Thermal regime of warm-dry permafrost in relation to ground surface temperature in the Source Areas of the Yangtze and Yellow rivers on the Qinghai-Tibet Plateau, SW China

Dongliang Luo; Huijun Jin; Qingbai Wu; Victor F Bense; Ruixia He; Qiang Ma; Shuhui Gao; Xiaoying Jin; Lanzhi Lü

doi:10.1016/j.scitotenv.2017.09.083

Thermal regime of warm-dry permafrost in relation to ground surface temperature in the Source Areas of the Yangtze and Yellow rivers on the Qinghai-Tibet Plateau, SW China

Sci Total Environ. 2018 Mar 15:618:1033-1045. doi: 10.1016/j.scitotenv.2017.09.083. Epub 2017 Oct 31.

Authors

Dongliang Luo¹, Huijun Jin², Qingbai Wu³, Victor F Bense⁴, Ruixia He³, Qiang Ma³, Shuhui Gao³, Xiaoying Jin³, Lanzhi Lü³

Affiliations

¹ State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China. Electronic address: luodongliang@lzb.ac.cn.
² State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China.
³ State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
⁴ State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Hydrology and Quantitative Water Management Group Department of Environmental Sciences, Wageningen University, Wageningen, Netherlands.

PMID: 29092743
DOI: 10.1016/j.scitotenv.2017.09.083

Abstract

Ecology, hydrology, and natural resources in the source areas of the Yangtze and Yellow rivers (SAYYR) are closely linked to interactions between climate and permafrost. However, a comprehensive study of the interactions is currently hampered by sparsely- and unevenly-distributed monitoring sites and limited field investigations. In this study, the thermal regime of warm-dry permafrost in the SAYYR was systematically analyzed based on extensive data collected during 2010-2016 of air temperature (T_a), ground surface temperature (GST) and ground temperature across a range of areas with contrasting land-surface characteristics. Mean annual T_a (MAAT) and mean annual GST (MAGST) were regionally averaged at -3.19±0.71°C and -0.40±1.26°C. There is a close relationship between GST and T_a (R²=0.8477) as obtained by a linear regression analysis with all available daily averages. The mean annual temperature at the bottom of the active layer (T_TOP) was regionally averaged at -0.72±1.01°C and mostly in the range of -1.0°C and 0°C except at Chalaping (~-2.0°C). Surface offset (MAGST-MAAT) was regionally averaged at 2.54±0.71°C. Thermal offset (T_TOP-MAGST) was regionally averaged at -0.17±0.84°C, which was generally within -0.5°C and 0.5°C. Relatively consistent thermal conductivity between the thawed and frozen states of the soils may be responsible for the small thermal offset. Active layer thickness was generally smaller at Chalaping than that on other parts of the QTP, presumably due to smaller climatic continentality index and the thermal dampening of surface temperature variability under the presence of dense vegetation and thick peaty substrates. We conclude that the accurate mapping of permafrost on the rugged elevational QTP could be potentially obtained by correlating the parameters of GST, thermal offset, and temperature gradient in the shallow permafrost.

Keywords: Ground surface temperature; Permafrost-climate relationship; Qinghai-Tibet Plateau (QTP); The source areas of the Yangtze and Yellow rivers (SAYYR); Warm-dry permafrost.