灾害学2016，Vol.31Issue(4)：95-102,8.DOI:10.3969/j.issn.1000-811X.2016.04.017
亚洲季风区过去700年来夏季极端干／湿事件多尺度变化特征分析
Multi-scale Analysis of the Extreme Dry/Wet Events in Asian Monsoon Region in Summer During Last 7 Centuries
摘要
Abstract
Monsoon failures,mega droughts,and extreme flooding events have repeatedly affected the agrari-an peoples of Asia over the past millennium.A scarcity of long-term instrumental climate data for many remote re-gions of Monsoon Asia impedes progress toward resolving these issues.To better elucidate the spatial complexity of the Asian monsoon,a large-scale,spatially explicit,long-term data set is needed.This context is provided here by our Monsoon Asia Drought Atlas (MADA).The MADA provides a seasonal-to centennial-scale window into the A-sian monsoon’s repeated tendency for extended dry and wet extremes with distinct spatial flavors of response.Re-cently,ensemble empirical mode decomposition (EEMD)method is developed for non-linear and non-stationary signal analysis.The EEMD method is instituted and utilized in several fields such as de-noising,ocean surface measurement,metrology,image processing and so on.The method can work on nature signals (non-linear and nonstationary signals)as well as reducing the speckle noise.The EEMD method is like as a filter bank that the sig-nal is decomposed into several intrinsic mode functions(IMFs)and the frequencies of IMFs are arranged in decrease order (high to low)after the EEMD processing.The scaling mode of the EEMD method is similar to wavelet trans-form,but the signal resolution at different frequency domain is not decrease by down-sampling.In this paper,we propose the EEMD method to extract the multi-scale characters of the variability of extreme dry/wet events in Asian monsoon area.Using the Palmer Drought Severity Index data of MADA from 504 stations in Asian monsoon area in summer from 1300-2005a and EEMD method,we get the series of the number of grids which is especially and seri-ous wet or dry in this region by an interval of 5 years,and analysis the variations of these series.Based the feature of nonlinear/nonstationarity and multi-scale in climatic system,applying EEMD to the series of the number of grids which is especially and serious wet or dry for the purpose of multi-scale analysis,different scale signals(IMFs) have been separated,and give the variance contributes and do the test of significant for each IMF.By analyzing the variations of IMFs,hereby,the changes in different scales for the extreme dry/wet events in Asian monsoon region in summer during last 7 centuries have been uncovered,and get the effect of different IMFs on the changes of dry-wet in Asian monsoon region.关键词
亚洲季风区/极端干/湿事件/气候变化/集合经验模态分解Key words
Asian monsoon region/extreme dry/wet events/Ensemble empirical mode decomposition分类
天文与地球科学引用本文复制引用
杨萍,侯威,颜鹏程..亚洲季风区过去700年来夏季极端干／湿事件多尺度变化特征分析[J].灾害学,2016,31(4):95-102,8.基金项目
国家自然科学基金（41675092；41375069；41505061）；公益性行业科研重大专项 （）
