Impact of Extreme Climate Events on Terrestrial Water Storage from GRACE over China

Abstract:

Assessing the impacts of climate change on water resources is a vital issue for China and the rest of the world. In this study, we analyze the connections between the GRACE-based terrestrial water storage anomalies (TWSAs) over China and two climate indices linked to equatorial Pacific and Indian oceans sea surface temperatures (SSTs) during January 2003 and June 2014. Results indicate that the regions of the Yun-Gui Plateau, the Northeast Plain, the Qaidam Basin and a small portion of the North Plain are mainly influenced by Pacific SSTs, especially during the ENSO events. In particular, an extremely wet season over Yun-Gui Plateau and a very dry condition in the north part of the Northeast Plain in 2008-2009 observed by GRACE are clearly connected to the La Niña event. High (low) TWS in the mid-latitude regions of China range from 29-33°N and 99-120°E are correlated with the negative (positive) IOD phases between September 2006 and April 2011. The TWSAs in Sichuan Basin is persistently affected by IOD index and the severe drought in late 2006 is significantly correlated to the strong positive IOD event. After August 2010, results show significant positive correlation between the TWSAs and IOD over the Qaidam Basin and central Tibet Plateau regions. In addition, the relations between TWSAs and ENSO/IOD are mostly impacted by east-west mountain ranges, as strong correlations generally occur on the upwind side of mountain ranges and weak correlations on the leeward side. The Qingling Mountains are the boundary (~33°N) of the impact of IOD on water storage variations between the North and the South of China.