جستجوی مقالات مرتبط با کلیدواژه « آزمون سن » در نشریات گروه « آب و خاک »

Climate change causes changes in temperature and rainfall and consequently affects river discharge. Changes in rainfall can be simulated by global circulation models under different climatic scenarios but investigations of changes in river discharge require rainfall-runoff models. The Galikesh basin as one of most flood-prone basins in Gloestan Province is considered for determination of changes in river discharge under climate change effect. Temperature and rainfall is produced for future climatic period (2011-2030) based on global circulation model HADCM3, using LARS-WG data generator model. The produced data under different climatic scenario are used as inputs of calibrated IHACRES model to simulate river discharge for future climatic periods. The climate change analysis shows that under different scenarios in the study area air temperature in different months increases, but the annual precipitation decreases. The Mann-Kendall test is used to detect monotonic trend of seasonal and semiannual river discharge series. The results show no trend for spring and first half of the year and a negative trend for other seasons and second half series in 5 percent significance level.

In this study, trends of precipitation of the NW of Iran were examined in monthly, seasonal and annual time scales using the Mann-Kendall method, which is developed in three different variations namely MK1, MK2 and MK3. Data used here were the information of precipitation for 16 selected stations in the period of 1955-2004. The Sen's slope estimator was used for detecting the slope of precipitation trend line. Results showed that there are downward trend in the most of stations for the NW of Iran's precipitation (except the Astara, Rasht and Mahabad stations) in annual time scale. The most strong positive trend slope in the case of annual precipitation belonged to the Astara station, which was equal to 6.42 mm/yr, however, the most strong negative trend slope belonged to the Anzali station, which was equal to -6.18 mm/yr. In monthly time scale, the numbers of months having negative trends were greater than that of the positive ones. All stations were experienced both negative and positive trends except the Jolfa, in which all months experienced negative trends for monthly precipitation data.