邻近绿洲的荒漠表层土壤逆湿和对水分"呼吸"过程的分析  

Analysis of Inverse Humidity and Moisture Respiration Process of Surface Soil in Desert Near Oasis

作　　者：张强[1] 卫国安[2] 

机构地区：[1]中国气象局兰州干旱气象研究所,甘肃兰州730020 [2]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《中国沙漠》2003年第4期379-384,共6页Journal of Desert Research

基　　金：国家自然科学基金项目(批准号:40175004);国家重点基础研究发展规划项目"我国重大气候灾害形成机理和预测理论的研究"(编号G1998040904 2);中国科学院知识创新领域前沿项目(编号210039)共同资助

摘　　要：利用"我国西北干旱区陆气相互作用试验"2000年8～9月在甘肃敦煌进行的野外观测资料,分析了临近绿洲的荒漠戈壁土壤湿度和大气湿度特征,发现:活动层内土壤空气湿度远离饱和状态,水分以气态和液态两种形态存在和输送;由于绿洲效应影响,临近绿洲的荒漠戈壁不仅近地层空气多为逆湿,而且这种空气逆湿在夜间较强时可以继续向土壤活动层延伸。土壤湿度日变化能清楚地被区分为湿维持(1～6时)、水分损失(7～11时)、干维持(12～18时)和水分补充(19～0时)等4个阶段,其中湿维持阶段的土壤逆湿是最主要的结构特征,这一土壤湿度结构表明夜间土壤可以通过凝结吸收大气水分,它与白天的土壤水分蒸发共同构成土壤对大气水分的"呼吸"过程;活动层土壤逆湿的形成与土壤温度状态、大气逆湿强度和大气稳定度都有关。In this paper, by utilizing the data of the observation (AugustSeptember 2000) of Dunhuang, which was observed in Landatmosphere Interactive Field Experiment over Arid Region of Northwest China , the characteristics of the soil moisture, atmosphere humidity are analyzed. It is found that air humidity in the active soil layer is far from saturated state, and the soil moisture exists and transfers as gaseous state and liquid state separately. Because of influence of oasis, over desert or Gobi near the oasis, atmospheric humidity not only often appears inverse gradient in surface layer, but also the inverse humidity can extend to soil surface at night. Daily variation of soil moisture can be clearly divided into 4 stages: wet stage (at 1:00～6:00), moisture loss stage (at 7:00～11:00), dry stage (at 12:00～18:00) and moisture takeup stage (at 19:00～0:00). It is shown that surface soil has inverse wetness at late night, and can absorb moisture from the air through condensation in night. This process and soil moisture evaporation process in daytime combine into a respiration process of soil moisture. And the formation of inverse humidity of surface soil is relative to the state of surface temperature, intensity of inverse humidity of atmosphere and atmospheric stability.

关 键 词：荒漠 土壤湿度 大气湿度 土壤逆湿 绿洲效应 土壤水分 野外观测 

分 类 号：S152.7[农业科学—土壤学] S151.91[农业科学—农业基础科学]