نوع مقاله : مقاله پژوهشی
گروه جغرافیا، دانشکده ادبیات و علوم انسانی ، دانشگاه یاسوج، یاسوج، ایران
عنوان مقاله [English]
In this study, for investigate the length of dry spells in Kohgiluyeh and Boyer-Ahmad provinces, first, a database of daily precipitation matrices for the statistical period of 1990-2020 related to 25 rain gauge and synoptic stations of the province was formed.
Precipitation data were fitted using the Goodness of fit test to determine the degree of difference between the observed and expected data. The Markov chain second-order experimental distribution algorithm was used for the continuity and return time of the over time. by used and the help of programming and coding in MATLAB and R software, is calculated on a seasonal and monthly scale with a threshold of 5 mm to be the basis for extracting and zoning dry Spells in ArcGIS software.. The results showed that the occurrence of a rainy day after another rainy day (n11), in the humid eastern regions with a 21% probability of having a low incidence rate. In contrast, in the arid regions of the province (center and south), the frequency and percentage of occurrence of one dry spells following another dry period, function (n00) with 2159 days and 80% probability of occurrence are more probable. Finally, the prediction of climate change with the attitude of evaluating dry periods with the HADGEM2-ES model algorithm related to the fifth report of the Intergovernmental Panel on Climate Change (IPCC-IR5) in the mid-decade showed that wetlands such as Yasuj, Sisakht and Kakan are risky areas. Climate fluctuations are, on average, 15 to 18 percent drier.