title: Analysis of temporal and spatial trends of hydro-climatic variables in the Wei River Basin.
abstract: The Wei River is the largest tributary of the Yellow River in China. The relationship between runoff and precipitation in the Wei River Basin has been changed due to the changing climate and increasingly intensified human activities. In this paper, we determine abrupt changes in hydro-climatic variables and identify the main driving factors for the changes in the Wei River Basin. The nature of the changes is analysed based on data collected at twenty-one weather stations and five hydrological stations in the period of 1960-2010. The sequential Mann-Kendall test analysis is used to capture temporal trends and abrupt changes in the five sub-catchments of the Wei River Basin. A non-parametric trend test at the basin scale for annual data shows a decreasing trend of precipitation and runoff over the past fifty-one years. The temperature exhibits an increase trend in the entire period. The potential evaporation was calculated based on the Penman-Monteith equation, presenting an increasing trend of evaporation since 1990. The stations with a significant decreasing trend in annual runoff mainly are located in the west of the Wei River primarily interfered by human activities. Regression analysis indicates that human activity was possibly the main cause of the decline of runoff after 1970.
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China. Electronic address: zhaojing3942727@126.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Huang
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Jianxia
authors.initials: J
authors.lastname: Chang
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Liu
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Shengzhi
authors.initials: S
authors.lastname: Huang
authors.affiliation: State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Shi
mesh_terms: D002681:China; D057231:Climate Change; D003247:Conservation of Natural Resources / Q000379:methods / Q000706:statistics & numerical data / Q000639:trends*; D062070:Hydrology / Q000379:methods / Q000706:statistics & numerical data / Q000639:trends*; D012044:Regression Analysis; D045483:Rivers / Q000737:chemistry*; D062211:Spatio-Temporal Analysis; D058438:Water Cycle; D053833:Wetlands
keywords: Change points; Precipitation; The Mann–Kendall test method; The Wei River Basin; Trends