1961-2010 年中国降水强度变化趋势及其对降水量影响分析

探讨区域降水强度的时空变化趋势对于揭示区域气候变化规律、有效应对气候变化水资源影响等具有重要意义。利用756 个气象观测站1961-2010 年50 年逐日降水资料，分析了中国不同等级降水（小雨、中雨、大雨、暴雨及年均降水）强度的年际、年代际的变化趋势，以及不同等级降水变化在降水量增量中的贡献。结果表明：在年际变化中，降水强度总体呈现上升趋势，显著上升区域主要分布在中国东部秦岭-淮河线以南的地区；在不同等级降水强度中小雨强度变化趋势最为显著，中雨以上级别降水强度则相对稳定。在年代际变化中，各区域年代际降水强度变化差异明显，20 世纪60 年代和70 年代下降显著，80 年代、90 年代、21 世纪的前10 年则上升明显。此外，降水强度对降水量增量贡献由东至西呈“大-小-大-小”的相间带状分布；在中国西部，小雨、中雨、大雨强度对降水量增量起主导作用，而在中国东部暴雨降水强度在降水量贡献中起主导作用，且在东北区东南、黄淮海西北以及西南中部作用更加明显。

Research of trend variability of precipitation intensity and their contribution to precipitation in China from 1961 to 2010

Precipitation intensity is one of important meteorological factors determining occurrence of extreme hydro events and variation of available water resources. China is a country with frequent floods/droughts and unbalanced demand/supply of water resources. To reveal the climate change rhythms and deal with water resources issues, it is valuable to research the temporal and spatial variations of precipitation intensity. Using the daily precipitation measurements during 1961-2010 from 756 stations across China, we researched the inter-annual and inter-decadal variations of precipitation intensity for the light, moderate, heavy and storm rainfall, respectively, and quantified their impacts on total precipitation. The overall trend of variations of precipitation intensity is positive. Such a positive trend was mainly observed in the region south of Qinling Mountains and the Huaihe River. Among the four grades of rainfall, the light rainfall intensity has the strongest positive trend; whereas, the moderate, heavy and storm rainfalls have no significant trends. The precipitation intensity also had obvious inter-decadal variations. At decadal scale, the precipitation intensity was weak in the 1960s and 1970s while it was strong since the 1980s. The contribution of precipitation intensity variations to total precipitation spatially occurred in the order of‘large-small-large-small'from east to west. The storm rainfall plays a dominant role in the variations of total precipitation in the eastern China, particularly in the southeast of Northeast China, west of North China and middle of Southwest China. The light, moderate and heavy rainfalls play a dominant role in the variations of total precipitation in the western China.