摘要
改则地区地处青藏高原腹地，气候寒冷干燥，位于青藏高原大片连续多年冻土南界附近．2010年“青藏高原多年冻土本底调查”项目在改则地区采用坑探、物探和钻探等多种方法对区域内多年冻土开展了大规模野外考察工作．根据现场钻探资料和后来的地温观测资料，并结合坑探和物探资料对改则地区多年冻土特征进行分析，结果显示：改则地区多年冻土上限深度在2．6～8．5 m之间，部分地区存在融化夹层；多年冻土含冰量在12％～35％之间，主要为多冰冻土，而且一般仅在上限附近发育有高含冰量多年冻土；多年冻土温度普遍较高，在－1．5～0℃之间；多年下限深度一般小于60 m，部分地区甚至在10 m左右；多年冻土分布的下界海拔高度约为4700 m，海拔5100 m以上区域普遍发育有多年冻土；区域内多年冻土特征受局地因素影响明显，特别是与坡向、植被覆盖、岩性和含水量等关系密切；现场记录资料和后来的测温资料都显示改则地区部分多年冻土正处于退化状态．
Gerze County in the inland of the Tibetan Plateau is located on the southern boundary of the continu-ous permafrost over the Tibetan Plateau.A field survey was carried out by the expedition,Qinghai-Tibet Plateau Permafrost Background Survey,in October and November,2010,when pitting,geophysical exploration and drilling were performed to learn about the permafrost in Gerze.Characteristics of permafrost are analyzed based on the records of drill exploration and borehole temperature measurements.It is found that permafrost table is at the depth of 2.6-8.5 m with some thawed samdwich beneath.Permafrost is mainly icy and ice-rich.The ice content is between 12% and 35% by weight.Soil with high ice content is only found at the top of permafrost. Permafrost temperature is relatively high with the mean annual ground temperature of -1 .5 -0 ℃.Permafrost base is mostly at the depth not more than 60 m and partly less than 10 m.The lower boundary of permafrost is at the altitude about 4 700 m.Continous permafrost develops at the elevation above 4 990 m.Characteristics of permafrost are controlled by local factors,such as aspect,vegetation,soil attribute and water content.Field drill exploration and borehole temperature monitor indicate that permafrost is degrading in Gerze.
出处
《冰川冻土》
CSCD
北大核心
2015年第6期1453-1460,共8页
Journal of Glaciology and Geocryology
基金
国家重大科学研究计划项目(2013CBA01803)
国家自然科学基金项目(41101069)
中国科学院"百人计划"(51Y251571)
冰冻圈科学国家重点实验室自主课题(SKLCS-ZZ-2016)资助
关键词
多年冻土特征
改则
青藏高原
characteristics of permafrost
Gerze County
Tibetan Plateau
