Spatial distribution of the daily precipitation concentration Index inside the Northwest of Iran

The consequences of climate change in drought areas such as Iran, temporal and spatial changes are the distribution and concentration of rainfall, which can affect water resources. On the other hand, increasing the concentration of rainfall can causing hazards such as floods . The importance of the issue of distribution and concentration of rainfall has encouraged researchers to study in this regard. Concentration Index (CI) is a method which is used to study the distribution and concentration of rainfall. This study was performed to calculate and analyze 23 station daily precipitation concentration index in Northwest of Iran during 1951 to 2015. In this research range of CI values calculated between 0.57 for Khoy station to 0.67 for Maku station and average 0.61 for all station. CI map obtain from values Interpolation and showed that the Northwest part of the study area with Maku station depute, compared to other regions, especially in central areas such as Tabriz station is not uniformly distributed. Also Northwest area with an average of 0.61 compared with an average CI of Iran ( 0.64) is more evenly precipitation distributed throughout the year.