The Variation of Annual Precipitation and Precipitation Concentration Index of Iraq

Abstract

The shortage of water and the increasing temperature have an effect on the distribution and the amount of rainfall. The long-term of dry or wet season is showed in this paper through Run Theory using monthly precipitation data of 29 stations in Iraq that are divided into three zones for30 years from 1980 to 2010 in order to understand the behavior of precipitation. The annual precipitation of Mosul, Amara and Diwaniya stations fluctuated between dry and wet years. Also, the number of dry years is larger than the number of wet years for the three zones of Iraq. In the northern zone, the longest dry succession years are found in Sinjar with 24.3% and Teleafer 23.1%, while the longest wet succession years found in Makhmoor with 18.5% of the total annual precipitation over the study period. In the middle zone, the longest dry and wet succession years are found in Khahlis and Heet stations with 23.8% and 15.6% of total annual precipitation over the period respectively. At least, in the southern zone, the longest dry succession years is found in Rutba station with 30.7% stations of the total annual precipitation over the study period which is the longest dry succession of all and the longest wet succession period was in Samawa station with 48.7% of total annual precipitation over the period. On the other hand, the precipitation concentration index was calculated for each station throughout study period and it varies between less and more than 16 referring to that the precipitation doesn't have a uniform distribution and sometimes irregular or strong irregular distribution, thus, the study area is divided into two zones: moderate precipitation concentration zone which has a range of PCI 16 zone exceptionally, Biji, AL-Hai and Samawa stations. Keywords - Run theory, Precipitation, Dry season, Wet season, Iraq