报告题目：华北和西南澳大利亚的孪生干旱 

报告时间：2014年10月10日(星期五) 10:00-11:30 

报告地点：尚贤楼1楼108报告厅 

报告主持人: 曹春正 

欢迎广大师生踊跃参加！ 

专家简介： 

Yun Li, (Commonwealth Scientific and Industrial Research Organization, Australia), is a principal statistical scientist with an interest in the problems posed by geophysical and climate data sets. He received a Ph.D. in statistics from The University of Western Australia in 1998. His current interests include the application of the statistical theory of extreme values to climate change, nonlinear modeling and statistical downscaling models. 

Abstract 

Rainfall in both southwest Western Australia (SWWA) and North China (NC) has been declining substantially since the mid-1960s, which leads to a series of twin droughts in both regions since then. Using observed rainfall datasets in China and Australia and the NCEP reanalysis dataset during 1951-2008, we show that the decline of SWWA rainfall is in early austral winter (MJJ, May-June-July) while the reduction of NC rainfall is in late boreal summer (JAS, July-August-September). We then examine the relationship between SWWA MJJ rainfall and NC JAS rainfall during 1951-2008, and find that a significant link exists between these two rainfall series with a correlation of 0.43 and this link remains after the data are detrended. In particular, this relationship accounts for up to 62% variance on interdecadal timescales, and seems to be driven by the poleward shift of the Southern Subtropical High Ridge (SSHR) and the Northern Subtropical High Ridge (NSHR) over longitudes (110°-150°E). The poleward shift of the SSHR may induce to an anomalous anti-cyclone centered near the south Australian coast resulting in anomalous easterlies of dry air to SWWA, while the poleward shift of the NSHR is associated with an anomalous anti-cyclone in East Asia near NC causing anomalous northeastlies of dry air to NC. The pole-ward shift of SSHR/NSHR may be linked to the warming sea surface temperatures (SSTs) in the tropical Indian-western Pacific. Our results suggest that the poleward shifts of the SSHR and the NSHR instigated by the warming SSTs in the tropical Indian-western Pacific may have partially attributed to the rainfall reduction in both regions. 

This work was supported by the Australia-China Bilateral Climate Change Partnership through the Australian Department of Climate Change and Energy Efficiency and the Indian Ocean Climate Initiative Stage 3, and Climate Adaptation Flagship. 

Reference 

Li, Y., J. Li, and J. Feng, 2012: A teleconnection between the reduction of rainfall in southwest Western Australia and North China. Journal of Climate 25, 8444–8461. 

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