scholarly journals A glacier inventory for the western Nyainqentanglha Range and the Nam Co Basin, Tibet, and glacier changes 1976–2009

2010 ◽  
Vol 4 (3) ◽  
pp. 419-433 ◽  
Author(s):  
T. Bolch ◽  
T. Yao ◽  
S. Kang ◽  
M. F. Buchroithner ◽  
D. Scherer ◽  
...  
Keyword(s):  
Drainage Basin ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Change Analysis ◽  
Glacier Inventory ◽  
Manual Adjustment ◽  
Main Driver ◽  
Climate Interactions ◽  
Lake Nam Co

Abstract. The western Nyainqentanglha Range is located in the south-eastern centre of the Tibetan Plateau. Its north-western slopes drain into Lake Nam Co. The region is of special interest for glacio-climatological research as it is influenced by both the continental climate of Central Asia and the Indian Monsoon system, and situated at the transition zone between temperate and subcontinental glaciers. A glacier inventory for the whole mountain range was generated for the year around 2001 using automated remote sensing and GIS techniques based on Landsat ETM+ and SRTM3 DEM data. Glacier change analysis was based on data from Hexagon KH-9 and Landsat MSS (both 1976), Metric Camera (1984), and Landsat TM/ETM+ (1991, 2001, 2005, 2009). Manual adjustment was especially necessary for delineating the debris-covered glaciers and the glaciers on the panchromatic Hexagon data. In the years around 2001 the whole mountain range contained about 960 glaciers covering an area of 795.6 ± 22.3 km2 while the ice in the drainage basin of Nam Co covered 198.1 ± 5.6 km2. The median elevation of the glaciers was about 5800 m with the majority terminating around 5600 m. Five glaciers with debris-covered tongues terminated lower than 5200 m. The glacier area decreased by −6.1 ± 3% between 1976 and 2001. This is less than reported in previous studies based on the 1970s topographic maps and Landsat data from 2000. Glaciers continued to shrink during the period 2001–2009. No advancing glaciers were detected. Detailed length measurements for five glaciers indicated a retreat of around 10 m per year (1976–2009). Ice cover is higher south-east of the mountain ridge which reflects the windward direction to the monsoon. The temperature increase during the ablation period was probably the main driver of glacier wastage, but the complex glacier-climate interactions need further investigation.

scholarly journals A glacier inventory for the western Nyainqentanglha Range and Nam Co Basin, Tibet, and glacier changes 1976–2009

2010 ◽  
Vol 4 (2) ◽  
pp. 429-467 ◽  
Author(s):  
T. Bolch ◽  
T. Yao ◽  
S. Kang ◽  
M. F. Buchroithner ◽  
D. Scherer ◽  
...  
Keyword(s):  
Drainage Basin ◽  
Western Slope ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Change Analysis ◽  
Glacier Inventory ◽  
Manual Adjustment ◽  
Lake Nam Co ◽  
Year 2000

Abstract. The western Nyainqentanglha Mountain Range is located in the south-eastern centre of the Tibetan Plateau. Its north-western slope drains into Lake Nam Co. The area is of special interest for glacio-climatological research as this region is influenced by both the continental climate of Central Asia and the Indian Monsoon system, and it is situated at the transition zone between temperate and subcontinental glaciers. A glacier inventory for the whole mountain range was generated for the year ~2000 using automated remote sensing and GIS techniques based on Landsat ETM+ and SRTM3 DEM data. The change analysis is based on data from Hexagon KH-9 and Landsat MSS (year 1976), Metric Camera (year 1984), and Landsat TM/ETM+ (1991, 2001, 2005, 2009). Manual adjustment was especially necessary for the panchromatic Hexagon data and for debris-covered glaciers. The whole mountain range contains about 960 glaciers covering an area of 795.6 ± 22.3 km2 while the ice in the drainage basin of Nam Co covers 198.1 ± 5.6 km2. The median elevation of the glaciers is ~5800 m a with the majority terminating around 5600 m. Five glaciers with debris-covered tongues terminate lower than 5200 m. The glacier area decreased between 1976 and 2001 by about 6 ± 3%, which is less than presented in previous studies based on topographic maps from the 1970s and Landsat data from 2000. Glaciers continued to shrink during the period 2001–2009. No advancing glaciers were detected. Detailed length measurements for five glaciers indicate a retreat of the tongues of around 10 m per year (1976–2009) with higher absolute but lower relative values for the larger glaciers.

scholarly journals Reviews and syntheses: How do abiotic and biotic processes respond to climatic variations at the Nam Co catchment (Tibetan Plateau)?

2019 ◽  
Author(s):  
Sten Anslan ◽  
Mina Azizi Rad ◽  
Johannes Buckel ◽  
Paula Echeverria Galindo ◽  
Jinlei Kai ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Air Temperature ◽  
Water Availability ◽  
Global Climate ◽  
Livestock Grazing ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Climatic Fluctuations ◽  
Climatic Oscillations ◽  
Lake Nam Co

Abstract. The Tibetan Plateau (TP) is the largest alpine plateau on Earth and plays an important role in global climate dynamics. On the TP, climate change is happening particularly fast, with an increase in air temperature twice the global average. The particular sensitivity of this high mountainous environment allows the observation and tracking of abiotic and biotic feedback mechanisms. Closed lake systems, such as the Nam Co on the central TP represent important natural laboratories for tracking past and recent climatic oscillations, as well as geobiological processes and interactions within their respective catchments. This review gives an interdisciplinary overview of modern and paleoenvironmental changes, focusing on Nam Co as model system. In the catchment area, the steep rise in air temperature forced glaciers to melt, leading to a rise in lake levels and changes in water chemistry. Some studies base their conclusions on inconsistent glacier inventories but an ever-increasing deglaciation and thus higher water availability have persisted over the last decades. The enhanced water availability causes translocation of sediments, nutrients and dissolved organic matter to the lake, as well as higher carbon emissions to the atmosphere. The intensity of grazing has a significant effect on CO2 fluxes, with moderate grazing enhancing belowground allocation of carbon while adversely affecting the C-sink potential through reduction of above- and subsurface biomass at higher grazing intensities. Furthermore, increasing pressure from human activities and livestock grazing are enhancing grassland degradation processes, thus shaping biodiversity patterns in the lake and catchment. The environmental signal provided by taxon-specific analysis (e.g. diatoms and ostracods) in Nam Co have revealed profound climatic fluctuations between warmer/cooler and wetter/drier periods since the late Pleistocene and an increasing input of freshwater and nutrients from the catchment in recent years. Based on the reviewed literature, we outline perspectives to further understand the effects of global warming on geo- and biodiversity and their interplay in the Lake Nam Co, which acts as a case study for potentially TP-wide processes that are currently shaping the earth’s future.

What is driving India-Asia convergence?

2021 ◽  
Author(s):  
Santanu Bose ◽  
Wouter P Schellart ◽  
Vincent Strak ◽  
João C. Duarte ◽  
Zhihao Chen
Keyword(s):  
Subduction Zones ◽  
Boundary Migration ◽  
Physical Models ◽  
Plate Motion ◽  
Indian Plate ◽  
Mountain Range ◽  
Complete Disappearance ◽  
The Tibetan Plateau ◽  
Main Driver ◽  
The Himalaya

<p>The Himalaya and the Tibetan plateau, the highest mountain range on Earth, have been growing continuously for the last 55 Myrs since India collided with Eurasia. The forces driving this protracted mountain building process are still not fully understood, and continue to puzzle Earth Scientists. Although it is now well accepted that subduction zones are the main driver for plate motion, plate boundary migration, and mantle flow in the asthenosphere, their role in driving Indian indentation into the Asian landmass has never been tested with geodynamic models. This study uses four-dimensional geodynamic physical models to test the role of lateral subduction zones in driving the India-Asia collision. The objective of our study is to investigate if the slab pull force of the Sunda and Makran slabs have any role to play in the dynamics of the ongoing India-Asia convergence, particularly after the complete disappearance of the Tethyan slab, which was primarily steering the northward travel of the Indian plate since late Jurassic. To address this issue, we performed three experiments by varying the size and configuration of the subducting plate in the initial model setup.  Our experimental results show that active subduction of the Indo-Australian plate along the Sunda subduction zone is the main driver of the India-Asia convergence, Indian indentation, the growth of the Himalaya-Tibet mountains, and the eastward extrusion of southeast Asia. Our work further suggests that the protracted growth of collisional mountains on Earth requires nearby active subduction zones and, therefore, Himalayan-type orogens may have been rare in the Earth’s history.</p>

scholarly journals Summertime thermally-induced circulations over the Lake Nam Co region of the Tibetan Plateau

2015 ◽  
Vol 29 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Xianyu Yang ◽  
Yaqiong Lü ◽  
Yaoming Ma ◽  
Jun Wen
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Thermally Induced ◽  
Lake Nam Co

scholarly journals Glacier variations in the Himalaya from 1990 to 2015 based on remote sensing

2020 ◽  
Author(s):  
Qin Ji ◽  
Jun Dong ◽  
Hong-rong Li ◽  
Yan Qin ◽  
Rui Liu ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Large Area ◽  
Glacier Inventory ◽  
The North ◽  
South Slope ◽  
Monsoon System ◽  
The Himalaya ◽  
Continental Climate

Abstract. The Himalaya is located in the southwest margin of the Tibetan Plateau. The region is of special interest for glacio-climatological research as it is influenced by both the continental climate of Central Asia and The Indian Monsoon system. Despite its large area covered by glaciers, detail glacier inventory data are not yet available for the entire Himalaya. The study presents spatial patterns in glacier area in the entire Himalaya are multiple spatial scales. We combined Landsat TM/ETM+/OLI from 1990 to 2015 and ASTER GEDM (30 m). In the years around 1990 the whole mountain range contained about 12211 glaciers covering an area of 23229.27 km2, while the ice on south slope covered 14451.25 km2. Glaciers are mainly distributed in the western of the Himalaya with an area of 11551.69 km2 and the minimum is the eastern. The elevation of glacier mainly distributed at 4,800∼6,200 m a.s.l. with an area percent of approximately 84 % in 1990. The largest number and ice cover of glaciers is hanging glacier and valley glacier, respectively. The number of debris-covered glaciers is relatively small, whereas covers an area of about 44.21 % in 1990. The glacier decreased by 10.99 % and this recession has accelerated from 1990 to 2015. The average annual shrinkage rate of the glaciers on the north slope (0.54 % a−1) is greater than that on the south slope (0.38 % a−1). Glacier decreased in the debris-covered glaciers and debris-free glaciers, and the area loss for the first is about 15.56 % and 5.22 % for the latter during 1990–2015, which showed that the moraine in the Himalaya can inhibit the ablation of glaciers to some extent.

scholarly journals Using Landscape Change Analysis and Stakeholder Perspective to Identify Driving Forces of Human–Wildlife Interactions

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 146
Author(s):  
Mihai Mustățea ◽  
Ileana Pătru-Stupariu
Keyword(s):  
Landscape Change ◽  
Ursus Arctos ◽  
Driving Forces ◽  
Brown Bear ◽  
Mountain Range ◽  
Change Analysis ◽  
Local Stakeholders ◽  
Stakeholder Perspective ◽  
Forested Ecosystems ◽  
Forest Habitats

Human–wildlife interactions (HWI) were frequent in the post-socialist period in the mountain range of Central European countries where forest habitats suffered transitions into built-up areas. Such is the case of the Upper Prahova Valley from Romania. In our study, we hypothesized that the increasing number of HWI after 1990 could be a potential consequence of woodland loss. The goal of our study was to analyse the effects of landscape changes on HWI. The study consists of the next steps: (i) applying 450 questionnaires to local stakeholders (both citizens and tourists) in order to collect data regarding HWI temporal occurrences and potential triggering factors; (ii) investigating the relation between the two variables through the Canonical Correspondence Analysis (CCA); (iii) modelling the landscape spatial changes between 1990 and 2018 for identifying areas with forest loss; (iv) overlapping the distribution of both the households affected by HWI and areas with loss of forested ecosystems. The local stakeholders indicate that the problematic species are the brown bear (Ursus arctos), the wild boar (Sus scrofa), the red fox (Vulpes vulpes) and the grey wolf (Canis lupus). The number of animal–human interactions recorded an upward trend between 1990 and 2018, and the most significant driving factors were the regulation of hunting practices, the loss of habitats, and artificial feeding. The landscape change analysis reveals that between 1990 and 2018, the forest habitats were replaced by built-up areas primarily on the outskirts of settlements, these areas coinciding with frequent HWI. The results are valid for both forest ecosystems conservation in the region, wildlife management, and human infrastructures durable spatial planning.

scholarly journals Surface ozone at Nam Co (4730 m a.s.l.) in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

2017 ◽  
Author(s):  
Xiufeng Yin ◽  
Shichang Kang ◽  
Benjamin de Foy ◽  
Zhiyuan Cong ◽  
Jiali Luo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Surface Ozone ◽  
Early Morning ◽  
Photochemical Reactions ◽  
Transport Processes ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Mixing Ratios ◽  
Northern Tibetan Plateau ◽  
Ozone Levels

Abstract. Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present long-term measurements for ~ 5 years (January 2011 to October 2015) of surface ozone mixing ratios at Nam Co Station, which is a regional background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions and potential local vertical mixing. Model results indicate that the study site is affected by the surrounding areas in different seasons and that air masses from the northern Tibetan Plateau lead to increased ozone levels in the summer. In contrast to the surface ozone levels at the edges of the Tibetan Plateau, those at Nam Co Station are less affected by stratospheric intrusions and human activities which makes Nam Co Station representative of vast background areas in the central Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites in the Tibetan Plateau and beyond, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a reference for model simulations in the future.

scholarly journals Atmospheric brown clouds reach the Tibetan Plateau by crossing the Himalayas

2015 ◽  
Vol 15 (11) ◽  
pp. 6007-6021 ◽  
Author(s):  
Z. L. Lüthi ◽  
B. Škerlak ◽  
S.-W. Kim ◽  
A. Lauer ◽  
A. Mues ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Weather Prediction ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Pollution Transport ◽  
Synoptic Scale ◽  
Gangetic Plain ◽  
Dark Light ◽  
Air Masses ◽  
Pollution Episode

Abstract. The Himalayas and the Tibetan Plateau region (HTP), despite being a remote and sparsely populated area, is regularly exposed to polluted air masses with significant amounts of aerosols including black carbon. These dark, light-absorbing particles are known to exert a great melting potential on mountain cryospheric reservoirs through albedo reduction and radiative forcing. This study combines ground-based and satellite remote sensing data to identify a severe aerosol pollution episode observed simultaneously in central Tibet and on the southern side of the Himalayas during 13–19 March 2009 (pre-monsoon). Trajectory calculations based on the high-resolution numerical weather prediction model COSMO are used to locate the source regions and study the mechanisms of pollution transport in the complex topography of the HTP. We detail how polluted air masses from an atmospheric brown cloud (ABC) over South Asia reach the Tibetan Plateau within a few days. Lifting and advection of polluted air masses over the great mountain range is enabled by a combination of synoptic-scale and local meteorological processes. During the days prior to the event, winds over the Indo-Gangetic Plain (IGP) are generally weak at lower levels, allowing for accumulation of pollutants and thus the formation of ABCs. The subsequent passing of synoptic-scale troughs leads to southwesterly flow in the middle troposphere over northern and central India, carrying the polluted air masses across the Himalayas. As the IGP is known to be a hotspot of ABCs, the cross-Himalayan transport of polluted air masses may have serious implications for the cryosphere in the HTP and impact climate on regional to global scales. Since the current study focuses on one particularly strong pollution episode, quantifying the frequency and magnitude of similar events in a climatological study is required to assess the total impact.

scholarly journals Use of Wyoming Southern Bighorn Mountains Topographic Map Evidence to Test a Recently Proposed Regional Geomorphology Paradigm: USA

2019 ◽  
Vol 11 (3) ◽  
pp. 1
Author(s):  
Eric Clausen
Keyword(s):  
Drainage Basin ◽  
Water Source ◽  
High Elevation ◽  
Mountain Range ◽  
Topographic Map ◽  
The South ◽  
New Paradigm ◽  
River Drainage ◽  
North Fork ◽  
Bighorn Mountains

Detailed topographic maps covering a high elevation Bighorn-Powder River drainage divide segment in the southern Bighorn Mountains are used to test a recently proposed regional geomorphology paradigm. Fundamentally different from the commonly accepted paradigm the new paradigm predicts immense south-oriented continental ice sheet melt water floods once flowed across what is now the entire Missouri River drainage basin, in which the high Bighorn Mountains are located. Such a possibility is incompatible with commonly accepted paradigm expectations and previous investigators have interpreted Bighorn Mountains geomorphic history quite differently. The paradigm test began in the high glaciated Bighorn Mountains core area where numerous passes, or divide crossings, indicate multiple and sometimes closely spaced streams of water once flowed across what is now the Bighorn-Powder River drainage divide. To the south of the glaciated area, but still in a Precambrian bedrock region, the test found the roughly adjacent and parallel south-oriented North Fork Powder River and Canyon Creek headwaters located on opposite sides of the Bighorn-Powder River drainage divide with North Fork Powder River headwaters closely linked to a 300-meter deep pass through which south-oriented water had probably flowed. Shallower divide crossings located further to the south suggest diverging and converging streams of water once flowed not only across the Bighorn-Powder River drainage divide, but also across Powder River and Bighorn River tributary drainage divides. The paradigm test also found published geologic maps and reports showing the presence of possible flood transported and deposited alluvium. While unable to determine the water source, the new paradigm test did find evidence that large south-oriented floods had crossed what was probably a rising Bighorn Mountains mountain range.

scholarly journals Erosion assessment in the middle Kali Gandaki (Nepal): A sediment budget approach

2013 ◽  
Vol 46 ◽  
Author(s):  
Monique Fort ◽  
Etienne Cossart
Keyword(s):  
Drainage Basin ◽  
Sediment Budget ◽  
Mountain Range ◽  
Primary Concern ◽  
Stream Power ◽  
Sediment Budgets ◽  
Relative Chronology ◽  
Wide Range ◽  
History Of

Active mountains supply the largest sediment fluxes experienced on earth. At mountain range scale, remote sensing approaches, sediments provenance or stream power law analyses, collectively provide rough long-term estimates of total erosion. Erosion is indeed controlled by rock uplift and climate, hence by a wide range of processes (detachment, transport and deposition), all operating within drainage basin units, yet with time and spatial patterns that are quite complex at local scale. We focus on the Kali Gandaki valley, along the gorge section across the Higher Himalaya (e.g. from Kagbeni down to Tatopani). Along this reach, we identify sediment sources, stores and sinks, and consider hillslope int eractions with valley floor, in particular valley damming at short and longer time scales, and their impact on sediment budgets and fluxes. A detailed sediment budget is presented, constrained by available dates and/or relative chronology, ranging from several 10 kyr to a few decades. Obtained results span over two orders of magnitude that can best be explained by the type and magnitude of erosional processes involved. We show that if large landslides contribute significantly to the denudation history of active mountain range, more frequent medium to small scales landslides are in fact of primary concern for Himalayan population.

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