scholarly journals Spatiotemporal dynamic characteristics of typical temperate glaciers in China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wang Shijin ◽  
Che Yanjun ◽  
Wei Yanqiang

AbstractChina’s temperate glaciers have a relatively warm and humid climate and hydrothermal conditions at low latitudes. Temperate glaciers, however, have larger ablation, higher ice temperatures, relatively fast movement speeds, and a significant sliding process at the bottom. As a result, these glaciers are more significantly affected by climate change. On the basis of topographic maps, aerial photography, and Landsat OLI images, and combined with existing research results, this paper systematically analyzed the temporal and spatial dynamic characteristics of typical temperate glaciers. The results are as follows: (1) From the 1950s to the 1970s, compared with other types of glaciers, temperate glaciers showed strong retreat and ablation trends in terms of area, length, speed, and mass balance. (2) The reduction rates of glacier areas of Kangri Garpo, Dagu Snow Mountain, Yulong Snow Mountain (YSM), and Meili Snow Mountain (MSM) in China’s temperate glacier areas all exceeded 38%, which was far above the national average of 18% from the 1950s to the 2010s. (3) The recent length retreat rates of Azha Glacier, Kangri Garpo, and Mingyong Glacier, MSM, Hailuogou Glacier (HG), Gongga Snow Mountain (GSM), and Baishui River Glacier No. 1 (BRGN1), YSM were above 22 m/a, which was faster than the retreat rates of other regions. (4) Consistent with glacier retreat, temperate glaciers also had a faster ice flow speed. The ice flow velocities of the BGN1, HG, Parlung River Glaciers No. 4 and 94, and Nyainqêntanglha were, respectively, 6.33–30.78 m/a, 41–205 m/a, 15.1–86.3 m/a, and 7.5–18.4 m/a, which was much faster than the velocity of other types of glaciers. (5) Mass loss of temperate glaciers was most dramatic during the observation period (1959–2015). The annual mass balance from eight typical temperate glaciers fluctuated between − 2.48 and 0.44 m w.e., and the annual average change rate of mass balance (− 0.037 m w.e./a) was much higher than that in China (− 0.015 m w.e./a, p < 0.0001) and globally (− 0.013 m w.e./a, p < 0.0001).

2010 ◽  
Vol 22 (1) ◽  
pp. 10-22 ◽  
Author(s):  
Mingxing Xu ◽  
Ming Yan ◽  
Jiawen Ren ◽  
Songtao Ai ◽  
Jiancheng Kang ◽  
...  

2010 ◽  
Vol 4 (1) ◽  
pp. 115-128 ◽  
Author(s):  
R. J. Thayyen ◽  
J. T. Gergan

Abstract. A large number of Himalayan glacier catchments are under the influence of humid climate with snowfall in winter (November–April) and south-west monsoon in summer (June–September) dominating the regional hydrology. Such catchments are defined as "Himalayan catchment", where the glacier meltwater contributes to the river flow during the period of annual high flows produced by the monsoon. The winter snow dominated Alpine catchments of the Kashmir and Karakoram region and cold-arid regions of the Ladakh mountain range are the other major glacio-hydrological regimes identified in the region. Factors influencing the river flow variations in a "Himalayan catchment" were studied in a micro-scale glacier catchment in the Garhwal Himalaya, covering an area of 77.8 km2. Three hydrometric stations were established at different altitudes along the Din Gad stream and discharge was monitored during the summer ablation period from 1998 to 2004, with an exception in 2002. These data have been analysed along with winter/summer precipitation, temperature and mass balance data of the Dokriani glacier to study the role of glacier and precipitation in determining runoff variations along the stream continuum from the glacier snout to 2360 m a.s.l. The study shows that the inter-annual runoff variation in a "Himalayan catchment" is linked with precipitation rather than mass balance changes of the glacier. This study also indicates that the warming induced an initial increase of glacier runoff and subsequent decline as suggested by the IPCC (2007) is restricted to the glacier degradation-derived component in a precipitation dominant Himalayan catchment and cannot be translated as river flow response. The preliminary assessment suggests that the "Himalayan catchment" could experience higher river flows and positive glacier mass balance regime together in association with strong monsoon. The important role of glaciers in this precipitation dominant system is to augment stream runoff during the years of low summer discharge. This paper intends to highlight the importance of creating credible knowledge on the Himalayan cryospheric processes to develop a more representative global view on river flow response to cryospheric changes and locally sustainable water resources management strategies.


2016 ◽  
Vol 57 (71) ◽  
pp. 289-294 ◽  
Author(s):  
Phuntsho Tshering ◽  
Koji Fujita

AbstractThis study presents the first decadal mass-balance record of a small debris-free glacier in the Bhutan Himalaya, where few in situ measurements have been reported to date. Since 2003 we have measured the mass balance of Gangju La glacier, which covers an area of 0.3km2 and extends from 4900 to 5200ma.s.l., using both differential GPS surveys (geodetic method) and stake measurements (direct method). The observed mass balance ranged from –1.12 to –2.04mw.e. a–1 between 2003 and 2014. The glacier exhibited much greater mass loss than neighbouring glaciers in the eastern Himalaya and southeastern Tibet, which are expected to be sensitive to climate change due to the monsooninfluenced humid climate. Observed mass-balance profiles suggest that the equilibrium-line altitude has been higher than Gangju La glacier since 2003, implying that the entire glacier has experienced net ablation for at least the past decade.


2004 ◽  
Vol 39 ◽  
pp. 557-562 ◽  
Author(s):  
Pedro Skvarca ◽  
Hernán De Angelis ◽  
Andrés F. Zakrajsek

AbstractFollowing the collapse of Larsen A in 1995, about 3200 km2 of Larsen B ice shelf disintegrated in early 2002 during the warmest summer recorded on the northeastern Antarctic Peninsula. Immediately prior to disintegration the last field campaign was carried out on Larsen B. Measurements included surface net mass balance, velocity and strain rate on a longitudinal transect along Crane Glacier flowline and over a remnant section confined within Seal Nunataks that survived the collapse. In addition, an automatic weather station located nearby allowed derivation of melt days relevant to the formation and extent of surface meltwater. Repeated surveys allowed us to detect a significant acceleration in ice-flow velocity and associated increasing strain rates along the longitudinal transect. It may be possible to use this acceleration as a predictor of imminent ice-shelf collapse, applicable to ice shelves subject to similar climatic conditions. Additional information on recent ongoing changes was provided by a visible satellite image acquired in early 2003.


2021 ◽  
Author(s):  
Jan De Rydt ◽  
Ronja Reese ◽  
Fernando Paolo ◽  
G Hilmar Gudmundsson

&lt;p&gt;Pine Island Glacier in West Antarctica is among the fastest changing glaciers worldwide. Much of its fast-flowing central trunk is thinning and accelerating, a process thought to have been triggered by ocean-induced changes in ice-shelf buttressing. The measured acceleration in response to perturbations in ice thickness is a non-trivial manifestation of several poorly-understood physical processes, including the transmission of stresses between the ice and underlying bed. To enable robust projections of future ice flow, it is imperative that numerical models include an accurate representation of these processes. Here we combine the latest data with analytical and numerical solutions of SSA ice flow to show that the recent increase in flow speed of Pine Island Glacier is only compatible with observed patterns of thinning if a spatially distributed, predominantly plastic bed underlies large parts of the central glacier and its upstream tributaries.&lt;/p&gt;


1992 ◽  
Vol 38 (129) ◽  
pp. 223-232 ◽  
Author(s):  
J. Oerlemans

AbstractThree glaciers in southern Norway, with very different mass-balance characteristics, are studied with an energy-balance model of the ice/snow surface. The model simulates the observed mass-balance profiles in a satisfactory way, and can thus be used with some confidence in a study of climate sensitivity. Calculated changes in equilibrium-line altitude for a 1 K temperature increase are 110, 108 and 135 m for Nigardsbreen, Hellstugubreen and Alfotbreen, respectively. The corresponding changes in mass balance, averaged over the entire glacier area, are −0.88, −0.715 and −1.11 m year−1 (water equivalent).Runs with an ice-flow model for Nigardsbreen, to which calculated mass-balance profiles arc imposed, predict that the front will advance by 3 km for a 1 K cooling, and will retreat by as much as 6.5 km for a 1 K warming. The response to a 10% increase in precipitation would be a 2 km advance of the snout, whereas a 4 km retreat is predicted for a 10% decrease. This large sensitivity (as compared to many other glaciers) is to a large extent due to the geometry of Nigardsbreen.


2016 ◽  
Vol 57 (73) ◽  
pp. 25-38 ◽  
Author(s):  
Timothy C. Bartholomaus ◽  
Leigh A. Stearns ◽  
David A. Sutherland ◽  
Emily L. Shroyer ◽  
Jonathan D. Nash ◽  
...  

ABSTRACTNeighboring tidewater glaciers often exhibit asynchronous dynamic behavior, despite relatively uniform regional atmospheric and oceanic forcings. This variability may be controlled by a combination of local factors, including glacier and fjord geometry, fjord heat content and circulation, and glacier surface melt. In order to characterize and understand contrasts in adjacent tidewater glacier and fjord dynamics, we made coincident ice-ocean-atmosphere observations at high temporal resolution (minutes to weeks) within a 10 000 km2 area near Uummannaq, Greenland. Water column velocity, temperature and salinity measurements reveal systematic differences in neighboring fjords that imply contrasting circulation patterns. The observed ocean velocity and hydrography, combined with numerical modeling, suggest that subglacial discharge plays a major role in setting fjord conditions. In addition, satellite remote sensing of seasonal ice flow speed and terminus position reveal both speedup and slow-down in response to melt, as well as differences in calving style among the neighboring glaciers. Glacier force budgets and modeling also point toward subglacial discharge as a key factor in glacier behavior. For the studied region, individual glacier and fjord geometry modulate subglacial discharge, which leads to contrasts in both fjord and glacier dynamics.


1988 ◽  
Vol 11 ◽  
pp. 89-94 ◽  
Author(s):  
D. Möller ◽  
B. Ritter

The glacial geodetic contribution to the mass balance and dynamics of ice shelves includes repeated determinations of the absolute position (ϕ,λ,Η) of selected points (using satellite methods), the establishment of relative positions (y,x,Δh) in deformation figures, and height measurements. The results are used to establish ice-flow velocities and directions, strain and rotation rates, and changes in height. Modelling of deformation parameters at a few points over a large ice shelf is made possible by the collocation method. Results of these observations and analysis of Ekström Ice Shelf for the period 1979–87 are reported.


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