scholarly journals Modelling the 20th and 21st century evolution of Hoffellsjökull glacier, SE-Vatnajökull, Iceland

2011 ◽  
Vol 5 (4) ◽  
pp. 961-975 ◽  
Author(s):  
G. Aðalgeirsdóttir ◽  
S. Guðmundsson ◽  
H. Björnsson ◽  
F. Pálsson ◽  
T. Jóhannesson ◽  
...  
Keyword(s):  
Mass Balance ◽  
20Th Century ◽  
21St Century ◽  
Ice Age ◽  
Surface Velocity ◽  
Balance Model ◽  
Climate Change Scenarios ◽  
Differential Gps ◽  
Outlet Glacier ◽  
The Future

Abstract. The Little Ice Age maximum extent of glaciers in Iceland was reached about 1890 AD and most glaciers in the country have retreated during the 20th century. A model for the surface mass balance and the flow of glaciers is used to reconstruct the 20th century retreat history of Hoffellsjökull, a south-flowing outlet glacier of the ice cap Vatnajökull, which is located close to the southeastern coast of Iceland. The bedrock topography was surveyed with radio-echo soundings in 2001. A wealth of data are available to force and constrain the model, e.g. surface elevation maps from ~1890, 1936, 1946, 1989, 2001, 2008 and 2010, mass balance observations conducted in 1936–1938 and after 2001, energy balance measurements after 2001, and glacier surface velocity derived by kinematic and differential GPS surveys and correlation of SPOT5 images. The approximately 20% volume loss of this glacier in the period 1895–2010 is realistically simulated with the model. After calibration of the model with past observations, it is used to simulate the future response of the glacier during the 21st century. The mass balance model was forced with an ensemble of temperature and precipitation scenarios derived from 10 global and 3 regional climate model simulations using the A1B emission scenario. If the average climate of 2000–2009 is maintained into the future, the volume of the glacier is projected to be reduced by 30% with respect to the present at the end of this century. If the climate warms, as suggested by most of the climate change scenarios, the model projects this glacier to almost disappear by the end of the 21st century. Runoff from the glacier is predicted to increase for the next 30–40 yr and decrease after that as a consequence of the diminishing ice-covered area.

scholarly journals Modelling the 20th and 21st century evolution of Hoffellsjökull glacier, SE-Vatnajökull, Iceland

2011 ◽  
Vol 5 (2) ◽  
pp. 1055-1088
Author(s):  
G. Aðalgeirsdóttir ◽  
S. Guðmundsson ◽  
H. Björnsson ◽  
F. Pálsson ◽  
T. Jóhannesson ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
20Th Century ◽  
21St Century ◽  
Ice Age ◽  
Surface Velocity ◽  
Balance Model ◽  
Climate Change Scenarios ◽  
Outlet Glacier ◽  
The Future

Abstract. The Little Ice Age maximum extent of glaciers in Iceland was reached about 1890 AD and most glaciers in the country have retreated during the 20th century. A model for the surface mass balance and the flow of glaciers is used to reconstruct the 20th century retreat history of Hoffellsjökull, a south-flowing outlet glacier of Vatnajökull, which is located close to the southeast coast of Iceland. The bedrock topography was surveyed with radio-echo soundings in 2001. A wealth of data are available to force and constrain the model, e.g. surface elevation maps from ~1890, 1936, 1946, 1986, 2001, 2008 and 2010, mass balance observations conducted in 1936–1938 and after 2001, energy balance measurements after 2001, and glacier surface velocity derived by DGPS and correlation of SPOT5 images. The 21% volume loss of this glacier in the period 1895–2010 is realistically simulated with the model. After calibration of the model with past observations, it is used to simulate the future response of the glacier during the 21st century. The mass balance model was forced with an ensemble of temperature and precipitation scenarios from a study of the effect of climate change on energy production in the Nordic countries (the CES project). If the average climate of 2000–2009 is maintained into the future, the volume of the glacier is projected to be reduced by 30% with respect to the present at the end of this century, and the glacier will almost disappear if the climate warms as suggested by most of the climate change scenarios. Runoff from the glacier is predicted to increase for the next 30–40 years and decrease after that as a consequence of the diminishing ice-covered area.

scholarly journals Reconstruction of the Historical (1750–2020) Mass Balance of Bordu, Kara-Batkak and Sary-Tor Glaciers in the Inner Tien Shan, Kyrgyzstan

2021 ◽  
Vol 9 ◽  
Author(s):  
Lander Van Tricht ◽  
Chloë Marie Paice ◽  
Oleg Rybak ◽  
Rysbek Satylkanov ◽  
Victor Popovnin ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Climatic Conditions ◽  
Tien Shan ◽  
Ice Age ◽  
Balance Model ◽  
Mass Balances ◽  
Specific Mass ◽  
The Future ◽  
The Mean

The mean specific mass balance of a glacier represents the direct link between a glacier and the local climate. Hence, it is intensively monitored throughout the world. In the Kyrgyz Tien Shan, glaciers are of crucial importance with regard to water supply for the surrounding areas. It is therefore essential to know how these glaciers behave due to climate change and how they will evolve in the future. In the Soviet era, multiple glaciological monitoring programs were initiated but these were abandoned in the nineties. Recently, they have been re-established on several glaciers. In this study, a reconstruction of the mean specific mass balance of Bordu, Kara-Batkak and Sary-Tor glaciers is obtained using a surface energy mass balance model. The model is driven by temperature and precipitation data acquired by combining multiple datasets from meteorological stations in the vicinity of the glaciers and tree rings in the Kyrgyz Tien Shan between 1750 and 2020. Multi-annual mass balance measurements integrated over elevation bands of 100 m between 2013 and 2020 are used for calibration. A comparison with WGMS data for the second half of the 20th century is performed for Kara-Batkak glacier. The cumulative mass balances are also compared with geodetic mass balances reconstructed for different time periods. Generally, we find a close agreement, indicating a high confidence in the created mass balance series. The last 20 years show a negative mean specific mass balance except for 2008–2009 when a slightly positive mass balance was found. This indicates that the glaciers are currently in imbalance with the present climatic conditions in the area. For the reconstruction back to 1750, this study specifically highlights that it is essential to adapt the glacier geometry since the end of the Little Ice Age in order to not over- or underestimate the mean specific mass balance. The datasets created can be used to get a better insight into how climate change affects glaciers in the Inner Tien Shan and to model the future evolution of these glaciers as well as other glaciers in the region.

scholarly journals Modelling the evolution of Vadret da Morteratsch, Switzerland, since the Little Ice Age and into the future

2014 ◽  
Vol 60 (224) ◽  
pp. 1155-1168 ◽  
Author(s):  
Harry Zekollari ◽  
Johannes Jakob Fürst ◽  
Philippe Huybrechts
Keyword(s):  
Mass Balance ◽  
Little Ice Age ◽  
Flow Model ◽  
High Elevation ◽  
Ice Age ◽  
Balance Model ◽  
Monthly Precipitation ◽  
Initial State ◽  
Ice Dynamics ◽  
The Future

AbstractWe use a 3-D higher-order glacier flow model for Vadret da Morteratsch, Engadin, Switzerland, to simulate its strong retreat since the end of the Little Ice Age (LIA) and to project its future disintegration under a warming climate. The flow model, coupled to a 2-D energy-balance model, is initialized with the known maximum glacier extent during the LIA and subsequently forced with mean monthly precipitation and temperature records. To correctly reproduce the observed retreat of the glacier front for the period 1864–2010, additional mass-balance perturbations are required to account for uncertainties in the initial state, the mass-balance model and climate variations not captured by the ambient meteorological records. Changes in glacier volume and area are in good agreement with additional information from historical topographic maps. Under constant 2001–10 climate conditions, a strong retreat and mass loss continue and Vadret da Morteratsch disconnects from its main tributary, Vadret Pers, before 2020. The future glacier evolution is analysed in detail to understand the timing and rate of retreat, and to assess the role of ice dynamics. Assuming a linearly increasing warming of >3°C by 2100, only isolated and largely stagnant ice patches remain at high elevation.

scholarly journals Upper Colorado River Basin 20th century droughts under 21st century warming: Plausible scenarios for the future

2021 ◽  
Vol 21 ◽  
pp. 100206
Author(s):  
Connie A. Woodhouse ◽  
Rebecca M. Smith ◽  
Stephanie A. McAfee ◽  
Gregory T. Pederson ◽  
Gregory J. McCabe ◽  
...  
Keyword(s):  
20Th Century ◽  
River Basin ◽  
21St Century ◽  
Colorado River ◽  
Colorado River Basin ◽  
Upper Colorado River Basin ◽  
The Future

scholarly journals Glacier dynamics at Helheim and Kangerdlugssuaq glaciers, southeast Greenland, since the Little Ice Age

2014 ◽  
Vol 8 (4) ◽  
pp. 1497-1507 ◽  
Author(s):  
S. A. Khan ◽  
K. K. Kjeldsen ◽  
K. H. Kjær ◽  
S. Bevan ◽  
A. Luckman ◽  
...  
Keyword(s):  
Mass Balance ◽  
Little Ice Age ◽  
Ice Age ◽  
Short Term ◽  
Velocity Change ◽  
Outlet Glacier ◽  
Episodic Events ◽  
Highly Sensitive ◽  
Decadal Scale ◽  
Speed Up

Abstract. Observations over the past decade show significant ice loss associated with the speed-up of glaciers in southeast Greenland from 2003, followed by a deceleration from 2006. These short-term, episodic, dynamic perturbations have a major impact on the mass balance on the decadal scale. To improve the projection of future sea level rise, a long-term data record that reveals the mass balance beyond such episodic events is required. Here, we extend the observational record of marginal thinning of Helheim and Kangerdlugssuaq glaciers from 10 to more than 80 years. We show that, although the frontal portion of Helheim Glacier thinned by more than 100 m between 2003 and 2006, it thickened by more than 50 m during the previous two decades. In contrast, Kangerdlugssuaq Glacier underwent minor thinning of 40–50 m from 1981 to 1998 and major thinning of more than 100 m after 2003. Extending the record back to the end of the Little Ice Age (prior to 1930) shows no thinning of Helheim Glacier from its maximum extent during the Little Ice Age to 1981, while Kangerdlugssuaq Glacier underwent substantial thinning of 230 to 265 m. Comparison of sub-surface water temperature anomalies and variations in air temperature to records of thickness and velocity change suggest that both glaciers are highly sensitive to short-term atmospheric and ocean forcing, and respond very quickly to small fluctuations. On century timescales, however, multiple external parameters (e.g. outlet glacier shape) may dominate the mass change. These findings suggest that special care must be taken in the projection of future dynamic ice loss.

Technology and Disabilities in the Century Ahead

2011 ◽  
pp. 2077-2081
Author(s):  
Ray Kurzweil
Keyword(s):  
20Th Century ◽  
21St Century ◽  
Current Level ◽  
Rate Of Change ◽  
The World ◽  
The Future ◽  
The Disabled ◽  
Speed Up ◽  
Technology Trends ◽  
Over Time

I have been involved in inventing since I was five, and I quickly realized that for an invention to succeed, you have to target the world of the future. But what would the future be like? To find out, I became a student of technology trends and began to develop mathematical models of different technologies: computation, miniaturization, evolution over time. I have been doing that for 25 years, and it has been remarkable to me how powerful and predictive these models are. Now, before I show you some of these models and then try to build with you some of the scenarios for the future—and, in particular, focus on how these will benefit technology for the disabled—I would like to share one trend that I think is particularly profound and that many people fail to take into consideration. It is this: the rate of progress—what I call the “paradigmshift rate”—is itself accelerating. We are doubling this paradigm-shift rate every decade. The whole 20th century was not 100 years of progress as we know it today, because it has taken us a while to speed up to the current level of progress. The 20t h century represented about 20 years of progress in terms of today’s rate. And at today’s rate of change, we will achieve an amount of progress equivalent to that of the whole 20th century in 14 years, then as the acceleration continues, in 7 years. The progress in the 21st century will be about 1,000 times greater than that in the 20th century, which was no slouch in terms of change.

scholarly journals Drama in Ho Chi Minh City literature and art life

2015 ◽  
Vol 18 (4) ◽  
pp. 47-60
Author(s):  
Thuy Trung Luu
Keyword(s):  
20Th Century ◽  
21St Century ◽  
Performance Art ◽  
Early Time ◽  
High Time ◽  
Ho Chi Minh City ◽  
Late 20Th Century ◽  
Early 21St Century ◽  
The Future ◽  
History Of

In the history of Vietnamese drama, Saigon was one of the places absorbing Western drama from the early time. Although drama in Saigon-Ho Chi Minh City didn’t develop in a smooth and straight way, it was a continuous and unbroken process. This process brought in strong development of drama in Ho Chi Minh city in two decades of the late 20th century and the early 21st century. However, in recent years, drama in Ho Chi Minh City seems to proceed slowly, which reflects some irrational aspects from drama script, performance art to performance operation. Therefore, it’s high time to review the whole history of drama in Saigon-Ho Chi Minh City to collect experiences for the steady development of drama in this City in the future.

scholarly journals Glacier dynamics over the last quarter of a century at Jakobshavn Isbræ

2015 ◽  
Vol 9 (5) ◽  
pp. 4865-4892
Author(s):  
I. S. Muresan ◽  
S. A. Khan ◽  
A. Aschwanden ◽  
C. Khroulev ◽  
T. Van Dam ◽  
...  
Keyword(s):  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
21St Century ◽  
Greenland Ice Sheet ◽  
Outlet Glacier ◽  
The Past ◽  
Glacier Dynamics ◽  
The Future ◽  
Oceanic Forcing

Abstract. Observations over the past two decades show substantial ice loss associated with the speedup of marine terminating glaciers in Greenland. Here we use a regional 3-D outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) located in west Greenland. Using atmospheric and oceanic forcing we tune our model to reproduce the observed frontal changes of JI during 1990–2014. We identify two major accelerations. The first occurs in 1998, and is triggered by moderate thinning prior to 1998. The second acceleration, which starts in 2003 and peaks in summer 2004, is triggered by the final breakup of the floating tongue, which generates a reduction in buttressing at the JI terminus. This results in further thinning, and as the slope steepens inland, sustained high velocities have been observed at JI over the last decade. As opposed to other regions on the Greenland Ice Sheet (GrIS), where dynamically induced mass loss has slowed down over recent years, both modelled and observed results for JI suggest a continuation of the acceleration in mass loss. Further, we find that our model is not able to capture the 2012 peak in the observed velocities. Our analysis suggests that the 2012 acceleration of JI is likely the result of an exceptionally long melt season dominated by extreme melt events. Considering that such extreme surface melt events are expected to intensify in the future, our findings suggest that the 21st century projections of the GrIS mass loss and the future sea level rise may be larger than predicted by existing modelling results.

scholarly journals Drought assessment and trends analysis from 20th century to 21st century over China

2015 ◽  
Vol 371 ◽  
pp. 89-94 ◽  
Author(s):  
X. L. Yang ◽  
L. L. Ren ◽  
R. Tong ◽  
Y. Liu ◽  
X. R. Cheng ◽  
...  
Keyword(s):  
20Th Century ◽  
21St Century ◽  
Climate Models ◽  
Local Economic Development ◽  
Standardized Precipitation Index ◽  
Cmip5 Models ◽  
Climate Projections ◽  
Future Period ◽  
Drought Assessment ◽  
The Future

Abstract. Droughts are becoming the most expensive natural disasters in China and have exerted serious impacts on local economic development and ecological environment. The fifth phase of the Coupled Model Intercomparison Project (CMIP5) provides a unique opportunity to assess scientific understanding of climate variability and change over a range of historical and future period. In this study, fine-resolution multimodel climate projections over China are developed based on 7 CMIP5 climate models under RCP8.5 emissions scenarios by means of Bilinear Interpolation and Bias Correction. The results of downscaled CMIP5 models are evaluated over China by comparing the model outputs with the England Reanalysis CRU3.1 from 1951 to 2000. Accordingly, the results from the output of downscaled models are used to calculate the Standardized Precipitation Index (SPI). Time series of SPI has been used to identify drought from 20th century to 21st century over China. The results show that, most areas of China are projected to become wetter as a consequence of increasing precipitation under RCP8.5 scenarios. Detailed examination shows that the SPI show a slightly increasing trend in the future period for the most parts of China, but drought in Southwest region of China will become the norm in the future RCP8.5 scenarios.

scholarly journals Recent Climatic Mass Balance of the Schiaparelli Glacier at the Monte Sarmiento Massif and Reconstruction of Little Ice Age Climate by Simulating Steady-State Glacier Conditions

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 272
Author(s):  
Stephanie Suzanne Weidemann ◽  
Jorge Arigony-Neto ◽  
Ricardo Jaña ◽  
Guilherme Netto ◽  
Inti Gonzalez ◽  
...  
Keyword(s):  
Steady State ◽  
Mass Balance ◽  
Air Temperature ◽  
Little Ice Age ◽  
Similar Rate ◽  
Climatic Conditions ◽  
Ice Age ◽  
Balance Model ◽  
Climate Conditions ◽  
Recent Climate

The Cordillera Darwin Icefield loses mass at a similar rate as the Northern and Southern Patagonian Icefields, showing contrasting individual glacier responses, particularly between the north-facing and south-facing glaciers, which are subject to changing climate conditions. Detailed investigations of climatic mass balance processes on recent glacier behavior are not available for glaciers of the Cordillera Darwin Icefield and surrounding icefields. We therefore applied the coupled snow and ice energy and mass balance model in Python (COSIPY) to assess recent surface energy and mass balance variability for the Schiaparelli Glacier at the Monte Sarmiento Massif. We further used COSIPY to simulate steady-state glacier conditions during the Little Ice Age using information of moraine systems and glacier areal extent. The model is driven by downscaled 6-hourly atmospheric data and high resolution precipitation fields, obtained by using an analytical orographic precipitation model. Precipitation and air temperature offsets to present-day climate were considered to reconstruct climatic conditions during the Little Ice Age. A glacier-wide mean annual climatic mass balance of −1.8 ± 0.36 m w.e. a − 1 was simulated between between April 2000 and March 2017. An air temperature decrease between −0.9 ° C and −1.7 ° C in combination with a precipitation offset of up to +60% to recent climate conditions is necessary to simulate steady-state conditions for Schiaparelli Glacier in 1870.

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