摘要
在柱坐标下,运用带相变的数值热传导模型,预测了千年尺度上热融湖对多年冻土退化的影响。预测结果表明,受热融湖的影响,湖底下部及周围多年冻土温度状态发生了较大变化。在湖深相同的情况下,湖底年平均温度越高,对多年冻土的热扰动越明显。当湖底年平均温度等于0℃时,湖底下部及周围多年冻土一般不会形成融化层,只可能引起地温升高;当湖底年平均温度大于0℃时,多年冻土不但温度升高,上限下移,而且可能形成融化层,最终导致多年冻土可能被融穿。湖底年平均温度越高,地温增加越快,融穿多年冻土的时间越短。在湖底年平均温度相同的情况下,水深差异对多年冻土退化的影响不明显。
Under rectangular coordinate system, a heat transfer model with phase change was used to predict influence of thaw lake on permafrost degradation in the Beiluhe Basin on the Qinghai-Tibet Plateau. results show that the presence of a water body constitutes a heat source and releases heat energy to the The the permafrost beneath and around lake, giving rise to the significant changes in ground temperature regime. For the same deep lakes, the mean annual lake-bottom temperature is one of the important factors that decide whether the lake has impacted on the permafrost. The higher annual average lake-bottom temperature occurs at the lake-bottom, the more obviously thermal disturbance may happen in permafrost beneath and around it. When the mean annual lake bottom temperature equals to 0℃, talik （perennial thaw layer） is impossible occurrence beneath and around lake-bottom, however the ground temperatures would gradual increase. When the mean annual lake bottom temperature is higher than 0℃, temperature of permafrost will increase and upper limit will decrease. Talik will develop, finally resulting in the thawing of the permafrost. The higher temperature at the lake-bottom, the quicker ground temperature increases in permafrost, and the shorter the time for the permafrost to melt. Under conditions of the same annual mean temperatures at bottom of the lake, difference of water depths has no distinct influence on the permafrost degradation.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2013年第5期737-746,共10页
Acta Geologica Sinica
基金
国家自然科学基金重点项目(编号41030741)
科技部973计划(编号2012CB026101)
中科院寒旱所人才基金
冻土工程国家重点实验室自主项目(编号SKLFSE-ZQ-14)共同资助的成果
关键词
青藏高原
热融湖
多年冻土退化
数值模拟
Qinghai-Tibet Plateau
thaw lake
permafrost degradation
numerous simulation
