8 Microbial ecology of Alpine frozen ground: the Qinghai-Tibet Plateau

Raindrop size distribution (DSD) can reflect the fundamental microphysics of precipitation and provide an accurate estimation of its amount and characteristics; however, there are few observations and investigations of DSD in cold, mountainous regions. We used the second-generation particle size and velocity disdrometer Parsivel2 to establish a quality control scheme for raindrop spectral data obtained for the Qinghai–Tibet Plateau in 2015. This scheme included the elimination of particles in the lowest two size classes, particles >10 mm in diameter and rain rates <0.01 mm∙h−1. We analyzed the DSD characteristics for different types of precipitation and rain rates in both permafrost regions and regions with seasonally frozen ground. The precipitation in the permafrost regions during the summer were mainly solid with a large particle size and slow fall velocity, whereas the precipitation in the regions with seasonally frozen ground were mainly liquid. The DSD of snow had a broader drop spectrum, the largest particle size, the slowest fall velocity, and the largest number of particles, followed by hail. Rain and sleet shared similar DSD characteristics, with a smaller particle size, slower velocity, and smaller number of particles. The particle concentration for different classes of rain rate decreased with an increase in particle size and decreased gradually with an increase in rain rate. Precipitation with a rain rate >2 mm∙h−1 was the main contributor to the annual precipitation. The dewpoint thresholds for snow and rain in permafrost regions were 0 and 1.5 °C, respectively. The dewpoint range 0–1.5 °C was characterized by mixed precipitation with a large proportion of hail. This study provides valuable DSD information on the Qinghai–Tibet Plateau and can be used as an important reference for the quality control of raindrop spectral data in regions dominated by solid precipitation.

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Thermal State of Frozen Ground along National Highway No. 214 from Xi'ning to Yushu on the Northeastern Qinghai-Tibet Plateau, China

Cold Regions Engineering 2012 ◽

10.1061/9780784412473.017 ◽

2012 ◽

Author(s):

D. L. Luo ◽

H. J. Jin ◽

L. Lin

Keyword(s):

Thermal State ◽

Tibet Plateau ◽

Frozen Ground ◽

National Highway ◽

Qinghai Tibet Plateau

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Investigation of a Small Landslide in the Qinghai-Tibet Plateau by InSAR and Absolute Deformation Model

Remote Sensing ◽

10.3390/rs11182126 ◽

2019 ◽

Vol 11 (18) ◽

pp. 2126 ◽

Cited By ~ 3

Author(s):

Hao ◽

Wu ◽

Hu ◽

Zou ◽

...

Keyword(s):

Time Series ◽

Conceptual Model ◽

Progressive Failure ◽

Sar Interferometry ◽

Tibet Plateau ◽

Small Scale ◽

Deformation Model ◽

Frozen Ground ◽

Small Baseline ◽

Qinghai Tibet Plateau

Landslides are one of the major geohazards in the Qinghai-Tibet Plateau, and have recently increased in both frequency and size. SAR interferometry (InSAR) has been widely applied in landslide research, but studies on monitoring small-scale landslides are rare. In this study, we investigated the performance of Small Baseline Subsets method (SBAS) in monitoring small-scale landslide and further developed a new deformation model to obtain the absolute deformation time series. The results showed that SBAS could well capture the small-scale landslide characteristics including spatiotemporal abnormal displacement and progressive failure processes. The newly developed absolute deformation model further detected the process of landslide details, such as instances of noticeable creeps induced by rainfall and snowmelt. Finally, a conceptual model of the kinematics-based failure mechanism for small-scale landslide was proposed. This study extended the monitoring capability of InSAR and improved our knowledge on the deformation in the frozen ground regions.

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Difference between near-surface air, land surface and ground surface temperatures and their influences on the frozen ground on the Qinghai-Tibet Plateau

Geoderma ◽

10.1016/j.geoderma.2017.09.037 ◽

2018 ◽

Vol 312 ◽

pp. 74-85 ◽

Cited By ~ 33

Author(s):

Dongliang Luo ◽

Huijun Jin ◽

Sergey S. Marchenko ◽

Vladimir E. Romanovsky

Keyword(s):

Land Surface ◽

Ground Surface ◽

Tibet Plateau ◽

Frozen Ground ◽

Near Surface ◽

Surface Temperatures ◽

Qinghai Tibet Plateau

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Changes in frozen ground in the Source Area of the Yellow River on the Qinghai–Tibet Plateau, China, and their eco-environmental impacts

Environmental Research Letters ◽

10.1088/1748-9326/4/4/045206 ◽

2009 ◽

Vol 4 (4) ◽

pp. 045206 ◽

Cited By ~ 111

Author(s):

Huijun Jin ◽

Ruixia He ◽

Guodong Cheng ◽

Qingbai Wu ◽

Shaoling Wang ◽

...

Keyword(s):

Environmental Impacts ◽

Yellow River ◽

Source Area ◽

Tibet Plateau ◽

The Yellow River ◽

Frozen Ground ◽

Qinghai Tibet Plateau

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Study on the Freeze-Thaw Process of the Lining Structures of a Tunnel on Qinghai-Tibet Plateau with the Consideration of Lining Frost Damage

Advances in Materials Science and Engineering ◽

10.1155/2021/4921365 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Hong Yu ◽

Kun Zhang ◽

Xiaoming Zhu ◽

Zhizhuo Tian ◽

Qinglong Zhang

Keyword(s):

Tensile Stress ◽

Principal Stress ◽

Tibet Plateau ◽

Absolute Maximum ◽

Insulation Layer ◽

Road Tunnel ◽

Frozen Ground ◽

Freeze Thaw ◽

Lining Structure ◽

Qinghai Tibet Plateau

In seasonally frozen ground, there are many frost problems in highway road tunnel after its excavation due to the heat exchange between the cold air and lining structure inside the tunnel. To mitigate these frost-related damages, thermal insulation layer is widely used at entrance and exit sections of the tunnel. In this study, a coupled mathematical model of heat, moisture, and stress was built for tunnels in seasonally permafrost regions. Then, based on the field-observed air temperature inside a roadway tunnel at Altun Mountain on the Qinghai-Tibet Plateau (QTP), seasonal freeze-thaw process of the surrounding rocks (SR) and lining structures were numerically investigated with the consideration of insulation methods: without insulation (WTIL) and laying the insulation layer on the inner surface of the second lining structure (STIL). Combined with the principle of Miner damage accumulation, the stress regimes of the lining structures of tunnel were investigated in WTIL and STIL. The results show that there was a significantly thermal disturbance of the SR after the tunnel excavation. In the 5th year of the operation period, the maximum seasonal freeze depth (MSFD) of the SR can reach 1.6 m at the vault of the arch and that at the inverted arch was only 1.0 m due to the pavement inside the tunnel. Then, both the absolute maximum value of the maximum principal stress (MAPS) and minimum principal stress (MIPS) in cold season were bigger than those in warm season comparing the value of the stress filed of the lining structure. In the same way, both the MAPS and MIPS of the lining structure in WTIL are bigger than those in STIL in numerical simulation. The positions of the maximum tensile stress of the primary lining structure in STIL and WTIL were inverted arch. For the lining structures, the greater tensile stress was generally harmful. Thus, the inverted arch of the tunnel should be laid on the insulation layer.

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