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基于黄河源区2010~2012年4个监测场地的土壤温度和水分资料,分析了多年冻土活动层和季节冻土冻融过程时空差异.结果表明,4个场地地温和冻土厚度不同,活动层底板或最大季节冻结深度年平均温度(TTOP)分别为:查拉坪场地(CLP)?1.9℃,扎陵湖场地(ZLH)?0.9℃,麻多乡场地(MDX)–0.4℃,鄂陵湖场地(ELH)1.1℃.冻融过程差异与冻土温度和TTOP相关,随着TTOP升高,融化开始时间提前,CLP在6月初,ZLH在5月中下旬,MDX在5月初,ELH在4月上旬;冻结开始时间滞后,CLP为10月初,ZLH为10月上中旬,MDX为10月中旬,ELH为10月中下旬;活动层整体冻结期随之减小,CLP为202 d,ZLH为130 d,MDX为100 d,ELH整体融化期为89 d.CLP和ZLH冻结融化过程均于年内完成,冻结过程表现为由上向下和由下向上双向进行.MDX冻结过程持续至次年1月末,但在冻结期末冻结速率很小,由下向上冻结因极微弱而呈单向进行.ELH冻结持续至次年5月初,出现季节冻结和季节融化过程并存格局;冻结过程单向进行,但融化呈现微弱的双向过程;6月下旬至7月初双向融化比较稳定.各场地随着TTOP升高,由下向上冻结速率相对由上向下的减慢,由下向上的冻结深度减小,融化过程相对冻结过程持续时间比值减小.总之,黄河源区活动层季节冻融过程与青藏高原其他地区有比较显著的差异.
Based on the data of soil temperature and moisture in the four monitoring sites in the source region of the Yellow River from 2010 to 2012, the spatio-temporal variations of the frozen and thawed soils of the permafrost and the seasonal frozen soil were analyzed. The results showed that the geothermal and frozen soil had different thicknesses, The average floor temperature of the bottom plate or the maximum seasonal freezing depth (TTOP) were: Celazpur site (CLP) 1.9 ℃, Zhalong lake site ZLH 0.9 ℃, MDX -0.4 ℃, ELH is 1.1 ℃ .The difference of freeze-thaw process is related to permafrost temperature and TTOP. With the increase of TTOP, the onset of thawing begins earlier. In early June of CLP, in mid-to-late of ZLH and in early May of MDX, ELH In the beginning of April, the freezing time lag, CLP was in early October, ZLH was mid-October, MDX was mid-October, and ELH was mid-to-late October. The overall freezing period of active layer was reduced, CLP was 202 days, ZLH was 130 d, MDX was 100 d, ELH overall melting period was 89 d.CLP and ZLH freeze thawing process were completed during the year, the freezing process showed up and down from the bottom up two-way.MDX freezing process until At the end of January of the year, but at the end of the freeze period, the freezing rate was very small and the freeze from bottom to top was one-way due to the extremely weakness. The ELH freeze lasted until early May next year, The seasonal freezing and seasonal thawing process coexist in the process of freezing, the freezing process is unidirectional, but the thawing process shows a faint two-way process and the two-way thawing process is relatively stable from late June to early July. The decrease of the freezing depth from bottom to top and the decrease of the duration of the thawing process relative to the freezing process, in short, the seasonal freezing and thawing process of the active layer in the source region of the Yellow River has a significant difference from that of other parts of the Qinghai-Tibet Plateau.