Abstract:

In order to further study the influence of various climate changes and hydrological factor on arid changes in Haihe River basin, we analyze temperature, precipitation and runoff of Haihe River basin by Mann-Kendall nonparametric tests. We also analyze the drying characteristics by the method of Z index .The results show that the drought of Haihe River basin has changed from wet to normal to dry since the 1950 s. At the beginning of the 21 st century, the northern basin became a little drought. Mostly, the area coverage is lower than 40%, but there were also some drought that covered more than 98% of the area. From the time, the 1980 was a watershed in droughts occurrence. In terms of both the frequency and on the average coverage, it was more dry after 1980 than before. From the drought occurrence frequency, mild and general drought of Haihe River basin in high frequency distributed in the Luanhe River basin as well as the northern mountains, and in central plains region the drought frequency is relatively low. Major drought event occurred more frequently in central and southern plains region. Overall, the drought occour frequence in Luanhe River basin is the highest ,and the eastern region of Haihe River basin is much lower, and the western region is relatively low frequency.

Key words: climate change, aridification, Mann-Kendall nonparametric tests, method of Z index, Haihe River basin