Water regime shifts in the active soil layer of the Qinghai–Tibet Plateau permafrost region, under different levels of vegetation

Geoderma ◽  
2009 ◽  
Vol 149 (3-4) ◽  
pp. 280-289 ◽  
Author(s):  
Wang Genxu ◽  
Li Shengnan ◽  
Hu Hongchang ◽  
Li Yuanshou
Keyword(s):  
Water Regime ◽  
Soil Layer ◽  
Regime Shifts ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Qinghai Tibet Plateau ◽  
Different Levels

Dynamic Behavior of Pile Foundation in Frozen and Thawing Soil

2011 ◽  
Vol 105-107 ◽  
pp. 1391-1399
Author(s):  
Hao Li ◽  
Wei Nan Lu
Keyword(s):  
Pile Foundation ◽  
Dynamic Stiffness ◽  
Soil Layer ◽  
Tibet Plateau ◽  
Triaxial Tests ◽  
Permafrost Region ◽  
Harmonic Load ◽  
Stiffness And Damping ◽  
Qinghai Tibet Plateau ◽  
Temperature Dynamic

Permafrost is widespread in China, especially in Northeast China and the Qinghai-Tibet Plateau. Regions like Qinghai-Tibet Plateau have the most strenuous crustal movement. Therefore, earthquake-resistance of structures in permafrost region is an important issue. Furthermore, the permafrost will degenerate gradually as global warming mounts up. In some regions permafrost thickness tends to attenuate. Most bridge designs adopt pile foundation in order to reduce the effects of instable frost. The deterioration of frost leads to degradation of anti-seismic performance of bridges’ pile foundations. Pile-soil dynamic interaction numerical analysis models are established based on data of indoor low-temperature dynamic triaxial tests. Studies are performed on the dynamic stiffness and damping characters and the influencing factors of pile foundation under vertical harmonic load in frozen and thawing soil. The result shows that the dynamic response of the pile decreases along the depth, and the frictional resistance around the pile mainly distributes along the upper half of the pile, and the dynamic stiffness and damping of the pile are affected by temperature. Dynamic stiffness increases as temperature goes down, whereas the decrease of the temperature of frozen soil can notably lower the dynamic damping of the head of the pile. As the frequency of the dynamic load augments, the dynamic stiffness of the head increases marginally, whereas frequency has little influence on damping. The relative thickness of the frozen and thawing soil layer has considerable influence on dynamic stiffness, but negligible on damping.

Creep characteristics and process analyses of a thaw slump in the permafrost region of the Qinghai-Tibet Plateau, China

Geomorphology ◽  
2017 ◽  
Vol 293 ◽  
pp. 1-10 ◽  
Author(s):  
Zhe Sun ◽  
Yibo Wang ◽  
Yan Sun ◽  
Fujun Niu ◽  
GuoyuLi ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Permafrost Region ◽  
Creep Characteristics ◽  
Qinghai Tibet Plateau

Diversity and distribution of alkaliphilic psychrotolerant bacteria in the Qinghai–Tibet Plateau permafrost region

Extremophiles ◽  
2007 ◽  
Vol 11 (3) ◽  
pp. 415-424 ◽  
Author(s):  
Gaosen Zhang ◽  
Xiaojun Ma ◽  
Fujun Niu ◽  
Maoxing Dong ◽  
Huyuan Feng ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Permafrost Region ◽  
Psychrotolerant Bacteria ◽  
Qinghai Tibet Plateau

scholarly journals Analysis of Permafrost Region Coherence Variation in the Qinghai–Tibet Plateau with a High-Resolution TerraSAR-X Image

2018 ◽  
Vol 10 (2) ◽  
pp. 298 ◽  
Author(s):  
Zhengjia Zhang ◽  
Chao Wang ◽  
Hong Zhang ◽  
Yixian Tang ◽  
Xiuguo Liu
Keyword(s):  
High Resolution ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Qinghai Tibet Plateau

scholarly journals Brief Communication: Evaluation and comparisons of permafrost map over Qinghai-Tibet Plateau based on inventory of in-situ evidence

2018 ◽  
Author(s):  
Bin Cao ◽  
Tingjun Zhang ◽  
Qinghai Wu ◽  
Yu Sheng ◽  
Lin Zhao ◽  
...  
Keyword(s):  
Controlling Factors ◽  
In Situ Measurements ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Improved Method ◽  
Limited Evidence ◽  
Wide Range ◽  
Communication Evaluation ◽  
Qinghai Tibet Plateau

Abstract. Many maps have been produced to estimate permafrost distribution over the Qinghai-Tibet Plateau, however, the evaluation and comparisons of them are poorly understood due to limited evidence. Using a large number data from various sources, we present the inventory of permafrost presence/absence with 1475 sites/plots over the QTP. Based on the in-situ measurements, our evaluation results showed a wide range of map performance with the overall accuracy of about 59–82 %, and the estimated permafrost region (1.42–1.84 × 106 km2) and area (0.76–1.25 × 106 km2) are extremely large. The low agreement in areas near permafrost boundary and fragile landscapes require improved method considering more controlling factors at both medium-large and local scales.

scholarly journals Analysis on the Temporal and Spatial Characteristics of the Shallow Soil Temperature of the Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Yujie Li ◽  
Cunjie Zhang ◽  
Zhenchao Li ◽  
Liwei Yang ◽  
Xiao Jin ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Observational Data ◽  
Temperature Increase ◽  
Soil Layer ◽  
Tibet Plateau ◽  
Shallow Soil ◽  
Increasing Trend ◽  
Temporal And Spatial ◽  
Region 10 ◽  
Qinghai Tibet Plateau

Abstract Shallow soil refers to the soil layer within 50 cm underground. Shallow soil temperature (ST) affects many processes that occur in the soil. Therefore, the study of shallow ST is of great significance in understanding energy, hydrological cycles and climate change. This work collected the observational data from 141 meteorological stations on the Qinghai-Tibet Plateau from 1981 to 2020, analyzed the ST as well as its temporal and spatial change characteristics at different levels. The results show that: 1) The shallow ST has a gradually increasing trend from north to south, from west to east. From the perspective of time characteristics, the increasing trend is obvious. The temperature increase of 0–20 cm (the surface layer of the shallow soil) is roughly the same. The average annual is 9.15–9.57 ℃, the interdecadal variabilities are 0.49–0.53 K/10a. The average annual of 40 cm (the bottom layer) is 8.69 ℃, the interdecadal variability reaches by 0.98 K/10a; 2) Judging from the 12 regions of 20 cm, the temperature increase trend is obvious, but there are certain regional differences. The average value ranges from 4.3 ℃ (region 4, Qaidam Plateau) to 18.1 ℃ (region 10, Southeast Qinghai-Tibet Plateau), the difference is nearly 14 K. The standard deviation ranges from 0.38 K (region 10) to 0.82 K (region 11, Northern Qiangtang Plateau); 3) The results of the reanalysis data are lower than the observational data. This work is significant for understanding the characteristics of the ST evolution and the land-atmosphere interaction on the Qinghai-Tibet Plateau.

scholarly journals Freeze-thaw processes of active layer regulate soil respiration of alpine meadow in the permafrost region of the Qinghai-Tibet Plateau

2019 ◽  
Author(s):  
Junfeng Wang ◽  
Qingbai Wu ◽  
Ziqiang Yuan ◽  
Hojeong Kang
Keyword(s):  
Soil Respiration ◽  
Active Layer ◽  
Alpine Meadow ◽  
Water Status ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Permafrost Degradation ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Qinghai Tibet Plateau

Abstract. Freezing and thawing action of the active layer plays a significant role in soil respiration (Rs) in permafrost regions. However, little is known about how the freeze-thaw process regulates the Rs dynamics in different stages for the alpine meadow underlain by permafrost on the Qinghai-Tibet Plateau (QTP). We conducted continuous in-situ measurements of Rs and freeze-thaw process of the active layer at an alpine meadow site in the Beiluhe permafrost region of QTP to determine the regulatory mechanisms of the different freeze-thaw stages of the active layer on the Rs. We found that the freezing and thawing process of active layer modified the Rs dynamics differently in different freeze-thaw stages. The mean Rs ranged from 0.56 to 1.75 μmol/m2s across the stages, with the lowest value in the SW stage and highest value in the ST stage; and Q10 among the different freeze-thaw stages changed greatly, with maximum (4.9) in the WC stage and minimum (1.7) in the SW stage. Patterns of Rs among the ST, AF, WC, and SW stages differed, and the corresponding contribution percentages of cumulative Rs to annual total Rs were 61.54, 8.89, 18.35, and 11.2 %, respectively. Soil temperature (Ts) was the most important driver of Rs regardless of soil water status in all stages. Our results suggest that as the climate warming and permafrost degradation continue, great changes in freeze-thaw process patterns may trigger more Rs emissions from this ecosystem because of prolonged ST stage.

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