秦岭南北地区环境变化响应比较研究

利用气象水文部门截止1999年的气象水文实测数据,计算分析在气候变暖过程中中国秦岭具有的区域响应分界意义。由于气候变暖,在百年时间尺度上,通过旱涝指数分析证明秦岭以北进入干旱期,秦岭以南为湿润期;在10年时间尺度上,陕南气温变化较小,而关中气温增高较快,陕南与关中年均气温差值变小;关中和陕南降水量差值变小,二者同时干旱或陕南更干旱,反映出秦岭在气候变化中显著的分界作用。气候变暖,渭河与汉江年径流系数同步减小,其中渭河径流系数由50年代的02下降为90年代的01以下,渭河流域已变为少水带,即相当于气候上的干旱区。秦岭以北地区较其以南地区环境干暖化的趋势更明显,这对于认识全球变化的区域响应差异有参考意义。

A comparative study on environmental change response over the northern and the southern regions of the Qinling Mountains

Based on the data up to 1999 from the hydro-climatological departments, this paper analyzes the climatic dividing implications of Qinling Mountains in regional response to the process of global warming, due to which the Grades of Dryness/wetness (GDW) in 100-year scale show that the northern region has entered an arid period, and the southern, a humid period. At decade scale, the D-value of annual average air temperature over Southern Shaanxi (Hanjiang Valley) and Central Shaanxi Plain (Guanzhong Plain) has narrowed, i.e. the former with slight change and the latter with rapid increase in temperature. Both regions are arid with decease in precipitation D-value, namely, the plain becomes warmer while the south drier. Qinling Mountains play a predominant role in the climatic dividing. The runoff coefficient (RC) of Weihe River decreases synchronously with that of Hanjiang River due to climate warming . The RC of Weihe dropped from 0.2 in the 1950s to less then 0.1 in the 1990s.Weihe valley (Guanzhong Plain) is practically an arid area as a result of the shortage of water .The successive 0.5 and 1.0℃ temperature anomaly over China marks, perhaps, the important transition period in which the environment becomes more vulnerable than before .The study shows the obvious trend of environmental aridity, which is of help to the understanding of regional response to the global climate change.