中文摘要：

使用1948--2003年全球陆地和海洋的月降水资料，研究了热带地区年降水量场的趋势变化，同时还研究了ENSO事件与热带地区年降水量的关系。结果表明，在1948--2003年，热带地区年降水量场以负趋势为主要变化特征。给出了降水趋势明显的13个区域，指出热带海洋降水趋势明显的地区比陆地的范围广而且强度大，正趋势区基本都在南半球的海洋上，且北半球降水趋势明显的海洋区域都呈负趋势。研究结果还表明，ENSO事件可能是热带地区年降水量减少的一个重要原因；同时给出了ENSO事件发生时热带地区的明显旱涝区，并与以往的研究进行了比较。

英文摘要：

Using the monthly global land and ocean precipitation reconstruction data set during 1948m 2003, the trend variation of tropical annual precipitation fields and the relationship between the tropical annual precipitation and ENSO events have been investigated. Evidence suggests that a negative trend dominated the annual precipitation field. Thirteen regions with significant trend of precipitation are detected. Results show that the precipitation regions with a significant trend over the sea are wider than those over the land areas, and the positive trend regions mostly lie over the Southern Hemispheric Oceans, and the significant precipitation trends over the Northern Hemispheric Oceans are all negative. It is also shown that the ENSO events may serve as one of the significant causes for precipitation reduction in the tropics. Meanwhile, the drought and flood areas in ENSO event years are also identified and compared with the researches available.