Small ice caps in climate models

1997 ◽  
pp. 289-297
Author(s):  
Gerald R. North ◽  
Kwang-Yul Kin ◽  
Wan-Ho Lee
Keyword(s):  
Climate Models ◽  
Ice Caps

scholarly journals Automatic weather stations for basic and applied glaciological research

1969 ◽  
pp. 69-72 ◽  
Author(s):  
Michele Citterio ◽  
Dirk Van As ◽  
Andreas P. Ahlstrøm ◽  
Morten L. Andersen ◽  
Signe B. Andersen ◽  
...  
Keyword(s):  
Climate Models ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Feasibility Studies ◽  
Lessons Learned ◽  
Physical Parameters ◽  
Ice Caps ◽  
Technological Advances ◽  
Weather Stations ◽  
The Impact

Since the early 1980s, the Geological Survey of Denmark and Greenland (GEUS) glaciology group has developed automatic weather stations (AWSs) and operated them on the Greenland ice sheet and on local glaciers to support glaciological research and monitoring projects (e.g. Olesen & Braithwaite 1989; Ahlstrøm et al. 2008). GEUS has also operated AWSs in connection with consultancy services in relation to mining and hydropower pre-feasibility studies (Colgan et al. 2015). Over the years, the design of the AWS has evolved, partly due to technological advances and partly due to lessons learned in the fi eld. At the same time, we have kept the initial goal in focus: long-term, year-round accurate recording of ice ablation, snow depth and the physical parameters that determine the energy budget of glacierised surfaces. GEUS has an extensive record operating AWSs in the harsh Arctic environment of the diverse ablation areas of the Greenland ice sheet, glaciers and ice caps (Fig. 1). Th e current GEUS-type AWS (Fig. 2) records meteorological, surface and sub-surface variables, including accumulation and ablation, as well as for example ice velocity. A large part of the data is transmitted by satellite near real-time to support ongoing applications, fi eld activities and the planning of maintenance visits. Th e data have been essential for assessing the impact of climate change on land ice. Th e data are also crucial for calibration and validation of satellite-based observations and climate models (van As et al. 2014).

scholarly journals An assessment of uncertainties in using volume-area modelling for computing the twenty-first century glacier contribution to sea-level change

2011 ◽  
Vol 5 (3) ◽  
pp. 1655-1695 ◽  
Author(s):  
A. B. A. Slangen ◽  
R. S. W. van de Wal
Keyword(s):  
Mass Balance ◽  
Sea Level ◽  
Climate Models ◽  
Climate Model ◽  
Sea Level Change ◽  
Total Uncertainty ◽  
Ice Caps ◽  
Level Change ◽  
Initial Volume ◽  
Temperature And Precipitation

Abstract. A large part of present-day sea-level change is formed by the melt of glaciers and ice caps (GIC). This study focuses on the uncertainties in the calculation of the GIC contribution on a century timescale. The model used is based on volume-area scaling, combined with the mass balance sensitivity of the GIC. We assess different aspects that contribute to the uncertainty in the prediction of the contribution of GIC to future sea-level rise, such as (1) the volume-area scaling method (scaling constant), (2) the choice of glacier inventory, (3) the imbalance of glaciers with climate, (4) the mass balance sensitivity, and (5) the climate models. Additionally, a comparison of the model results to the 20th century GIC contribution is presented. We find that small variations in the scaling constant cause significant variations in the initial volume of the glaciers, but only limited variations in the glacier volume change. If two existing glacier inventories are tuned such that the initial volume is the same, the GIC sea-level contribution over 100 yr differs by 0.027 m. It appears that the mass balance sensitivity is also important: variations of 20 % in the mass balance sensitivity have an impact of 17 % on the resulting sea-level projections. Another important factor is the choice of the climate model, as the GIC contribution to sea-level change largely depends on the temperature and precipitation taken from climate models. Combining all the uncertainties examined in this study leads to a total uncertainty of 4.5 cm or 30 % in the GIC contribution to global mean sea level. Reducing the variance in the climate models and improving the glacier inventories will significantly reduce the uncertainty in calculating the GIC contributions, and are therefore crucial actions to improve future sea-level projections.

Statistical Analysis of Global Surface Temperature and Sea Level Using Cointegration Methods

2012 ◽  
Vol 25 (22) ◽  
pp. 7822-7833 ◽  
Author(s):  
Torben Schmith ◽  
Søren Johansen ◽  
Peter Thejll
Keyword(s):  
Surface Temperature ◽  
Sea Level ◽  
Radiative Forcing ◽  
Climate Models ◽  
Cointegration Analysis ◽  
Sea Levels ◽  
Ice Caps ◽  
Physically Based ◽  
Ice Sheet Dynamics ◽  
Global Sea Level

Abstract Global sea level rise is widely understood as a consequence of thermal expansion and the melting of glaciers and land-based ice caps. Because of the lack of representation of ice-sheet dynamics in present-day physically based climate models, semiempirical models have been applied as an alternative for projecting future sea levels. There are, however, potential pitfalls in this because of the trending nature of the time series. A statistical method called cointegration analysis that is capable of handling such peculiarities is applied to observed global sea level and land–ocean surface temperature. The authors find a relationship between sea level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. They further find that the warming episode in the 1940s is exceptional in the sense that sea level and warming deviate from the expected relationship. This suggests that this warming episode is mainly due to internal dynamics of the ocean rather than external radiative forcing. On the other hand, the present warming follows the expected relationship, suggesting that it is mainly due to radiative forcing. In a second step, the total radiative forcing is used as an explanatory variable, but it is unexpectedly found that the sea level does not depend on the forcing. The authors hypothesize that this is due to a long adjustment time scale of the ocean and show that the number of years of data needed to build statistical models that have the relationship expected from physics exceeds what is currently available by a factor of almost 10.

scholarly journals Glacial Inception on Baffin Island: The Interaction of Ice Flow and Meteorology

2018 ◽  
Author(s):  
Leah Birch ◽  
Timothy Cronin ◽  
Eli Tziperman
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Forecast Model ◽  
Horizontal Resolution ◽  
Global Climate Models ◽  
Baffin Island ◽  
Ice Flow ◽  
Geological Evidence ◽  
Ice Caps ◽  
Outer Domain

Abstract. Over the past 0.8 million years, 100 kyr ice ages have dominated Earth's climate with geological evidence suggesting the last glacial inception began in the mountains of Baffin Island. Currently, state-of-the-art global climate models (GCMs) have difficulty simulating glacial inception, possibly due in part to their coarse horizontal resolution and the neglect of ice flow dynamics in some models. We attempt to address the initial inception problem on Baffin Island by asynchronously coupling the Weather Research and Forecast model (WRF), configured as a high resolution inner domain over Baffin and an outer domain incorporating much of North America, to an ice flow model using the shallow ice approximation. The mass balance is calculated from WRF simulations, and used to drive the ice model, which updates the ice extent and elevation, that then serve as inputs to the next WRF run. We drive the regional WRF configuration using atmospheric boundary conditions from 1986 that correspond to a relatively cold summer, and with 115 kya insolation. Initially, ice accumulates on mountain glaciers, driving downslope ice flow which expands the size of the ice caps. However, continued iterations of the atmosphere and ice models reveal a stagnation of the ice sheet on Baffin Island, driven by melting due to warmer temperatures at the margins of the ice caps. This warming is caused by changes in the larger-scale circulation that are forced by elevation changes due to the ice growth. A stabilizing feedback between ice elevation and atmospheric circulation thus prevents full inception from occurring.

Update on GRACE/GRACE-FO continuity in mass loss of the glaciers and big ice sheets.

2020 ◽  
Author(s):  
Isabella Velicogna ◽  
Mohajerani Yara ◽  
Enrico Ciraci ◽  
Felix Landerer ◽  
David Wiese
Keyword(s):  
Mass Balance ◽  
Climate Models ◽  
Global Climate ◽  
Ice Sheets ◽  
Reanalysis Data ◽  
Global Climate Models ◽  
Steady Increase ◽  
Atlantic Sector ◽  
Surface Mass ◽  
Ice Caps

<p>The GRACE missions have changed the way that we measure mass changes of ice sheets, glaciers and ice caps, with quantied uncertainties that factor processing errors, atmospheric and oceanic corrections, and removal of glacial isostatic adjustment (GIA). We present GRACE/GRACE-FO estimates of mass balance over the Greenland and Antarctic Ice Sheets and the World’s glaciers and ice caps (GIC). The data gap between missions is filled with GRACE-calibrated results from the input-output method for ice sheets and surface mass balance (SMB) reconstructions from regional atmospheric climate models and MERRA-2 reanalysis data for the glaciers and ice caps. Over Greenland, we report low losses during the cold years of 2017-2018 followed by record melt in 2019 and an onset of rapid melt for 2020. As warm air and ocean masses get blocked over Greenland more frequently because of interactions between the wobbling jet stream and topography, we observe more high melt events in this decade than recorded in prior centuries. In Antarctica, the ongoing rapid loss in West Antarctica dominates the mass balance, but we observe a steady increase in snowfall in the Atlantic sector of East Antarctica. The exercise provides a mass balance record that can be continuously improved with better corrections and improved processing, with reduced errors, so that we can provide better constraints for ice sheet models in charge of sea level projections and improve the validation of various Earth system models and global climate models.</p>

scholarly journals The role of regional feedbacks in glacial inception on Baffin Island: the interaction of ice flow and meteorology

2018 ◽  
Vol 14 (10) ◽  
pp. 1441-1462
Author(s):  
Leah Birch ◽  
Timothy Cronin ◽  
Eli Tziperman
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Horizontal Resolution ◽  
Global Climate Models ◽  
Baffin Island ◽  
Ice Flow ◽  
Geological Evidence ◽  
Ice Caps ◽  
Outer Domain

Abstract. Over the past 0.8 million years, 100 kyr ice ages have dominated Earth's climate with geological evidence suggesting the last glacial inception began in the mountains of Baffin Island. Currently, state-of-the-art global climate models (GCMs) have difficulty simulating glacial inception, possibly due in part to their coarse horizontal resolution and the neglect of ice flow dynamics in some models. We attempt to address the role of regional feedbacks in the initial inception problem on Baffin Island by asynchronously coupling the Weather Research and Forecast (WRF) model, configured as a high-resolution inner domain over Baffin and an outer domain incorporating much of North America, to an ice flow model using the shallow ice approximation. The mass balance is calculated from WRF simulations and used to drive the ice model, which updates the ice extent and elevation, that then serve as inputs to the next WRF run. We drive the regional WRF configuration using atmospheric boundary conditions from 1986 that correspond to a relatively cold summer, and with 115 kya insolation. Initially, ice accumulates on mountain glaciers, driving downslope ice flow which expands the size of the ice caps. However, continued iterations of the atmosphere and ice models reveal a stagnation of the ice sheet on Baffin Island, driven by melting due to warmer temperatures at the margins of the ice caps. This warming is caused by changes in the regional circulation that are forced by elevation changes due to the ice growth. A stabilizing feedback between ice elevation and atmospheric circulation thus prevents full inception from occurring.

scholarly journals Modeling of Future Sea Level Rise Through Melting Glaciers

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Manoj Kumar Singh ◽  
Bharat Raj Singh
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
21St Century ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Sea Level Changes ◽  
Systematic Analysis ◽  
Ice Caps ◽  
Mountain Glaciers

The aim of this paper is to project 21st century volume changes of all mountain glacier and ice caps and to provide systematic analysis of uncertainties originating from different sources in the and their contribution to sea level rise and the assessment of uncertainties. Trends in global climate warming and sea level rise are observed during the last 100-years which both, according to global climate models, will continue in the future Intergovernmental Panel on Climate Change (IPCC) State-of-threat knowledge on climate, ocean and land processes identifies melting mountain glaciers and ice caps, after ocean thermal expansion, as the currently second major contributor to sea level rise. However, both the observations and models on sea level changes carry a variety of uncertainties. In this section, by following the question-answer concept, I will briefly present the importance of global sea level change for society, the current state of knowledge of sea level changes in response to climate change and the attempts to project future sea level changes until 2100 including discussion on related uncertainties. Melting mountain glaciers and ice caps (MG&IC) are the second largest contributor to rising sea level after thermal expansion of the oceans and are likely to remain the dominant glaciological contributor to rising sea level in the 21st century. The aim of this work is to project 21st century volume changes of all MG&IC and to provide systematic analysis of uncertainties originating from different sources in the calculation. I provide an ensemble of 21st century volume rojections for all MG&IC from the World Glacier Inventory by modeling the surface mass balance coupled with volume-area-length scaling and forced with temperature and precipitation scenarios from four Global Climate Models (GCMs). By upscaling the volume projections through a regionally differentiated approach to all MG&IC outside Greenland and Antarctica (514,380 km2) I stimated total volume loss for the time period 2001-2100 to range from 0.039 to 0.150 m sea level equivalent. While three GCMs agree that Alaskan glaciers are the main contributors to the projected sea level rise, one GCM projected the largest total volume loss mainly due to Arctic MG&IC.

scholarly journals Dynamic simulations of Vatnajökull ice cap from 1980 to 2300

2019 ◽  
Vol 66 (255) ◽  
pp. 97-112 ◽  
Author(s):  
Louise Steffensen Schmidt ◽  
Guðfinna Ađalgeirsdóttir ◽  
Finnur Pálsson ◽  
Peter L. Langen ◽  
Sverrir Guđmundsson ◽  
...  
Keyword(s):  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Lapse Rate ◽  
Dynamic Simulations ◽  
Climate Conditions ◽  
Temperature Lapse Rate ◽  
Ice Caps ◽  
Ice Cap ◽  
Rcp 8.5

AbstractLike most ice caps and glaciers worldwide, Icelandic glaciers are retreating in a warming climate. Here, the evolution of Vatnajökull ice cap, Iceland, from 1980 to 2300 is simulated by forcing the Parallel Ice Sheet Model (PISM) with output from Regional Climate Models (RCMs). For climate simulations of the recent past, HARMONIE-AROME reanalysis-forced simulations are used, while for future climate conditions, high-resolution (5.5 km) simulations from the RCM HIRHAM5 are used in addition to available CORDEX simulations (12 km). The glacier evolution is modelled using the RCP 4.5 and RCP 8.5 scenarios until 2100. To extend the time series, the 2081–2100 climate forcing is repeated until 2300. For RCP 4.5, the ice cap loses 31–64% of its volume and 13–37% of its area by 2300 depending on the used model forcing. For RCP 8.5, the volume decrease is 51–94% and the area decrease is 24–80% by 2300. In addition, the effect of elevation feedbacks is investigated by adding a precipitation and temperature lapse rate to the HIRHAM5 simulations. By 2300, the lapse rate runs have a 9–14% smaller volume and a 9–20% smaller area than the runs without a lapse rate correction.

scholarly journals How to Cope with Climate’s Complexity?

2009 ◽  
Vol 17 (2) ◽  
pp. 371-402
Author(s):  
Michel Crucifix
Keyword(s):  
Dynamical Systems ◽  
Bayesian Statistics ◽  
Climate Models ◽  
Practical Interest ◽  
Dissipative Structures ◽  
Macroscopic Scale ◽  
Linear Dynamical Systems ◽  
Ice Caps ◽  
Vast Range ◽  
Modelling Approach

Climate exhibits a vast range of dissipative structures. Some have characteristic times of a few days; others evolve over thousands of years. All these structures are interdependent; in other words, they communicate. It is often considered that the only way to cope with climate complexity is to integrate the equations of atmospheric and oceanic motion with the finest possible mesh. Is this the sole strategy? Aren’t we missing another characteristic of the climate system: its ability to destroy and generate information at the macroscopic scale? Paleoclimatologists consider that much of this information is present in palaeoclimate archives. It is therefore natural to build climate models such as to get the most of these archives. The strategy proposed here is based on Bayesian statistics and low-order non-linear dynamical systems, in a modelling approach that explicitly includes the effects of uncertainties. Its practical interest is illustrated through the problem of the timing of the next great glaciation. Is glacial inception overdue or do we need to wait for another 50,000 years before ice caps grow again? Our results indicate a glaciation inception in 50,000 years.

Impact of north-hemispherical cryosphere on late Pliensbachian – early Toarcian climate and environment evolution

2021 ◽  
pp. SP514-2021-11
Author(s):  
Wolfgang Ruebsam ◽  
Lorenz Schwark
Keyword(s):  
Sea Level ◽  
Climate Models ◽  
Parallel Evolution ◽  
Causal Mechanism ◽  
Polar Regions ◽  
Environmental Response ◽  
Northern Margin ◽  
Ice Caps ◽  
Historical View ◽  
Tethys Ocean

AbstractThe historical view of an equable Jurassic greenhouse world has been challenged by recent studies documenting recurrent alternation between contrasting climate modes. Cooling of high-latitudinal areas may have been caused by orogenic processes at the northern margin of the Tethys Ocean that reduced the heat-transport towards polar regions. Warm phases correlate to periods of intensified volcanism. The Jenkyns Event occurred during the transition from a late Pliensbachian Icehouse into an early Toarcian Greenhouse. Parallel evolution of different environmental processes, including sea level, climate, and carbon cycle indicate a causal mechanism tied to astronomical forcing. Insolation-controlled variations in the extent of the cryosphere (ice caps and permafrost) facilitated both orbitally-paced sea level cycles via waxing and waning of polar ice caps and negative carbon isotope excursions via the release of cryosphere-bound 12C-enriched carbon. This review and synthesis of sedimentological, geochemical, and paleontological paleoenvironment indicators and of simulations from climate models aims at reconstruction of particularly the high-latitudinal environmental condition during late Pliensbachian to early Toarcian times. Focus is laid on the extent of regions that were potentially suitable for hosting a cryosphere. Environmental response to cryosphere dynamics is considered to have been a key component of the Jenkyns Event.

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