THE GRACE SATELLITES DETECT RECENT EXTREME CLIMATE EVENTS IN CHINA

摘要

As the climate changes, the extreme climates are occurring more frequently over the globe. In China,drought or flood strikes almost every year recently and there have been several disastrous events inthese years. We show that some of the disastrous events are so strong that corresponding gravity changecan be observed by geodetic satellites. The Gravity Recovery and Climate Experiment (GRACE),which is a joint mission between NASA and DLR, is used to obtain the temporal gravity field overChina. One primary job of GRACE is to map Earth time-variable gravity field with temporal resolutionof 2-4 weeks and spatial resolution of 300km-400km. Over the years the twin satellites have observedthe loss of mass in Antarctic and Greenland, strong earthquakes, severe climate change in SouthAmerica and so on, which provides a unique way to study the geophysical or climatological process. Inthis report, the Level-2 product from the Center for Space Research is used and we focus on specificareas including the Yangtze River downstream area and the southern provinces of China, wheredrought and flood are often in these years. It is shown that with decorrelation, filter and other processes,the gravity anomalies observed by GRACE match the extreme climate events and the hydrological datafrom the Global Land Data Assimilation System (GLDAS).