The analysis based on the
ground temperature at different depths at
D105 site,Qinghai\|Tibetan Plateau showed that the variation of daily mean ground temperature at different depths has a one\|year period.The variation is a sine curve.The fluctuations of the ground temperature in shallower layers are larger than that in deeper layers.However,although the fluctuation of ground temperature in summer is a little bit larger than that in winter for the same layer,the difference is not large.On surface,and at \{0\^05 m\} and \{0\^2 m,\}the variation amplitude of the daily
maximum ground temperature is larger than that of the daily
minimum ground temperature.The maximum daily
range of surface ground temperature in the study period is 60\^4℃.The maximum ground temperature on surface is 39\^7℃ and the minimum is -16\^5℃.The daily range of ground temperature in summer season is larger than that in winter and it decreased as the depth increased.There is no evident daily range of ground temperature in \{80 cm.\} Meanwhile,the variation trends of the daily maximum ground temperture and the daily minimum ground temperature are different.The snow
cover might affect the daily maximum ground temperature,daily minimum ground temperature and the daily range of the ground temperature.The relative thick snow cover can lead to decrease of the nocturnal long wave radiation on surface and prevent from drop of the minimum ground temperature.Meanwhile,the more important role played by the snow cover is to weaken the short wave radiation received on surface at daytime due to the sudden increase of albedo.This makes the maximum ground temperature on surface decrease substantially.The dual roles of the relatively thick smow cover contribute to the decreasing range of ground temperature.Anyway,the variation of the mean daily ground temperature is not so significant.Due to short of detailed snow cover data in the northern Tibetan Plateau,the above explanation needs further study.
More abstracts about the ANALYSIS OF GROUND TEMPERATURE AT D105 SITE ON NORTHERN SLOPE OF THE TANGGULA MOUNTAIN, QINGHAI-T