State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Frozen Soils Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
Sci Total Environ. 2017 Mar 1;581-582:472-485. doi: 10.1016/j.scitotenv.2016.12.155. Epub 2017 Jan 2.
Beiluhe basin is underlain by warm and ice-rich permafrost, and covered by vegetation and soils characteristic of the Qinghai-Tibet Plateau. A field monitoring network was established to investigate permafrost conditions and to assess potential impacts of local factors and climate change. This paper describes the spatial variations in permafrost conditions from instrumented boreholes, controlling environmental factors, and recent thermal evolution of permafrost in the basin. The study area was divided into 10 ecotypes using satellite imagery based classification. The field investigations and cluster analysis of ground temperatures indicated that permafrost underlies most of the ground in swamp meadow, undisturbed alpine meadow, degrading alpine meadow, and desert alpine grassland, but is absent in other cover types. Permafrost-ecotope relations examined over a 2-year (2014-2016) period indicated that: (i) ground surface temperatures varied largely among ecotopes; (ii) annual mean ground temperatures ranged from -1.5 to 0°C in permafrost, indicating sensitive permafrost conditions; (iii) active-layer thicknesses ranged from 1.4m to 3.4m; (iv) ground ice content at the top of permafrost is high, but the active-layer soil is relatively dry. Long-term climate warming has driven thermal changes to permafrost, but ground surface characteristics and soil moisture content strongly influence the ground thermal state. These factors control local-scale spatial variations in permafrost conditions. The warm permafrost in the basin is commonly in thermal disequilibrium, and is sensitive to future climate change. Active-layer thicknesses have increased by at least 42cm and the mean annual ground temperatures have increased by up to 0.2°C in the past 10years over the basin. A permafrost distribution map was produced based on ecotypes, suggesting that permafrost underlies 64% of the study region.
贝里湖盆地被温暖且富冰的多年冻土所覆盖，并被青藏高原特有的植被和土壤所覆盖。建立了一个野外监测网络，以调查多年冻土条件，并评估当地因素和气候变化的潜在影响。本文描述了仪器化钻孔中的多年冻土条件的空间变化、控制环境因素以及盆地多年冻土的近期热演化。研究区利用卫星图像分类法分为 10 种生态型。地面温度的野外调查和聚类分析表明，多年冻土覆盖了沼泽草甸、未受干扰的高山草甸、退化高山草甸和沙漠高山草原的大部分地面，但在其他覆盖类型中则不存在。经过两年（2014-2016 年）的多年冻土-生态型关系研究表明：（i）各生态型之间的地面温度差异很大；（ii）多年冻土内的年平均地面温度在-1.5 至 0°C 之间，表明多年冻土条件敏感；（iii）活动层厚度在 1.4 至 3.4 米之间；（iv）多年冻土顶部的地中冰含量较高，但活动层土壤相对干燥。长期气候变暖导致多年冻土发生热变化，但地面特征和土壤含水量强烈影响地面热状态。这些因素控制着多年冻土条件的局地空间变化。盆地内温暖的多年冻土通常处于热不平衡状态，对未来气候变化敏感。在过去的 10 年中，整个盆地的活动层厚度增加了至少 42 厘米，年平均地面温度增加了多达 0.2°C。根据生态型制作了多年冻土分布图，表明研究区的 64%都有多年冻土覆盖。
