نوع مقاله : علمی -پژوهشی
نویسندگان
1 دانشجوی دکتری اقلیم شناسی، دانشگاه لرستان
2 استادیار، دانشکده علوم زمین، دانشگاه شهید بهشتی
3 استادیار، گروه جغرافیای طبیعی، دانشگاه لرستان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Extreme cold and ice ages Are The major risks of climate Usually annually in damages to crops and plants as well. Synoptic statistical analysis to predict the occurrence of frost and before the correct decision, and it helps them to deal with. The study aims to identify and analyze the West Synoptic cold waves, collect data, daily minimum temperature stations during the statistical period 1961 to 2010 for the cold months (December to March) was. Using statistical indicators of long-term mean daily minimum temperature,
Numerical threshold was cold waves and cold waves were identified on the basis of the 56-day combined. Cluster analysis of data and the level of 500 hPa SLP for 56 days, three patterns of atmospheric circulation there. In each model, the main cause of heat waves in the sea level pressure with a central pressure of 1032 hPa core exposure to the northwest, southeast of the North West and West of the country.
The anticyclonic circulation over the top of his loss very cold air over the region. At the level of 500 hPa deep trough is located in the western part of the region which fall within the northern cold air down through the long, cold waves is the main factor. Meridian flow westerly winds and currents of the North Important role in the occurrence of cold temperatures, resulting in the loss of cold air blowing across the top of the West. In most stations gust of cold temperatures aggravated by the high altitude region.
کلیدواژهها [English]
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