of iran. in this paper have been investigated the relationship between circulation patterns in 500hpa level with we...

1. introduction variability and changes in precipitation amounts, including extreme precipitation and droughts, trigger relevant societal and environmental impacts. atmospheric circulation strongly determines precipitation variability over southern half of iran. the influence of prevalent synoptic situations on the distribution of precipitation amounts needs to be understood, as well as their f...

there are a number of ideas to generate cloud and precipitation in the southern coasts of caspian sea, but none of them explain the cause of precipitation particularly heavy and super heavy precipitations precisely. this study describes main thermodynamic factors when the situation and location of synoptic patterns are effective. on the basis of daily data, monthly regimes and monthly trends of...

â â â  in this study, ability and skill of the nesting version of the regcm3 regional climate model in simulation of monthly and seasonal amount of precipitation and temperature using four different cumulus parameterization of grell-as, grell-fc, emanuel and kuo have been studied over khorasan area including three provinces of north khorasan, khorasan razavi and south khorasan. in this regards,...

climate change is a phenomenon that has made the most concern in communities and decision making centers. this phenomenon has important effects on different aspects of human life. one of the most important crops that are affected by climate change is wheat. accordingly, data and information of northern khorasan have been used to study the effects of climate change on rain-fed wheat yield. for t...

introduction climate is a system consisting of atmosphere, lithosphere, cryosphere, hydrosphere, and biosphere. this system is involved in the exchange of energy and moisture among these five components. the exchanges link the atmosphere as the central component of the climate to other spheres. changes do not occur separately in this system; rather change in one component contributes to reactio...

Past climatological research has not quantitatively defined the synoptic-scale circulation deviations responsible for anomalous summer-season precipitation totals in the southeastern United States. Therefore, the objectives of this research were to determine the synoptic-scale controls of wet and dry multiday periods during the summer within a portion of the southeastern United States as well a...