title: Analysis of Precipitation Characteristics during 1957-2012 in the Semi-Arid Loess Plateau, China.
abstract: Precipitation is the only water supply and most important factor affecting vegetation growth on the slopes of semi-arid Loess Plateau of China. Based on precipitation data from 7 synoptic stations in the study area over the period 1957-2012, the trends of precipitation and standardized precipitation index (SPI) were analyzed by using linear regression, Mann-Kendall, and Spearman's Rho tests at the 5% significance level. The results show that (1) the precipitation fluctuation of monthly precipitation was intense (coefficients of variation> 100%), and the drier years were recorded as 1965 and 1995 at all stations. (2) The significant change trend of different stations varied on different time scales: the Changwu station had a significant decreasing trend in April (-0.488 mm/year) and November (-0.249 mm/year), while Luochuan station was in April (-0.457 mm/year); Changwu station displayed a significant increasing trends in winter (0.220 mm/year) and a significant decreasing trends in spring (-0.770 mm/year). The significant decreasing trends in annual precipitation were detected at the Suide (-2.034 mm/year) and Yan'an (-2.129 mm/year) stations. (3) The SPI-12 series analysis suggests that the drought degree of Yulin and Changwu was the lowest and that of Hengshan was the highest among the 7 synoptic stations.
authors.affiliation: Key Laboratory of tourism and resources environment in colleges and universities of Shandong Province, Taishan University, Taian, Shandong, China; Beijing Forestry University, Forestry Ecological Engineering Research Center, Ministry of Education, Beijing, China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Zhao
authors.affiliation: College of Resources and Environment, Shandong Agricultural University, Taian, China.
authors.forename: Xinyang
authors.initials: X
authors.lastname: Yu
authors.affiliation: Beijing Forestry University, Forestry Ecological Engineering Research Center, Ministry of Education, Beijing, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Ma
authors.affiliation: Beijing Forestry University, Forestry Ecological Engineering Research Center, Ministry of Education, Beijing, China.
authors.forename: Qingke
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Beijing Forestry University, Forestry Ecological Engineering Research Center, Ministry of Education, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Sedimentation, China Institute of Water Resources and Hydropower Research, Beijing, 100044, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
authors.affiliation: Beijing Forestry University, Forestry Ecological Engineering Research Center, Ministry of Education, Beijing, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Ai
authors.affiliation: Beijing Forestry University, Forestry Ecological Engineering Research Center, Ministry of Education, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002681:China; D011891:Rain