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利用2005和2006年黄土高原陆气相互作用观测资料分析了不同下垫面的土壤湿度状况,并从土壤物理学的角度分析了造成各种下垫面湿度分布和变化不同的原因,得到如下结论:在近地层,各站的土壤湿度具有微弱的日变化特征;5cm层土壤含水量对降水比较敏感,随着降水的发生,土壤含水量迅速上升。随着深度的增大,土壤含水量上升的幅度逐渐减小,且滞后时间逐渐延长,但到了40cm深度处,土壤含水量就基本不受降水的影响了。从全年来说,该地区一年中可以区分出两个主要的水分时期,即蓄水期和失水期。蓄水期处于雨季,从6月到9月,10月开始到次年5月为失水期。冬春季节是土壤含水量最少的季节,从1月下旬一直持续到3月上旬,9月是土壤含水量最大的季节。土壤含水量变化规律可以分为两层,在25cm深度以上,冬春季节从上层到下层依次减小,夏秋季节从上到下依次增大;25cm到40cm土层全年都是从上层到下层依次增大;20cm土层附近相对于其余各层土壤含水量在全年都是最低的。
Based on the observation data of the interaction between the land and the atmosphere on the Loess Plateau in 2005 and 2006, the soil moisture conditions of different underlying surfaces were analyzed. The causes of the different humidity distributions and changes of various underlying surfaces were analyzed from the perspective of soil physics. The following conclusions were obtained : In the near-surface layer, the soil moisture at each station has a weak diurnal variation. Soil moisture in the 5 cm layer is sensitive to precipitation. With the occurrence of precipitation, the soil moisture content increases rapidly. With the increase of depth, the increase of soil water content decreased gradually, and the lag time gradually extended, but at the depth of 40 cm, the soil water content was basically unaffected by precipitation. Throughout the year, the region can distinguish between two major water phases during the year, namely the water-storage period and the water-loss period. Impoundment in the rainy season, from June to September, October began in May next year as the loss of water. Winter and spring are the seasons with the least soil water content, which lasts from late January to early March. September is the season with the highest soil moisture content. The variation law of soil water content can be divided into two layers, above the depth of 25cm, the order of the spring and the spring decreases from the upper layer to the lower layer and increases from the upper layer to the lower layer in summer and autumn. The soil layer from 25cm to 40cm is from upper layer to lower layer Followed by the increase; 20cm soil layer relative to the rest of the soil moisture content in the lowest throughout the year.