Investigating Changes of Seasonal Precipitation Concentration of Iran in Recent Half-Century

Document Type : Research Paper

Authors

Abstract

In different regions of the world, numerous studies have been conducted on climate change.
The results of those studies show the changes in climatic factors, especially in precipitation and
temperature. Investigation of the precipitation phenomenon as one of the most important
meteorological factors has a special importance in the availability of the water resources. In this
study, using the precipitation concentration index in a seasonal scale, the variations of this
important phenomenon in Iran, were investigated. Using the monthly rainfall time series data of 25
synoptic stations in Iran during 1961-2010, the precipitation concentration index values were
extracted in the seasonal scale. The data were evaluated in two sub-intervals of 25 years. The
significance of the mentioned index in two sub-intervals was analyzed using t-test. The seasonal
trend of the precipitation time series and the precipitation concentration seasonal index were
investigated using the Mann – Kendall test. The zonation results of precipitation concentration
index showed that the distribution of the precipitation in the both sub-intervals obeyed the same
pattern. The mentioned index in the south and central provinces of Iran having the low precipitation
such as Kerman, Yazd, Sistan and Baluchistan had high values. In general, the results showed that
according to the mentioned index, Iran's territory could be divided into three parts (from the view
point of precipitation concentration pattern): the North area and Caspian Sea shores as the first part
having the moderate density and pattern of rainfall, central as the second part having the irregular
pattern of precipitation and the Oman Sea and the Persian Gulf margins having a highly irregular
pattern of rainfall.

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References

منابع مورداستفاده
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Water and Soil Science
Volume 26, 2-2
September 2016
Pages 111-123

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