scholarly journals Investigating the bias of TanDEM-X digital elevation models of glaciers on the Tibetan Plateau: impacting factors and potential effects on geodetic mass-balance measurements

2021 ◽  
pp. 1-14
Author(s):  
Jia Li ◽  
Zhi-Wei Li ◽  
Jun Hu ◽  
Li-Xin Wu ◽  
Xin Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Glacier Mass Balance ◽  
The Tibetan Plateau ◽  
Digital Elevation ◽  
Impacting Factors ◽  
Geodetic Mass Balance ◽  
Study Sites ◽  
West Kunlun ◽  
The Impact

Abstract The TanDEM-X DEM is a valuable data source for estimating glacier mass balance. However, the accuracy of TanDEM-X elevation over glaciers can be affected by microwave penetration and phase decorrelation. To investigate the bias of TanDEM-X DEMs of glaciers on the Tibetan Plateau, these DEMs were subtracted from SPOT-6 DEMs obtained around the same time at two study sites. The average bias over the studied glacier areas in West Kunlun (175.0 km2) was 2.106 ± 0.012 m in April 2014, and it was 1.523 ± 0.011 m in Geladandong (228.8 km2) in October 2013. By combining backscatter coefficients and interferometric coherence maps, we found surface decorrelation and baseline decorrelation can cause obvious bias in addition to microwave penetration. If the optical/laser data and winter TanDEM-X data were used as new and historic elevation sources for mass-balance measurements over an arbitrary observation period of 10 years, the glacier mass loss rates in West Kunlun and Geladandong would be potentially underestimated by 0.218 ± 0.016 and 0.158 ± 0.011 m w.e. a−1, respectively. The impact is therefore significant, and users should carefully treat the bias of TanDEM-X DEMs when retrieving a geodetic glacier mass balance.

Simulation and analysis of glacier runoff and mass balance in the Nam Co basin, southern Tibetan Plateau

2015 ◽  
Vol 61 (227) ◽  
pp. 447-460 ◽  
Author(s):  
Gao Tanguang ◽  
Kang Shichang ◽  
Lan Cuo ◽  
Zhang Tingjun ◽  
Zhang Guoshuai ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Water Balance ◽  
Mass Balance ◽  
Glacier Mass Balance ◽  
The Tibetan Plateau ◽  
Distributed Hydrological Model ◽  
Index Method ◽  
Glacier Melt ◽  
Glacier Runoff ◽  
Southern Tibetan Plateau

AbstractRunoff estimation in high-altitude glacierized basins is an important issue on the Tibetan Plateau. To investigate glacier mass balance, runoff and water balance in the Qugaqie basin and Zhadang sub-basin in the southern Tibetan Plateau, two glacier models and three snow models were integrated into the spatially distributed hydrological model JAMS/J2K. The results showed that the temperature index method simulated glacier runoff better than the degree-day factor method. The simulated glacier melt volume in the Qugaqie basin in 2006, 2007 and 2008 contributed 58%, 50% and 41%, respectively, to its total runoff. In the Zhadang basin, the glacier melt volume contributed 78% and 66% to its runoff during 2007 and 2008, respectively. Compared with the observation results, the simulated glacier mass balance showed similar variations with slightly higher values, indicating an underestimation of glacier melt volume. The water balance simulation in the upstream areas (705–874 mm) was comparable to that in the downstream areas (1051–1502 mm) and generally lower than the observed results. In both basins, the glacier mass-balance simulation was relatively accurate in the melt season compared to the other seasons.

scholarly journals Sensitivity of geodetic glacier mass balance estimation to DEM void interpolation

2018 ◽  
Author(s):  
Robert McNabb ◽  
Christopher Nuth ◽  
Andreas Kääb ◽  
Luc Girod
Keyword(s):  
Mass Balance ◽  
Terrestrial Ecosystems ◽  
Glacier Mass Balance ◽  
Direct Impact ◽  
Glacier Surface ◽  
Southeast Alaska ◽  
Digital Elevation ◽  
Regional Basis ◽  
The Impact

Abstract. Glacier mass balance is a direct expression of climate change, with implications for sea level, ocean chemistry, oceanic and terrestrial ecosystems, and water resources. Traditionally, glacier mass balance has been estimated using in-situ measurements of changes in surface height and density at select locations on the glacier surface, or by comparing changes in surface height using repeat, full-coverage digital elevation models (DEMs), also called the geodetic method. DEMs often have gaps in coverage (voids) based on the nature of the sensor used and the surface being measured. The way that these voids are accounted for has a direct impact on the estimate of geodetic glacier mass balance, though a systematic comparison of different proposed methods has been heretofore lacking. In this study, we determine the impact and sensitivity of void-filling methods on estimates of volume change. Using two spatially complete, high-resolution DEMs over Southeast Alaska, USA, we compare 11 different void-filling methods on a glacier-by-glacier and regional basis. We find that a few methods introduce biases of up to 20 % in the regional results, while other methods give results very close (

scholarly journals Mass balance of Xiao Dongkemadi glacier on the central Tibetan Plateau from 1989 to 1995

2000 ◽  
Vol 31 ◽  
pp. 159-163 ◽  
Author(s):  
Koji Fujita ◽  
Yutaka Ageta ◽  
Pu Jianchen ◽  
Yao Tandong
Keyword(s):  
Body Temperature ◽  
Tibetan Plateau ◽  
Mass Balance ◽  
Air Temperature ◽  
Black Body ◽  
Glacier Mass Balance ◽  
The Tibetan Plateau ◽  
Central Tibetan Plateau ◽  
Geostationary Meteorological Satellite ◽  
Continuous Mass

AbstractData on the mass balance of Xiao Dongkemadi glacier in the Tanggula mountains, central Tibetan Plateau, were obtained over 5 5 years from 1989 to 1995. These are the first continuous mass-balance data for a continental-type glacier on the Tibetan Plateau, where the glacier accumulates during the summer monsoon (summer-accumulation-type glacier). Mass-balance vs altitude profiles were steeper in the negative than in the positive mass-balance years. This is considered to have resulted from the effect of summer accumulation. The annual mass balance is compared with air temperature, precipitation, and black-body temperature in the area including the glacier, which is calculated from infrared radiation observations by theJapanese Geostationary Meteorological Satellite. It was found that the interannual variation in the glacier mass balance was not closely related to maximum monthly mean air temperature, while it did have a relatively good correlation with maximum monthly mean black-body temperature.

scholarly journals Superimposed ice in glacier mass balance on the Tibetan Plateau

1996 ◽  
Vol 42 (142) ◽  
pp. 454-460 ◽  
Author(s):  
Koji Fujita ◽  
Katsumoto Seko ◽  
Yutaka Ageta ◽  
Pu Jianchen ◽  
Yao Tandong
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Ice Formation ◽  
Glacier Mass Balance ◽  
The Tibetan Plateau ◽  
Snow Layer ◽  
Glacier Surface ◽  
Accumulation Zone ◽  
Central Tibetan Plateau ◽  
Glacier Ice

AbstractThe relations between mass balance and meltwater refreezing were examined on the basis of glaciological observations carried out in summer 1993 on Xiao Dongkemadi Glacier, Tanggula Mountains, central Tibetan Plateau. On this glacier, a part of meltwaler refreezes at the snow/ice interface as superimposed ice. The amount of superimposed ice formation was determined by both meltwater supply and temperature condition of the glacier. Snow-layer thickness on the glacier ice body is less than 2 m, even in the higher accumulation zone. About 60% of meltwaler generated in the accumulation zone for the period May–September was trapped at the snow/ice interface by refreezing, and was not discharged out of the glacier. About 26% of accumulated snow to the glacier surface was replaced on the snow/ice interface by refreezing in the accumulation zone. These facts indicate that superimposed ice formation is quite significant for water retention in glaciers under low-precipitation conditions.

scholarly journals Effect of summer accumulation on glacier mass balance on the Tibetan Plateau revealed by mass-balance model

2000 ◽  
Vol 46 (153) ◽  
pp. 244-252 ◽  
Author(s):  
Koji Fujita ◽  
Yutaka Ageta
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Surface Albedo ◽  
Arid Environment ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
The Tibetan Plateau ◽  
Central Plateau ◽  
Model Calculations ◽  
Surface Mass

AbstractThe characteristics and sensitivities of a cold-based glacier on the Tibetan Plateau, where the summer monsoon provides most of the mass input to glaciers, are discussed using an energy-balance model incorporating the process of water refreezing. The model accurately represents the observational results related to the mass balance of Xiao Dongkemadi glacier on the central plateau during 1992/93. Our data revealed that the mass balance of cold glaciers cannot simply be described by the surface mass/heat balances, because about 20% of infiltrated water is refrozen and thus does not run off from the glacier. Model calculations demonstrate that glaciers in an arid environment can maintain their mass since the monsoon provides precipitation during the melting season. Snowfall in summer keeps surface albedo high and largely restrains ablation. Nevertheless, the calculations also make clear that glaciers on the plateau are more vulnerable than those of other regions because of summer accumulation. In the monsoon climate, warming would cause not only a decrease in accumulation, but also a drastic increase in ablation in combination with surface-albedo lowering. Therefore, although glaciers on and around the plateau can be sustained by summer accumulation, they are more vulnerable to warming than winter-accumulation-type glaciers.

scholarly journals Sensitivity of glacier volume change estimation to DEM void interpolation

2019 ◽  
Vol 13 (3) ◽  
pp. 895-910 ◽  
Author(s):  
Robert McNabb ◽  
Christopher Nuth ◽  
Andreas Kääb ◽  
Luc Girod
Keyword(s):  
Mass Balance ◽  
Volume Change ◽  
Thermal Emission ◽  
Glacier Mass Balance ◽  
Southeast Alaska ◽  
Interpolation Methods ◽  
Digital Elevation ◽  
Regional Basis ◽  
The Impact ◽  
Voided Volume

Abstract. Glacier mass balance has been estimated on individual glacier and regional scales using repeat digital elevation models (DEMs). DEMs often have gaps in coverage (“voids”), the properties of which depend on the nature of the sensor used and the surface being measured. The way that these voids are accounted for has a direct impact on the estimate of geodetic glacier mass balance, though a systematic comparison of different proposed methods has been heretofore lacking. In this study, we determine the impact and sensitivity of void interpolation methods on estimates of volume change. Using two spatially complete, high-resolution DEMs over southeast Alaska, USA, we artificially generate voids in one of the DEMs using correlation values derived from photogrammetric processing of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes. We then compare 11 different void interpolation methods on a glacier-by-glacier and regional basis. We find that a few methods introduce biases of up to 20 % in the regional results, while other methods give results very close (<1 % difference) to the true, non-voided volume change estimates. By comparing results from a few of the best-performing methods, an estimate of the uncertainty introduced by interpolating voids can be obtained. Finally, by increasing the number of voids, we show that with these best-performing methods, reliable estimates of glacier-wide volume change can be obtained, even with sparse DEM coverage.

scholarly journals A Surging Glacier Recognized by Remote Sensing on the Zangser Kangri Ice Field, Central Tibetan Plateau

2021 ◽  
Vol 13 (6) ◽  
pp. 1220
Author(s):  
Bowen Jia ◽  
Shugui Hou ◽  
Yetang Wang
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Thermal Emission ◽  
Surface Velocity ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Landsat 8 ◽  
The Tibetan Plateau ◽  
Landsat Images ◽  
Ice Field

A glacier surge, which is quasi-periodic and involves rapid flow, is an abnormal glacier motion. Although some glaciers have been found to be surging, little is known about surging glaciers on the Tibetan Plateau (TP), especially the Central and Northern TP. Here, we found a surging glacier (GLIMS ID: G085885E34389N) on the Zangser Kangri ice field (ZK), Central TP, by means of the digital elevation models (DEMs) from the Shuttle Radar Topography Mission (SRTM), TanDEM-X 90 m, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEMs, and High Mountain Asia 8-m DEM (HMA), combined with Landsat images and the Global Land Ice Velocity Extraction from Landsat 8 (GoLIVE) dataset. This surge event was confirmed by the crevasses, shear margin, and visible advancing snout shown in the Landsat images produced since 2014 and the HMA. The inter-comparison of these DEMs and the surface velocity changes showed that the surge event started between October 2012 and January 2014. The glacier may have also surged in the 1970s, based on a comparison between the topographical map and Landsat images. The glacier mass balance here has been slightly positive from 1999 onward (+0.03 ± 0.06 m w.e.a−1 from 1999 to 2015, +0.02 ± 0.07 m w.e.a−1 from 1999 to December 2011), which may indicate that the ZK is located on the southern edge of the mass balance anomaly on the TP. Combining with other surging glaciers on the Central and Northern TP, the relatively balanced mass condition, large size, and shallow slope can be associated with glacier surges on the Central and Northern TP.

scholarly journals Modelled mass balance of Xibu glacier, Tibetan Plateau: sensitivity to climate change

2010 ◽  
Vol 56 (196) ◽  
pp. 235-248 ◽  
Author(s):  
Caidong Caidong ◽  
Asgeir Sorteberg
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Warming Trend ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
Equilibrium Line Altitude ◽  
Glacier Terminus

AbstractDue to a lack of in situ measurements, model-based studies of glacier mass balance in the Tibetan Plateau are very limited. An energy-balance model is applied to analyse the mass-balance sensitivity of Xibu glacier, in the Nyainqêntanglha mountain range, to climatic change. A sensitivity calculation shows that a temperature change of ±1°C or a precipitation change of ±35% changes the equilibrium-line altitude (ELA) by 140 ± 125 m. We use a clustering method to link local weather parameters, including wet-season temperatures, to weather types observed over the period 1955–2006. Modelled variability of the Xibu glacier mass balance seems to be controlled by air-temperature variations during the wet season (May–September) and by a long-term warming trend that is unrelated to weather type. The observed wet-season temperature trend of 0.23°C (10 a)−1 leads to an estimated lengthening of the ablation season by 8 days at the glacier terminus (5000 m a.s.l.) and by 23 days at the ELA (5590 m a.s.l.) over the period 1966–2005. The calculated rise in the ELA was 49 m (10 a)−1.

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