Title: The Freezing-Thawing Processes and Soil Moisture-Energy Distribution in Permafrost Active Layer,Northern Tibet
Abstract: Based on the in-situ high-resolution observationsoil moisture and temperature data obtained in the permafrost active layer soil profilein Xainza County,Northern Tibet,the processes of freezing-thawingand distribution characteristics of soil energy and moisture on season shift were discussed. The results show that: 1) the process of soil seasonally freezing-thawing strongly depended on the soil temperature,the soil temperature in active layer shows a cycle variation and lag with air temperature,and the variation range is decreased with the increase of soil depth. 2) There are 109 ~ 123 days that soil profile was completely frozen,the daily freeing-thawing cycle occurs mainly in surface soil layer( 0 ~ 10 cm). According to the characteristics of different periods,the freezing-thawing cycle could be divided into 4 stages. 3) Affected by freezing-thawing cycle,the curve of un-frozen soil moisture showsdecreasing-at the lowest-increasingshape,the trend matched with the change of soil temperature. 4) The processes of freezing-thawing could maintain soil moisture from restraining soil evaporation,which may play an important role in the seasonal shift,carbon and nitrogen cycle of alpine grassland ecosystem in Northern Tibet.
Publication Year: 2014
Publication Date: 2014-01-01
Language: en
Type: article
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Cited By Count: 4
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