نویسندگان
1 دانشیار
2 دانشجوی دکترا
3 کارشناسی ارشد
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Atmospheric circulations are very changeable. This changes lead to appearance of the weather patterns and forms of atmospheric flows which occur in different time scales. Teleconnection patterns represent major changes that occur in the atmospheric wave patterns and jet streams and contributes to the patterns of temperature, precipitation, storms track and especially on operation of remote climate in a vast realm. Thus, according to the procedure of the teleconnection pattern, in this paper, data on sea level pressure fluctuations in North Atlantic and annual precipitation of Fras province over a period of 28 years (1978-2005) was considered. Then by fitting appropriate distribution to the annual precipitation (Gamma distribution), the SPI index was calculated for each years and relationship between SPI index and positive – negative phases of NAO were assessed in different delays. The results of this study showed that, between droughts of Fras province and NAO phases simultaneously, there is only a significant relationship in Abadeh station and there is no significant relationship between in the other stations. Finally, in order to understand the large scale climate signals associated with more remote areas (Fras province), relationship between the droughts and positive – negative NAO phases were investigated at different monthly delays. As was seen, Abadeh station is devoted itself most of the time all delays in 1, 2 and 3 months, and the lowest frequency of correlation with the NAO was observed in Kazeroun station. The total, in all stations at different delays, May (Ordibehesht) has the greatest harmony with the NAO index.
کلیدواژهها [English]