陕南汉江谷地近40年气候变化及其生态环境意义

The Tendency of Climatic Change and It’s Effect on Ecosystem Environment in the Past40Years of Hanjiang Valley South ,Shaanxi

应用陕南汉江谷地17个测站1953～2000年气温、1961～2000年降水及1961～1999年区内汉江平均流量和最大流量实测记录,对气象数据和水文数据统计分析,结果表明,陕南汉江谷地近40 a来气温递增率为0.025℃/10 a,增温不明显,降水变化相对较大.其降水变化表现在3个方面:①年降水量减少,且趋势较强;②降水年内变化表现为夏增秋减趋势;③区内70%以上测站记录的暴雨频次和年暴雨总量变化表现为增加趋势.这种变化对陕南汉江谷地生态环境有一定负面影响,导致汉江河谷地区干旱化加强,两岸山区各种环境地质灾害频繁发生,水土流失呈发展趋势.

Based on the atmospheric temperature records from 1953 to 2000, precipitation records from 1961 to2000 and the flow of Hanjiang River records from1961 to 1999 of the hanjiang valley South of Shaanxi province.Analyzed the temperature, recipitation and surface flow records, the result indicates , the increasing progressively rate of temperature has been 0.025℃/10a in the past 40 years of the hanjiang valley South of Shaanxi province, it is not obvious to increase warmly, precipitation changes relatively big.Its precipitation change behaves in 3 aspects: Firstly, precipitation is diminution and the trend is marked; Secondly, precipita- tion is asymmetry in a year, which increase during the summer and reduces in the autumn.Thirdly, the number of times and precipitation of torrential rain amount change of more than 70% Monitoring station written down to stand show as trend of increasing. The change is negative influence on ecological environment of the hanjiang valley South of Shaanxi province, cause the hanjiang valley aridity is strengthen to take, two sides of mountain area many kinds of envi- ronmental disaster frequently occur, and the tendency of loss by run-off soil is more and more serious.