Spatial patterns and temporal varability of drought in western Iran

نویسندگانRaziei, T - Saghafian, B - Paulo, A.A - Pereira, L.S - Bordi, I
نشریهWater Resources Management
ارائه به نام دانشگاهTechnical and Engineering Department, Science and Research Branch Islamic Azad University
شماره صفحات439-455
شماره مجلد23
ضریب تاثیر (IF)5.120
نوع مقالهFull Paper
تاریخ انتشار2009
رتبه نشریهISI
نوع نشریهچاپی
کشور محل چاپایالات متحدهٔ امریکا

چکیده مقاله

An analysis of drought in western Iran from 1966 to 2000 is presented using monthly precipitation data observed at 140 gauges uniformly distributed over the area. Drought conditions have been assessed by means of the Standardized Precipitation Index (SPI). To study the long-term drought variability the principal component analysis was applied to the SPI field computed on 12-month time scale. The analysis shows that applying an orthogonal rotation to the first two principal component patterns, two distinct sub-regions having different climatic variability may be identified. Results have been compared to those obtained for the large-scale using re-analysis data suggesting a satisfactory agreement. Furthermore, the extension of the large-scale analysis to a longer period (1948–2007) shows that the spatial patterns and the associated time variability of drought are subjected to noticeable changes. Finally, the relationship between hydrological droughts in the two sub-regions and El Niño Southern Oscillation events has been investigated finding that there is not clear evidence for a link between the two phenomena.

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