联合GRACE和气象水文数据研究2010～2016年亚马孙平原水储量异常变化与极端气候和ENSO的关系

Correlation between ENSO and Total Water Storage Change Anomaly with Extreme Weather Events over Amazon Basin from 2010 to 2016 Estimated from GRACE and Hydroclimatic Data

利用GRACE时变重力场模型反演2009-07～2017-06期间亚马孙平原的水储量变化,在移除趋势和季节性周期信号后,计算得到其与ENSO指数之间具有较强的相关关系和一定的时延性,并从季节层面进行分析得到ENSO对亚马孙平原旱、雨两季的不同影响,表现为旱季受到ENSO显著影响而雨季受到的影响则较小。最后,结合水文数据分析指出,ENSO会通过影响降雨量进而影响相应区域的水储量变化,且该现象在流域内两次极端旱灾中有较为突出的表现。

Extreme weather events in the Amazon basin,which have occurred frequently in recent years,are generally considered to be associated with the abnormal change of rainfall,due to their strong correlation with each other.The occurrence of the El Nino/southern oscillation(ENSO)events are important factors leading to abnormal changes in rainfall.Because several extreme weather events since 2010 happened just after ENSO,it is very important to understand the impact of ENSO on the Amazon basin.Using GRACE gravity field solutions,the total water storage change(TWSC)in Amazon basin from July 2009 to April 2017 is estimated.The correlation between TWSC and ENSO index are proved to be strong with a certain time lag when trend and seasonal signals are removed.Then the different effects of ENSO on Amazon basin during dry and rainy seasons are analyzed.The results show that the dry season is significantly affected by ENSO while the rainy season is less affected.Finally,the results show that ENSO can affect TWSC in certain area by influencing the rainfall is found when combined with the hydroclimatic data analysis.This phenomenon is more prominent in the two extreme droughts in Amazon basin.