气候变化下汉江上游林地植被生态需水量的时空演变

研究气候变化下林地植被生态需水量的时空变化,对于保护涵养水源的林地植被系统,合理规划管理流域水资源有着重要作用。以汉江上游流域11个气象站点1971~2010年的气象资料为依据,采用结合1]土壤含水量与植物类型修正蒸散发量得到植被生态需水量的方式,从时空角度定量研究了在生长季4~10月份流域林地植被生态需水量及其趋势性变化,并且分析了生态需水量对各气象因子变化的敏感性程度。结果表明:汉江上游流域林地植被多年平均生长季生态需水量为6.915 8×109 m3,整体上呈现非显著性增加趋势,在空间分布上具有明显的地带性特征。生态需水量对不同气象因子有不同程度的敏感性:最高温度水汽压太阳辐射风速最低温度,生态需水量对各气象因子敏感程度的地带性分布特征还与各区域的纬度、海拔、植被类型和下垫面情况有关。

TEMPORAL AND SPATIAL VARIATION OF ECOLOGICAL WATER REQUIREMENT OF FORESTS IN THE UPPER REACHES OF THE HANJIANG BASIN UNDER CLIMATE CHANGE

The study of temporal and spatial variation of ecological water requirement of forests under climate change plays an important role in effectively protecting water conserving forest and vegetation system, rational planning and managing basin water resources.With thedata of 11 meteorological stations in the upper reaches of the Hanjiang Basin from 1971 to 2010, this paper quantitatively studied the temporal and spatial variation of ecological water requirementof forests in this basin and its trend in the growing season from April to October based on the methodthat the ecological water requirement is calculated with evapotranspiration corrected by combinating the soil moisture and plant types. The paper also analyzed the sensitivity degree of the ecological water requirement to the changes of meteorological factors. Results showed that the annual average ecological water requirementof forests in the growing season in the upper reaches of Hanjiang River Basin was 6.9158 × 10⁹m³ and it had aninsignificant increasing trend overall and a distinct zonal characteristics in spatial distribution. The order of sensitivity degree of ecological water requirement to meteorological factors, from the highest to lowest, was maximum temperature, vapor pressure, solar radiation, winds and lowest temperature respectively. Furthermore, the distribution characteristics of the sensitivity is influenced by the regional latitude, altitude,vegetation type and underlying surface.