TAHEREH ENSAFI Moghadam - Research educator, Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran

In discussing the climate of the arid regions, that warming energy supply at the earth’s surface is excessive and rainfall is deficient ,one needs some comparative measure of aridity. The purpose of constructing an Index or a model may be manifold. One such purpose is climatic assessment for proneness of area toward aridity which necessitates various precautions. Hence we might expect an Index of aridity measuring. In this investigation has been used ACI . This quantity ,is the aridity climate Index ratio, that has accounted by Z scores{ } .Present study has assessed Salt Lake Basin of Iran through various statistical analyses and application of an index. In this respect, this investigation can indicate importance of the intraction between climate and desertification. This index suggest climatic effects on aridity and it is one of most suitable criteria for determining the climatic aridity intensity and spreading. In this paper , has been explored the climatic stresses that underline the precipitation and temprature , has been obtained a criteria under title: Aridity Climatic Index by use of statistic and drawing methods including collection, communication, correlation, regression line, data generation, and components analyses of meteorological information, used about 35 stations that have 40 years records from 1957 to 1996. Based on this index, and its classification and 45 output maps ,desertified limited in climatic respect, has been determined in manner from year to year by GIS and ILWIS software application. Too ,the percent of aridity zones of dry-lands in Salt Lake Basin of Iran every year of one long term ,has been accounted by ILWIS software .The Conclusion of this investigation indicates in climatic respect, the Salt Lake Basin of Iran is leading towards climatic aridity.

Aridity variability, Aridity Climatic Index, Z scores, ILWIS software, Salt Lake Basin of Iran)