Changes in tropical cyclone precipitation over China

Abstract

The Tropical Cyclone (TC) Precipitation (TCP) is partitioned from the station observations in China using the Objective Synoptic Analysis Technique (OSAT). The TCP spatial distribution, its ratio to total annual rainfall, the changes in the TCP volume, and the annual frequency of the torrential TCP events during the period 1957∼2004 are examined with a focus on their long-term trends in this study. Tropical cyclones significantly contribute to the annual rainfall in southern, southeastern, and eastern China, including Taiwan and Hainan islands. The TCP in most of the southeastern coastal regions can be more than 500 mm a year, accounting for 20∼40% of the total annual precipitation. Together with interdecadal and interannual variations, significant downward trends are found in the TCP volume, the annual frequency of torrential TCP events, and the contribution of TCP to the annual precipitation over the past 48 years. The downward trends were accompanied with the decreases in the numbers of TCs and typhoons that affected China during the period 1957-2004. These changes strongly suggest that China has experienced decreasing TC influence over the past 48 years, especially in terms of the TCP. Copyright 2006 by the American Geophysical Union.