كليدواژه :
درياچه نمك , خشكسالي , شاخص بارش ميانگين , شاخص درصد از بارش ميانگين
چكيده لاتين :
Arid and semi-arid areas occupied a major part of Iran. These zones not only face with precipitation deficiency but also are affected by annual fluctuations. In arid and semi-arid regions, human activities are also affected by the most specific climatic characteristic, i.e., precipitation shortage. The lower than long-term precipitation rates which are called drought or dry periods, can cause various anomalities. In order to study the climatic characteristics in any region, it is necessary to analyze spatio-temporal occurrence of atmospheric features in a framework of climatic classification; and the attempts of researchers like Koppen, Amberget, Thornthwaite and Peggy are good evidences of the importance of such issues.
Using precipitation indexes and precipitation percentages, we have analyzed and interpreted the 1970-2000 period precipitation characteristics of 8 stations located in Salt Lake Basin. Afterwards, we have used diagrammatic methods and exponential models for wet and dry period estimations. This is followed by the determination of dry and wet period changes relative to their amounts on semi-logarithmic diagrams and finally, the estimation of regression equations. Subsequently, we have applied average precipitation and percentage of average precipitation indexes for the calculation of mean aridity degrees, compared with dry and wet periods. The results of this study help recognize the aridity intensity at different stations of the study area in Salt Lake Basin, namely denoted as: semi-arid, arid with lower intensity and arid with higher intensity, and accordingly, the climatic classification is also accomplished.
