中国小流域径流对气候变化的敏感性分析

Sensitivity of Runoff to Climate Change in Small Drainage Basins in China

全球变暖导致的水文水资源问题越来越突出。为了预测气候变化对径流水资源的影响,该文利用全国469个小流域20多年年平均降水量、年平均气温和年平均径流量数据,细分不同的气候情景,分析径流变化对气候变化的响应程度。结果表明:一般来说,径流与降水变化趋势一致,与气温变化趋势相反,但是在局部地区由于温度的升高增加的降水超过蒸发的影响,径流随着气温升高反而增加;干旱地区径流对气温比对降水的响应更加显著,而在湿润地区径流对降水比对气温的响应更加显著;其中年平均气温11℃～15℃、年降水量400mm～800mm的华北地区,年均径流深对年均降水量的响应最敏感,而年平均气温低于5℃、年降水量低于400mm的内蒙古高原西部及新疆北部的天山和阿尔泰山迎风坡低山地带,年均径流深对降水的响应最小;年均降水量200mm～400mm、年平均气温6℃～10℃的内蒙古高原东部,气温对径流的影响最明显,而年平均气温16℃～25℃,年平均降水量800mm～1600mm的长江中下游地区、西南的大部分地区以及华东华南的大部分地区,径流对气温的响应相对不显著。

Global warming, which has frequently attracted the attention of the society, will possibly change the current regimes of precipitation, hydrological cycle and water resources. In this article, the effects of climate change on runoff were analyzed with data from 469 small drainage basins for 20 years in China. First, we divided the drainage basins into different groups according to the mean annual temperature and mean annual precipitation under which they are situated. Then we assume an increase of 0℃,1℃ and 2℃ in mean annual temperature and a change of 20%,10% and 0% in mean annual precipitation. So that 15 climate-change scenarios were constructed by integrating each temperature change with each precipitation change. The general structure of a nonlinear model on climate factors and runoff relationship was established with multi-variable method. The response of runoff to climate variations was estimated with the statistical model under the 15 climate-change scenarios.The results show: Runoff will generally increase with precipitation increase and decrease with temperature increase, but still in some special areas runoff has a positive correlation with temperature, which is due to the 'positive' effect of more precipitation associated with higher temperature dominate the 'negative' one of evaporation on runoff; In arid region, runoff is more sensitive to temperature change than precipitation change, while in humid region runoff is more sensitive to precipitation change than temperature change; Therein runoff in the North China Region, which has mean annual temperature between 11℃～15℃ and precipitation between 400 mm～800 mm,is most sensitive to precipitation change among all regions in China, while in the western Inner Mongolian Plateau, the Tianshan Mountain, and the low windward slope of Altai Mountain where have mean annual temperature below 5℃ and precipitation less than 400 mm, the runoff is least sensitive to precipitation change; Runoff in the eastern Inner Mongolian Plateau, which has mean annual temperature between 6℃～10℃ and precipitation between 200 mm -400 mm,is most sensitive to temperature change, while it is least sensitive where have mean annual temperature between 16℃～25℃ and precipitation between 800 mm ～(1 600 mm,) as the middle and lower Yangtze River area and most parts of the southwest China, east China and south China.