集合经验模态分解下中国新疆降水变化趋势的区域特征  

Regional Features of Precipitation Variation Trends over Xinjiang in China by the Ensemble Empirical Mode Decomposition Method

作　　者：刘天虎[1] 刘天龙[2] 

机构地区：[1]新疆大学地质与矿业工程学院,新疆乌鲁木齐8300542 [2]新疆电力设计院,新疆乌鲁木齐830000

出　　处：《沙漠与绿洲气象》2015年第4期17-24,共8页Desert and Oasis Meteorology

基　　金：国家自然科学基金项目资助(41471030)

摘　　要：降水是中国西北干旱区水资源的重要组成部分,利用合理方法有效认识降水的区域变化规律对指导农业发展尤为重要。基于新疆16个国际交换站1961—2012年降水距平时间序列,利用集合经验模态分解(EEMD)方法,分析了新疆降水变化趋势的多尺度特征,并对其空间差异进行了初步探讨。近50多年来,新疆降水量整体上呈现出非线性的显著增多趋势,且其变化存在明显的年际尺度(3 a和6 a准周期)和年代际尺度(10 a和31 a准周期);各周期分量方差贡献率显示年际变化在新疆降水变化中占据主导地位,重构的降水年际变化趋势能精细刻画原始降水序列在研究时期内的波动状况;降水年代际变化揭示了新疆降水在1987年前后气候模态有了显著转换,由原来降水以负相位为主的气候模态转向正相位显著的气候模态;此外,降水变化趋势和转折时间均具有明显的区域差异。EEMD方法有助于加深人们对新疆降水多尺度变化特征的认识,是一种适用于非线性、非平稳信号分析的有效方法。Precipitation is the most key factor for water resources in the arid region of northwest China. Therefore, it is especially important for guiding agricultural development to understand the regional characteristics of precipitation with effective and reasonable methods. Based on precipitation anomaly time series from 16 international exchange stations in Xinjiang during the period from 1961 to 2012, the multi-scale characteristics of precipitation variability were analyzed using ensemble empirical mode decomposition （EEMD）method. Regional differences in variation trend and change-point were also preliminarily discussed. In the last more than 50 years, the overall precipitation in Xinjiang has exhibited a significant non-linear upward trend, and its changes have obviously presented an inter-annual scale （quasi-3 and quasi-6-year）and inter-decadal scale （quasi-10 and quasi-31-year）; The variance contribution rates of each components proved that the inter-annual change had a strong influence on the overall precipitation change in Xinjiang, and the reconstructed inter-annual variation trend could describe the fluctuation state of original precipitation anomaly during the study period. The reconstructed inter-decadal variability revealed that the climate mode in Xinjiang had a significant transformation before and after 1987, namely the precipitation anomaly shifting from a negative phase to a positive one. Furthermore, there were obviously regional differences in the non -linear changes and change-points of precipitation. At the same time, the results also suggested that the EEMD method can effectively reveal variations in long-term precipitation at different time scales and can be used for the complex diagnosis of non-linear and non-stationary signal changes.

关 键 词：新疆 降水距平 集合经验模态分解 本征模函数 区域差异 

分 类 号：P468[天文地球—大气科学及气象学]