نوع مقاله : مقاله پژوهشی
نویسندگان
ندارد
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Authors have studied the precipitation fluctuations and rainfall changes in
Ahar synoptic station in this paper, applying long term monthly records for the
47 year period (1960-2006). Results of using Man-Kendal test indicate
significant correlation between precipitation changes and tele-connection
patterns in the study area. With regard to this matter, the relationship of autumn
precipitation with El-Nino atmospheric-oceanic pattern (so-called ENSO) during
warm phase increases precipitation and the same linkages with La-Nina during
cold phases enhances droughts. The correlation of winter precipitation with teleconnection
patterns of Northern Atlantic and Arctic Ocean has been also
significant in such a way that during the North Atlantic negative phases the
magnitude of incoming cyclones to the area creates higher rates and on the other
hand, in positive phase causes a decrease in precipitation due to the dominance
of Azure Anticyclone. Testing of Standardized Precipitation Indexes (SPI) for
evaluating monthly wet and dry periods also indicates that the occasional
occurrence of drought periods in the area is irreversible. The independence of
monthly wet and dry periods is also one of the main results of this study.
کلیدواژهها [English]
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