scholarly journals A projection of permafrost degradation on the Tibetan Plateau during the 21st century

2012 ◽  
Vol 117 (D5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Donglin Guo ◽  
Huijun Wang ◽  
Duo Li
Keyword(s):  
Tibetan Plateau ◽  
21St Century ◽  
The Tibetan Plateau ◽  
Permafrost Degradation

scholarly journals InSAR time series analysis of seasonal surface displacement dynamics on the Tibetan Plateau

2019 ◽  
Author(s):  
Eike Reinosch ◽  
Johannes Buckel ◽  
Jie Dong ◽  
Markus Gerke ◽  
Jussi Baade ◽  
...  
Keyword(s):  
Time Series ◽  
Tibetan Plateau ◽  
Time Series Analysis ◽  
Surface Displacement ◽  
The Tibetan Plateau ◽  
Permafrost Degradation ◽  
Nam Co ◽  
Freeze Thaw ◽  
Series Analysis ◽  
Spatial Coverage

Abstract. Climate change and the associated rise in air temperature have affected the Tibetan Plateau to a significantly stronger degree than the global average over the past decades. This has caused deglaciation, permafrost degradation and increased precipitation, heavily changing the water balance of this region. Surface displacement processes are likely to change as the ground continues to warm up and as such it is vital to understand both seasonal and interannual processes dynamics. The Nam Co area is well suited to studying these processes via Interferometric Synthetic Aperture Radar (InSAR) time series analysis, due to its lack of higher vegetation and relatively thin snow cover. The short revisit time of the Sentinel-1 system further reduces the risk of temporal decorrelation, making it possible to produce surface displacement models with good spatial coverage. We created three different surface displacement models to study freeze-thaw processes, seasonal sliding and linear creep. Most slopes of the area are unstable, with velocities of 8 to 17 mm yr−1, and some landforms reach velocities of up to 18 cm yr−1. The monsoonal climate accelerates those movements during the summer months through high temperatures and heavy rainfall. The fastest moving landforms, some of which have been identified as rock glaciers, do not follow this seasonal pattern of accelerated velocity in summer, instead they follow a linear sliding pattern. It is unclear if this linearity is connected to the ice content in those landforms. Flat regions at Nam Co are mostly stable on a multiannual scale but some experience subsidence, which could be caused by permafrost degradation. We observe a very clear seasonal freeze-thaw cycle in the valleys, where thawing and subsequent freezing of the active layer cause a vertical oscillation of the ground of up to a few centimeters, especially near streams and other water bodies.

Review on global change status and its impacts on the Tibetan Plateau environment

2019 ◽  
Vol 12 (6) ◽  
pp. 917-930 ◽  
Author(s):  
Aamir Latif ◽  
Sana Ilyas ◽  
Yangjian Zhang ◽  
Yuqin Xin ◽  
Lin Zhou ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Global Change ◽  
Warming Trend ◽  
The Tibetan Plateau ◽  
Permafrost Degradation ◽  
Lake Area ◽  
Environmental Consequences ◽  
Belt And Road ◽  
Significant Temperature ◽  
Research Gap

Abstract The Tibetan Plateau (TP) holds fundamental ecological and environmental significances to China and Asia. The TP also lies in the core zone of the belt and road initiative. To protect the TP environment, a comprehensive screening on current ecological research status is entailed. The teased out research gap can also be utilized as guidelines for the recently launched major research programs, i.e. the second TP scientific expedition and silk and belt road research plan. The findings showed that the TP has experienced significant temperature increase at a rate of 0.2°C per decade since 1960s. The most robust warming trend was found in the northern plateau. Precipitation also exhibited an increasing trend but with high spatial heterogeneity. Changing climates have caused a series of environmental consequences, including lake area changes, glacier shrinkage, permafrost degradation and exacerbated desertification. The rising temperature is the main reason behind the glaciers shrinkage, snow melting, permafrost degradation and lake area changes on the TP and neighboring regions. The projected loss of glacial area on the plateau is estimated to be around 43% by 2070 and 75% by the end of the century. Vegetation was responsive to the changed environments, varied climates and intensified human activities by changing phenology and productivity. Future global change study should be more oriented toward integrating various research methods and tools, and synthesizing diverse subjects of water, vegetation, atmosphere and soil.

scholarly journals InSAR time series analysis of seasonal surface displacement dynamics on the Tibetan Plateau

2020 ◽  
Vol 14 (5) ◽  
pp. 1633-1650 ◽  
Author(s):  
Eike Reinosch ◽  
Johannes Buckel ◽  
Jie Dong ◽  
Markus Gerke ◽  
Jussi Baade ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Surface Displacement ◽  
Slope Instability ◽  
The Tibetan Plateau ◽  
Permafrost Degradation ◽  
Linear Pattern ◽  
Spatial Coverage ◽  
Rock Glaciers ◽  
Gravity Driven ◽  
Displacement Patterns

Abstract. Climate change and the associated rise in air temperature have affected the Tibetan Plateau to a significantly stronger degree than the global average over the past decades. This has caused deglaciation, increased precipitation and permafrost degradation. The latter in particular is associated with increased slope instability and an increase in mass-wasting processes, which pose a danger to infrastructure in the vicinity. Interferometric synthetic aperture radar (InSAR) analysis is well suited to study the displacement patterns driven by permafrost processes, as they are on the order of millimeters to decimeters. The Nyainqêntanglha range on the Tibetan Plateau lacks high vegetation and features relatively thin snow cover in winter, allowing for continuous monitoring of those displacements throughout the year. The short revisit time of the Sentinel-1 constellation further reduces the risk of temporal decorrelation, making it possible to produce surface displacement models with good spatial coverage. We created three different surface displacement models to study heave and subsidence in the valleys, seasonally accelerated sliding and linear creep on the slopes. Flat regions at Nam Co are mostly stable on a multiannual scale but some experience subsidence. We observe a clear cycle of heave and subsidence in the valleys, where freezing of the active layer followed by subsequent thawing cause a vertical oscillation of the ground of up to a few centimeters, especially near streams and other water bodies. Most slopes of the area are unstable, with velocities of 8 to 17 mm yr−1. During the summer months surface displacement velocities more than double on most unstable slopes due to freeze–thaw processes driven by higher temperatures and increased precipitation. Specific landforms, most of which have been identified as rock glaciers, protalus ramparts or frozen moraines, reach velocities of up to 18 cm yr−1. Their movement shows little seasonal variation but a linear pattern indicating that their displacement is predominantly gravity-driven.

scholarly journals Slight glacier reduction over the northwestern Tibetan Plateau despite significant recent warming

2016 ◽  
Author(s):  
Yetang Wang ◽  
Shugui Hou ◽  
Wenling An ◽  
Hongxi Pang ◽  
Yaping Liu
Keyword(s):  
Tibetan Plateau ◽  
21St Century ◽  
The Tibetan Plateau ◽  
Early 21St Century ◽  
Mountain Glaciers ◽  
Recent Warming ◽  
Kunlun Mountain ◽  
Western Kunlun ◽  
Significant Area ◽  
The Early 21St Century

Abstract. "Pamir–Karakoram–Western-Kunlun-Mountain (northwestern Tibetan Plateau) Glacier Anomaly" has been a topic of debate due to the balanced, or even slightly positive glacier mass budgets in the early 21st century. Here we focus on the evolution of glaciers on the western Kunlun Mountain and its comparison with those from other regions of the Tibetan Plateau. The possible driver for the glacier evolution is also discussed. Western Kunlun Mountain glaciers reduce in area by 0.12 % yr−1 from 1970s to 2007–2011. However, there is no significant area change after 1999. Averaged glacier thickness loss is 0.08 ± 0.09 m yr−1 from 1970s to 2000, which is in accordance with elevation change during the period 2003–2008 estimated by the ICESat laser altimetry measurements. These further confirm the anomaly of glaciers in this region. Slight glacier reduction over the northwestern Tibetan Plateau may result from more accumulation from increased precipitation in winter which to great extent protects it from mass reductions under climate warming during 1961–2000. Warming slowdown since 2000 happening at this region may further mitigate glacier mass reduction, especially for the early 21st century.

scholarly journals Growth of a high-elevation large inland lake, associated with climate change and permafrost degradation in Tibet

2009 ◽  
Vol 6 (4) ◽  
pp. 5445-5469 ◽  
Author(s):  
J. Liu ◽  
S. Kang ◽  
T. Gong ◽  
A. Lu
Keyword(s):  
Tibetan Plateau ◽  
High Elevation ◽  
Annual Runoff ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Permafrost Degradation ◽  
Lake Area ◽  
Pan Evaporation ◽  
Inland Lake ◽  
Precipitation Increase

Abstract. This study analyzed satellite images and long term climate variables from a high-elevation meteorological station (4730 m) and streamflow records to examine hydrological response of Nam Co Lake (4718 m), the largest lake on the Tibetan Plateau, over the last 50 years. The results show the lake area extended by 51.8 km2 (2.7% of the total area) when compared with the area in 1976. This change is associated with an annual precipitation increase of 65 mm (18.6%), annual and winter mean temperature increases of 0.9°C and 2.1°C respectively, an annual runoff increase of 20% and an annual pan evaporation decrease of about 2%, during the past 20 years. The year of the change point in annual precipitation, air temperature, annual pan evaporation and runoff occurred in 1971, 1983, 1997 and 1997, respectively. The timing of the lake growth corresponds with the abrupt increase in annual precipitation and runoff since the mid-1990s. This study suggests a strong positive water balance in the largest inland lake on the Tibetan Plateau.

scholarly journals Summer Temperature over the Tibetan Plateau Modulated by Atlantic Multidecadal Variability

2019 ◽  
Vol 32 (13) ◽  
pp. 4055-4067 ◽  
Author(s):  
Chunming Shi ◽  
Cheng Sun ◽  
Guocan Wu ◽  
Xiuchen Wu ◽  
Deliang Chen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
General Circulation ◽  
Ring Width ◽  
Circulation Model ◽  
The Tibetan Plateau ◽  
Positive Temperature ◽  
Permafrost Degradation ◽  
Atlantic Multidecadal Variability ◽  
Multidecadal Variability ◽  
Instrumental Records

Abstract Rapid warming has led to an aggregated environmental degradation over the Tibetan Plateau (TP) in the last few decades, including accelerated glacier retreat, early snowmelt, permafrost degradation, and forest fire occurrence. Attribution of this warming in recent decades has mainly been focused on anthropogenic forcing. Yet, linkages to the Atlantic multidecadal variability (AMV), an essential part of the climate system causing decadal to centennial fluctuations of temperature, remains poorly understood for the TP, especially at long time scales. Using well-replicated tree-ring width records, we reconstructed 358 years of summer minimum temperature (MinT) of the whole TP. This reconstruction matches the recent warming signal recorded since the 1980s, and captures 63% of the variance in 1950–2005 instrumental records. A teleconnection from the North Atlantic to the TP is further identified based in observations and simulations with an atmospheric general circulation model (AGCM). We propose that half of the multidecadal variability of TP summer MinT can be explained by the AMV over the past three and a half centuries. Both observations and AGCM simulations indicate that the AMV warm phase induces a zonal dipole response in sea level pressure across the Atlantic–Eurasia region, with anomalously high surface pressure and corresponding downward atmospheric motion over the TP. We propose that the descending motion during warm AMV phases causes negative rainfall and positive temperature anomalies over the TP. Our findings highlight that the AMV plays a role in the multidecadal temperature variability over the TP.

scholarly journals Numerical simulations of Gurenhekou Glacier on the Tibetan Plateau using a full-Stokes ice dynamical model

2013 ◽  
Vol 7 (1) ◽  
pp. 145-173 ◽  
Author(s):  
L. Zhao ◽  
L. Tian ◽  
T. Zwinger ◽  
R. Ding ◽  
J. Zong ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
21St Century ◽  
Climate Models ◽  
Average Rate ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Balance Model ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
The Impact

Abstract. We investigate the impact of climate change on a small Tibetan glacier that is representative of the tens of thousands of mountain glaciers in the region. We apply a three-dimensional, thermo-mechanically coupled full-Stokes model to Gurenhekou Glacier located in the southern Tibetan Plateau. The steep and rugged geometry requires use of such a flow model to simulate the dynamical evolution of the glacier. We parameterize the temperature and mass balance using nearby automatic weather stations and an energy balance model for another glacier in the same mountain range. Summer air temperature increased at 0.02 K a−1 over the past 50 yr, and the glacier has retreated at an average rate of 8.3 m a−1. Prognostic simulations suggest an accelerated retreating rate up to 14 m a−1 for the next 50 yr under continued steady warming, which is consistent with observed increased retreat in the last decade. However, regional climate models suggest a marked increase in warming rate over Tibet during the 21st century, and this rate causes about a 1% per year loss of glaciated area and glacier volume. These changes imply that this small glacier will probably disappear in a century. Although Tibetan glaciers are not particularly sensitive to climate warming, the rather high warming rates predicted by regional climate models combined with the small sizes of most Tibetan glaciers suggest that significant numbers of glaciers will be lost in the region during the 21st century.

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