Investigation of Temperature and Rainfall Parameters of Haraz River Basin affected by Climate Change

Due to the low spatial resolution and simplification of atmosphere general circulation models compared to regional and short-term models, the outputs of these models cannot represent an accurate approximation of climatic conditions of the study area. Due to time-consuming and lack of economic efficiency in the use of dynamic models, there has been increased public attention to the use of statistical downscaling methods. One of the most useful and common methods in statistical downscaling is SDSM. For this purpose, the first, the atmospheric parameters in the region over the past 32 years (1984-2015) was investigated by the Mann-Kendall test. The results showed that changes in temperature and rainfall data have a significant trend. Then, by down-scaling, the data using SDSM software, the daily parameters of maximum, minimum, average temperature and rainfall of Haraz river basin in Mazandaran province were simulated according to RCP2.6 (optimistic) and RCP8.5 (pessimistic) scenarios and CanESM2 Climatic Model from the new CMIP5 series in three periods of twenty years from 2020 to 2079. Finally, under the RCP8.5 critical scenario, until the end of the prediction period, the maximum, minimum and average temperature of the basin will be increased 0.91, 1.13 and 0.96o C, respectively and precipitation decreased 15.1% (7.4 mm) compared to the base period.