title: Analysis of the Nonlinear Trends and Non-Stationary Oscillations of Regional Precipitation in Xinjiang, Northwestern China, Using Ensemble Empirical Mode Decomposition.
abstract: Changes in precipitation could have crucial influences on the regional water resources in arid regions such as Xinjiang. It is necessary to understand the intrinsic multi-scale variations of precipitation in different parts of Xinjiang in the context of climate change. In this study, based on precipitation data from 53 meteorological stations in Xinjiang during 1960-2012, we investigated the intrinsic multi-scale characteristics of precipitation variability using an adaptive method named ensemble empirical mode decomposition (EEMD). Obvious non-linear upward trends in precipitation were found in the north, south, east and the entire Xinjiang. Changes in precipitation in Xinjiang exhibited significant inter-annual scale (quasi-2 and quasi-6 years) and inter-decadal scale (quasi-12 and quasi-23 years). Moreover, the 2-3-year quasi-periodic fluctuation was dominant in regional precipitation and the inter-annual variation had a considerable effect on the regional-scale precipitation variation in Xinjiang. We also found that there were distinctive spatial differences in variation trends and turning points of precipitation in Xinjiang. The results of this study indicated that compared to traditional decomposition methods, the EEMD method, without using any a priori determined basis functions, could effectively extract the reliable multi-scale fluctuations and reveal the intrinsic oscillation properties of climate elements.
authors.affiliation: College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266590, China. guobin07@mails.ucas.ac.cn.|State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science &amp; Technology, Shandong University of Science and Technology, Qingdao 266590, China. guobin07@mails.ucas.ac.cn.|State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China. guobin07@mails.ucas.ac.cn.|Key Laboratory of Surveying and Mapping Technology on Island and Reef, National Administration of Surveying, Mapping and Geoinfomation, Shandong University of Science and Technology, Qingdao 266590, China. guobin07@mails.ucas.ac.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China. zihan6688@126.com.|Key Laboratory of Geographic Information Science Ministry of Education, East China Normal University, Shanghai 200241, China. zihan6688@126.com.
authors.forename: Zhongsheng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266590, China. jinyunguo1@126.com.|State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science &amp; Technology, Shandong University of Science and Technology, Qingdao 266590, China. jinyunguo1@126.com.
authors.forename: Jinyun
authors.initials: J
authors.lastname: Guo
authors.affiliation: College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266590, China. luf3286@126.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266590, China. chencf@lreis.ac.cn.|State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and Ministry of Science &amp; Technology, Shandong University of Science and Technology, Qingdao 266590, China. chencf@lreis.ac.cn.
authors.forename: Chuanfa
authors.initials: C
authors.lastname: Chen
authors.affiliation: College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266590, China. liukangli111@sina.com.
authors.forename: Kangli
authors.initials: K
authors.lastname: Liu
mesh_terms: D002681:China; D057231:Climate Change; D036262:Empirical Research; D040362:Geographic Information Systems; D008962:Models, Theoretical; D011891:Rain; D012914:Snow; D014881:Water Supply
keywords: Xinjiang; ensemble empirical mode decomposition; intrinsic mode function; nonlinear characteristics; precipitation