藏北高原土壤温湿变化特征分析

Variations of Soil Temperature and Soil Moisture in Northern Tibetan Plateau

利用"全球协调加强观测计划(CEOP)亚澳季风之青藏高原试验"(CAMP/Tibet,2001—2010)的观测资料,从不同的时间尺度分析了藏北高原不同地点不同深度的土壤温度和土壤湿度变化特征.结果表明:10 cm以上日平均土壤温度呈正弦变化,而10 cm以下土壤温度变化不大;各层土壤温度最高都出现在7～8月;年际气候的差异至少可以反映到40 cm土壤;各层土壤湿度无明显日变化,存在明显月变化,夏季降水量的多少对各层土壤湿度都有明显的影响.

Based on the soil temperature and soil moisture data obtained in GAME/Tibet （1996-2000） and CAMP/Tibet （2001-2010）, Variation features of soil temperature and soil moisture in different depths on different sites are analyzed. It is found that the variation of daily mean ground temperature above 10 cm has a one-year period. The variation can be showed as a sine curve. The yearly maximum temperature is in July and August. The phase of soil temperature variation in deeper layer is lagged behind that of the shallower layer. The cooling of the soil is quite slow. However, the warming of the soil is fast in spring and summer. Such phenomena may be associated with the feedback processes of snow cover, albedo, long wave radiation and the heat of condensation. The change of yearly climate can be reflected in the depth of 40 cm at least. The variations of daily mean soil moisture in different depths have no pronounced change. The variations of monthly mean soil moisture in different depths change distinctly. Soil moisture is dependent on summer precipitation.