آب و فاضلاب (Jun 2005)
Annual Rainfall Trend Analysis in Arid and Semi-arid Regions of Central and Eastern Iran
Abstract
Climate variability is the main reason for drought and water scarcity. Annual rainfall trend was investigated in arid and semi-arid regions of Iran using 79 climatology and synoptic stations with 36 years of data records. Monthly and annual precipitation data from homogeneity tests were applied and discontinuities were adjusted in non-homogeneous stations using the annual nonparametric Mann-Kendal statistic test. The results showed no evidence of climate change in the study area. Although many stations showed negative trends indicating decreasing precipitation, this trend was not statistically significant at 95 percent significant level. The results indicate that the southeastern part of Iran has recently experienced a climate change of negative precipitation trend. Mapping trend statistics did not show any geographical orientation. Considering the global warming and rising temperatures, evident in the study area, the adverse effects of decreasing precipitation on temperature, the adverse effects of decreasing precipitation in conjunction with significant positive trends in temperature rise may lead to severe ecological and economic problems in the study area. The frequently occurring droughts in this region can be due to increasing temperature and decreasing precipitation.
