Scientific- Research Quarterly of Geographical Data (SEPEHR)

Scientific- Research Quarterly of Geographical Data (SEPEHR)

Comparative analysis of rainfall and drought trend in the Caspian Sea basin

Document Type : Research Paper

Author
Majid Montazeri
Member of faculty, Department of Geography, University of Najafabad
Abstract
In order to assess the climatic drought trend in 23 sub-basins of the Caspian Sea, monthly precipitation data were converted to the zoned data by interpolation method. Then, based on the coordinates of the basins, the monthly precipitation of each basin was separated. The Standard Precipitation Index (SPI) method was used to assess climatic droughts and this index was calculated monthly for each basin. According to the parametric test, linear regression of 23 sub-basins of Caspian Sea in January, May and December do not show any significant trend at 95% confidence level. Five sub basins in the months of February and July have a positive trend and 11 sub basins show negative trend in March and September. By applying non-parametric Mann-Kendall test on the SPI matrix of the 23 Caspian sub basin, it was found that no baseline shows significant trend in May. The highest trend in six sub-basins have been in the months of July and August.
Keywords
Drought
Trend
Rainfall
Standard rainfall index
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Scientific- Research Quarterly of Geographical Data (SEPEHR)
Volume 20, Issue 80
Winter 2012
Pages 23-28