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Influence of slope direction on the permafrost degradation: a case study in Qinghai-Tibetan Plateau
  • +4
  • Xingwen Fan,
  • Zhanju Lin,
  • fujiun niu,
  • Zeyong Gao,
  • Jing Luo,
  • Aiyu Lan,
  • MiaoMiao Yao
Xingwen Fan
Chinese Academy of Sciences
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Zhanju Lin
Northwest Institute of Eco-Environment and Resources State Key Laboratory of Frozen Soil Engineering
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fujiun niu
Northwest Institute of Eco-Environment and Resources State Key Laboratory of Frozen Soil Engineering
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Zeyong Gao
Northwest Institute of Eco-Environment and Resources State Key Laboratory of Frozen Soil Engineering
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Jing Luo
Northwest Institute of Eco-Environment and Resources State Key Laboratory of Frozen Soil Engineering
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Aiyu Lan
Chinese Academy of Sciences
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MiaoMiao Yao
Chinese Academy of Sciences
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Abstract

Slope direction affects permafrost degradation because of its influence on the surface energy balance. The ground thermal difference between slopes of differing aspect is known, however there are few detailed reports on differences in soil temperature, humidity, and radiation from slopes in permafrost areas that caused permafrost degradation. In this study variations in air and ground thermal regime were compared at two sloping sites with opposing aspect in a permafrost region of the Qinghai-Tibetan Plateau (QTP). The results indicate that air temperatures (Ta) were similar at both sites in September 2016-19. However, ground temperatures, including the ground surface temperature (Ts), the temperature near the permafrost surface (Tps), and the permafrost temperature at 5.0 m depth (Tg), and soil moisture content within the active layer differed greatly between sites. The mean annual Ts, Tps, and Tg over three years (2016-19) were 1.3-1.4 ℃ higher at the sunny slope than at the shady slope. The near-surface soil moisture content during the thawing season was 10-13% lower at the sunny slope (~22-27%) than the shady slope (~35-38%), and was significantly and negatively correlated with ground temperature. Shortwave downward radiation (DR) at the sunny slope was higher than at the shady slope. However, net radiation (Rn) was lower at the sunny slope due to the greater surface albedo at the site. The results highlight a complex spatial pattern of ground thermal conditions in mountainous permafrost regions, help define the climate-permafrost relation in the region, and for understanding permafrost degradation on a local scale.

Peer review status:IN REVISION

25 May 2021Submitted to Land Degradation & Development
27 May 2021Assigned to Editor
27 May 2021Submission Checks Completed
30 May 2021Reviewer(s) Assigned
11 Jun 2021Review(s) Completed, Editorial Evaluation Pending
12 Jun 2021Editorial Decision: Revise Major