Trend analysis of rainfall and effect of it on water resources in Iran

Long-term trends in annual and monthly rainfall amount collected at 33 synoptic stations in Iran are investigated in this study because of study on climate change and effect of it on water resources. The statistical significance of trend and climate variability is assessed by the Mann-Kendall test. The trend analysis and the Mann-Kendall test indicate that there are no significant trends in monthly rainfall for most of the synoptic stations in Iran. However, the maximum number of stations with negative trends have been observed in April (29 stations) but with positive trends in December (26 stations). The significant trends, in annual rainfall have been noticed only at five synoptic stations. Rainfall decrease in water necessity months have major impacts on hydrological cycles and consequently on available water resources. Regard to the negative effects of global warming on water ground level, soil moisture, amount of water on the upper layers of soil and etc,. notice to rainfall and temperature together with trend of other climatic parameters can help to conservation of water resource in the future.

کلیدواژه ها:

Trend ، Mann-Kendall test ، Rainfall ، Climate variability ، Water resources ، Iran