جابجايي مكاني موج هاي زمستاني گرما در ايران

The Displacement Position of Heat Waves During Winter in Iran

Heat waves are the most effective factors on ecosystem during the cold period of a year. Study of this phenomenon is important in Iran because of three geographic characteristics: rainfall deficiency, ependence on drinking water resources to snow reserves, and their duration in high lands. In this paper, we extracted the monthly highest of the temperature during cold period from November to May for 21 weather stations in Iran during 1970 until 2000 from meteorological yearbooks.We determined heat position cores by calculation of Z value for every station during the peak day of every heat wave.Next, location displacement of the highest temperature cores during 31 years as primitive result showed the most of marginal stations (adjacent to water resources such as the Persian Gulf) had the more intense heat cores. Then, when we used heat Z values instead of highest temperatures in our spatial models, heat cores displaced toward internal areas of Iran especially the Zagros and Alborz Mountains. Final results represented mountainous and snowy areas in northwestern, northern, and about western of Iran have the higher positive deviations of temperature in comparison with other areas. This means, snowfield resources in these areas will melt faster and increase sediments in rivers which reduce the water capacity of dams. Therefore, the process of dam construction in these areas should be serious cautiously. In other hand, saving of rainfalls with watershed management is prior to dam construction.