干旱荒漠区沙土凝结水与微气象因子关系

凝结水作为干旱区降雨以外的主要水分补给,具有重要的生态水文意义。目前,凝结水研究已成为干旱区生态水文学研究的一个重要组分.通过定位观测,对凝结水的形成机理、形成量和影响因子已有了初步的认识.但是受土壤水分、风速和下垫面性质的影响,凝结水量与微气象因子的关系复杂,导致凝结水模拟估算存在诸多困难。本文通过控制试验,在排除土壤水分、风速和下垫面对凝结水形成过程影响的条件下,开展观测,建立凝结水形成速率与近地层微气象因子之间的多元回归方程,旨在为凝结水模型构建提供参考。结果显示:凝结水形成速率与空气相对湿度呈波尔兹曼函数关系,与气温和地表温度均呈显著的线性负相关关系,而与气温和地表温度差、露点温度呈显著的线性正相关关系。多元回归分析显示,沙土凝结水主要受近地层空气相对湿度、气温和地表温度的控制,表明在凝结水模型构建中应重点考虑这3个微气象因子的影响。

An Experimental Observation of the Relationship between Sandy Soil Condensation Water and Micrometeorological Factors in the Arid Desert Region

As one of the main water sources besides rainfall in arid areas, condensation water has some important eco-hydrological function. At present, condensation water has become an important component of eco-hydrological research in arid areas, and its formation mechanism, quantity and impact factors have been preliminarily understood based on some long-term station observations. However, the complicated relationship between condensation water and micrometeorological factors caused by the influence of soil moisture content,wind speed and underlying surfaces makes it very difficult to simulate and estimate condensation water. In this study, based on control experiments, in which the influence of soil moisture, wind speed and underlying surface was excluded, multivariate regression equations between formation rate of condensation water and surface micrometeorological factors were set up. The aim of the paper is to provide important parameters for condensation water modelling on. The results showed that a Boltzmann function relation existed between formation rate of condensation water and relative air humidity; the rate of condensation exhibited significant linear negative correlation with the air temperature and surface temperature, while exhibited significant linear positive correlation with dew point temperature and difference between air temperature and surface temperature. Multiple regression analysis showed that formation process of condensation water was mainly controlled by surface relative air humidity, air temperature and surface temperature, which indicated the three micrometeorological factors should be considered seriously in condensation water modeling.