Spatiotemporal analysis of nonlinear trends in precipitation over Germany during 1951-2013 from multiple observation-based gridded products
Spatiotemporal analysis of nonlinear trends in precipitation over Germany during 1951-2013 from multiple observation-based gridded products
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基于多个基于观测的网格产品对 1951-2013 年德国降水非线性趋势的时空分析
DOI：
10.1002/joc.5939
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Wei Meng
中科院分区：
文献类型：
--
作者：
Duan Zheng;Chen Qiuwen;Chen Cheng;Liu Junzhi;Gao Hongkai;Song Xianfeng;Wei Meng
利用集合经验模式分解(EEMD)方法，分析了1951-2013年德国年降水量和季节降水量趋势的时空分布特征。使用和比较了三种广泛使用和公认的基于高分辨率观测的网格降水产品，即气候研究单位(CRU)时间序列数据、全球降水气候学中心(GPCC)全数据再分析数据和欧盟-FP6项目集合派生数据集(EOBS)。不同产品之间的比较表明，CRU在构建德国上空的网格化产品时使用的计量站数量相当少(最多36个)，在其他应用中应非常谨慎，而且CRU总体上降水量较少，年际变率较小；GPCC和EOBS在季节和年降水量的时空分布以及所确定的趋势上非常一致。对趋势的时空分析表明，在大多数情况下，1951-2013年期间的降水量趋势是高度非线性的，并随时间变化。特别是春、夏、秋三季降水变化趋势差异较大。因此，以前研究所基于的线性趋势假设是无效的。德国66%以上的地区(特别是德国北部和东部)的年降水量呈增加趋势，而且增加趋势的幅度通常随着时间的推移而增强，例如GPCC显示，增加趋势的平均幅度从1951-1980年期间的6.3%上升到1951-2013年期间的12%。德国各地季节降水总量的趋势在空间和时间上都有相当大的变化。这项研究是首批应用EEMD方法全面分析德国降水量随时间变化趋势的研究之一，有望提高我们对复杂而非线性的区域气候系统的理解。
Spatial and temporal patterns of trends in annual and seasonal precipitation over Germany during 1951–2013 were analysed using the ensemble empirical mode decomposition (EEMD) method. Three widely used and recognized high‐resolution observation‐based gridded precipitation products, the Climatic Research Unit (CRU) time‐series data, Global Precipitation Climatology Centre (GPCC) Full Data Reanalysis data and the EU‐FP6 project ENSEMBLES derived data set (EOBS), were used and compared. Comparison among different products showed that the CRU used a considerably lower number of gauge stations (maximum 36) in the construction of gridded product over Germany and should be used with great caution for other applications, and overall CRU presented less precipitation and smaller inter‐annual variability; GPCC and EOBS agreed well in the spatial and temporal distribution of seasonal and annual precipitation, as well as the identified trends. The spatiotemporal analysis of trends showed that trends in precipitation during 1951–2013 were, in most cases, highly nonlinear and varying over time. In particular, the spring, summer and autumn precipitation showed large variations in trends. Therefore, the assumption of linear trends on which previous studies were based is invalid. Annual precipitation showed increasing trends in over 66% of Germany (particularly northern and eastern Germany), and the magnitude of increasing trends were generally enhanced over time, e.g. GPCC showed that the average magnitude of increasing trends rose from 6.3% for the 1951–1980 period to 12% for the 1951–2013 period. There were considerable spatial and temporal variabilities in trends in seasonal precipitation totals over Germany. This study is among one of the first studies applying the EEMD method to a comprehensive analysis of time‐varying trends in precipitation over Germany, which is expected to improve our understanding of the complex and nonlinear regional climate system.