عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The aim of this research is the study of trends in annual precipitation changes in some selected stations located in the Sefid Rood basin, applying the Man-Kendall non-parametric technique. The method is one of the most frequently used non-parametric techniques for trend analysis of precipitation on an annual scale. Six synoptic stations located in the Sefid Rood basin were selected for the analysis containing data records for a 30-year period (1978-2007). The results of the analysis indicated a significant trend in the precipitation of Khalkhal and Birjand stations, while there was no significant trend in Rasht and Zanjan stations with 95% and 99% confidence levels. At a 95% significance level, there was an ascending and significant trend in Lahijan station, whereas this trend was descending and significant in Mianeh station.