scholarly journals Numerical modelling of the ice sheet in western Dronning Maud Land, East Antarctica: impacts of present, past and future climates

2000 ◽  
Vol 46 (152) ◽  
pp. 54-66 ◽  
Author(s):  
J. O. Näslund ◽  
J. L. Fastook ◽  
P. Holmlund
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Ice Sheet ◽  
East Antarctica ◽  
Ice Thickness ◽  
Mountain Range ◽  
Climate Change Scenarios ◽  
Dronning Maud Land ◽  
Global Sea Level ◽  
Basal Melting

AbstractTime-dependent ice-sheet modelling of a 176 000 km2 area in western Dronning Maud Land, East Antarctica, provided information on the ice sheet’s response to six climate-change scenarios. Another experiment was done to study changes in ice thickness, flow and basal temperature conditions between the present ice configuration and a simulated maximum palaeo-ice sheet. The input to the model included new datasets of bed and surface topography compiled for this study. The results of the six climate-change experiments, including a 0.5°C per century global-warming scenario, show that the ice sheet has a robust behaviour with respect to the different climate changes. The maximum change in ice volume was <5% of the initial volume in all climate runs. This is for only relatively short-term climate changes without major changes in global sea level, and also a simulated ice sheet without an ice shelf. The modelled long-term response time of the ice sheet, 20 kyr or more, indicates that the ice sheet may still be adjusting to the climate change that ended the Last Glacial Maximum. In the maximum palaeo-ice-sheet simulation, with a 5°C climate cooling and the grounding line located at the continental-shelf margin, ice thickness increased drastically downstream from the Heimefrontfjella mountain range but remained basically unaffected on the upstream polar plateau. Compared to present conditions, complex changes in basal temperatures were observed. The extent of areas with basal melting increased, for example in the deep trough of the Veststraumen ice stream. Areas at intermediate elevations in the landscape also experienced increased basal temperatures, with significant areas reaching the melting point. In contrast, high-altitude areas that today are clearly cold-based, such as around Heimefrontfjella and Vestfjella and the Högisen dome, experienced a 5–10°C decrease in basal temperatures in the palaeo-ice-sheet reconstruction. The results suggest that the alpine landscape within these mountain regions was formed by wet-based local glaciers and ice sheets prior to the late Cenozoic.

scholarly journals Radar diagnosis of the subglacial conditions in Dronning Maud Land, East Antarctica

2012 ◽  
Vol 6 (3) ◽  
pp. 1781-1837
Author(s):  
S. Fujita ◽  
P. Holmlund ◽  
K. Matsuoka ◽  
H. Enomoto ◽  
K. Fukui ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
East Antarctica ◽  
Thickness Variation ◽  
Ice Thickness ◽  
High Mountains ◽  
Anomalous Increase ◽  
Dronning Maud Land ◽  
Basal Melting ◽  
The Relationship ◽  
Subglacial Environments

Abstract. In order to better understand the spatial distribution of subglacial environments, ground-based radar sounding data for a total distance of ~3300 km across Dronning Maud Land, East Antarctica, were analyzed. The relationship between geometrically corrected bed returned power [Pcbed]dB in decibels and ice thickness H was examined. When H is smaller, [Pcbed]dB was found to decrease simply with increasing H, which is explicable by the thickness variation of dielectric attenuation. However, an anomalous increase in [Pcbed]dB at larger H occurred, which was independent of the choice of radar frequencies or radar-pulse widths. We suggest that the existence of water at the ice/substrate interfaces at larger H caused this anomalous increase. We herein propose a new analytical method using these features to delineate frozen and temperate bed areas. Approximately two-thirds of the investigated area was found to have a temperate bed. Basal melting tends to occur when H is larger and the surface elevation is lower. In other words, beds inland of the ice sheet tend to be temperate, with the exception of subglacial high mountains. In contrast, beds of coastal areas tend to be frozen, with the exception of fast-flowing ice at subglacial lowland or troughs. These observations suggest that subglacial water is dominantly produced at the bed of wide inland plateau and that the water is discharged to the sea dominantly through a bed of fast-flowing ice. We also found that a 20-km-wide bed in the subglacial high mountains of an inland plateau near Dome Fuji is frozen, suggesting the existence of very old ice above the bed.

scholarly journals Mapping current and potential future distributions of the oak tree (Quercus aegilops) in the Kurdistan Region, Iraq

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Nabaz R. Khwarahm
Keyword(s):  
Climate Change ◽  
Habitat Suitability ◽  
Environmental Variables ◽  
Climate Changes ◽  
Future Climate ◽  
Annual Precipitation ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Kurdistan Region ◽  
Oak Tree

Abstract Background The oak tree (Quercus aegilops) comprises ~ 70% of the oak forests in the Kurdistan Region of Iraq (KRI). Besides its ecological importance as the residence for various endemic and migratory species, Q. aegilops forest also has socio-economic values—for example, as fodder for livestock, building material, medicine, charcoal, and firewood. In the KRI, Q. aegilops has been degrading due to anthropogenic threats (e.g., shifting cultivation, land use/land cover changes, civil war, and inadequate forest management policy) and these threats could increase as climate changes. In the KRI and Iraq as a whole, information on current and potential future geographical distributions of Q. aegilops is minimal or not existent. The objectives of this study were to (i) predict the current and future habitat suitability distributions of the species in relation to environmental variables and future climate change scenarios (Representative Concentration Pathway (RCP) 2.6 2070 and RCP8.5 2070); and (ii) determine the most important environmental variables controlling the distribution of the species in the KRI. The objectives were achieved by using the MaxEnt (maximum entropy) algorithm, available records of Q. aegilops, and environmental variables. Results The model demonstrated that, under the RCP2.6 2070 and RCP8.5 2070 climate change scenarios, the distribution ranges of Q. aegilops would be reduced by 3.6% (1849.7 km2) and 3.16% (1627.1 km2), respectively. By contrast, the species ranges would expand by 1.5% (777.0 km2) and 1.7% (848.0 km2), respectively. The distribution of the species was mainly controlled by annual precipitation. Under future climate change scenarios, the centroid of the distribution would shift toward higher altitudes. Conclusions The results suggest (i) a significant suitable habitat range of the species will be lost in the KRI due to climate change by 2070 and (ii) the preference of the species for cooler areas (high altitude) with high annual precipitation. Conservation actions should focus on the mountainous areas (e.g., by establishment of national parks and protected areas) of the KRI as climate changes. These findings provide useful benchmarking guidance for the future investigation of the ecology of the oak forest, and the categorical current and potential habitat suitability maps can effectively be used to improve biodiversity conservation plans and management actions in the KRI and Iraq as a whole.

scholarly journals Impact of an accelerated melting of Greenland on malaria distribution over Africa

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alizée Chemison ◽  
Gilles Ramstein ◽  
Adrian M. Tompkins ◽  
Dimitri Defrance ◽  
Guigone Camus ◽  
...  
Keyword(s):  
Climate Change ◽  
Malaria Transmission ◽  
Ice Sheet ◽  
Transmission Risk ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Climate Change Risk ◽  
System A ◽  
Climate Simulations ◽  
The Impact

AbstractStudies about the impact of future climate change on diseases have mostly focused on standard Representative Concentration Pathway climate change scenarios. These scenarios do not account for the non-linear dynamics of the climate system. A rapid ice-sheet melting could occur, impacting climate and consequently societies. Here, we investigate the additional impact of a rapid ice-sheet melting of Greenland on climate and malaria transmission in Africa using several malaria models driven by Institute Pierre Simon Laplace climate simulations. Results reveal that our melting scenario could moderate the simulated increase in malaria risk over East Africa, due to cooling and drying effects, cause a largest decrease in malaria transmission risk over West Africa and drive malaria emergence in southern Africa associated with a significant southward shift of the African rain-belt. We argue that the effect of such ice-sheet melting should be investigated further in future public health and agriculture climate change risk assessments.

scholarly journals Refined broad-scale sub-glacial morphology of Aurora Subglacial Basin, East Antarctica derived by an ice-dynamics-based interpolation scheme

2011 ◽  
Vol 5 (3) ◽  
pp. 551-560 ◽  
Author(s):  
J. L. Roberts ◽  
R. C. Warner ◽  
D. Young ◽  
A. Wright ◽  
T. D. van Ommen ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
East Antarctica ◽  
Geometric Constraints ◽  
Ice Thickness ◽  
Interpolation Scheme ◽  
Ice Dynamics ◽  
High Resolution Data ◽  
Physically Based ◽  
Glacial Morphology

Abstract. Ice thickness data over much of East Antarctica are sparse and irregularly distributed. This poses difficulties for reconstructing the homogeneous coverage needed to properly assess underlying sub-glacial morphology and fundamental geometric constraints on sea level rise. Here we introduce a new physically-based ice thickness interpolation scheme and apply this to existing ice thickness data in the Aurora Subglacial Basin region. The skill and robustness of the new reconstruction is demonstrated by comparison with new data from the ICECAP project. The interpolated morphology shows an extensive marine-based ice sheet, with considerably more area below sea-level than shown by prior studies. It also shows deep features connecting the coastal grounding zone with the deepest regions in the interior. This has implications for ice sheet response to a warming ocean and underscores the importance of obtaining additional high resolution data in these marginal zones for modelling ice sheet evolution.

scholarly journals Refined broad-scale sub-glacial morphology of Aurora Subglacial Basin, East Antarctica derived by an ice-dynamics-based interpolation scheme

2011 ◽  
Vol 5 (1) ◽  
pp. 655-684 ◽  
Author(s):  
J. L. Roberts ◽  
R. C. Warner ◽  
D. Young ◽  
A. Wright ◽  
T. D. van Ommen ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
East Antarctica ◽  
Geometric Constraints ◽  
Ice Thickness ◽  
Interpolation Scheme ◽  
Ice Dynamics ◽  
High Resolution Data ◽  
Physically Based ◽  
Glacial Morphology

Abstract. Ice thickness data over much of East Antarctica are sparse and irregularly distributed. This poses difficulties for reconstructing the homogeneous coverage needed to properly assess underlying sub-glacial morphology and fundamental geometric constraints on sea level rise. Here we introduce a new physically-based ice thickness interpolation scheme and apply this to existing ice thickness data in the Aurora Subglacial Basin region. The skill and robustness of the new reconstruction is demonstrated by comparison with new data from the ICECAP project. The interpolated morphology shows an extensive marine-based ice sheet, with considerably more area below sea-level than shown by prior studies. It also shows deep features connecting the coastal grounding zone with the deepest regions in the interior. This has implications for ice sheet response to a warming ocean and underscores the importance of obtaining additional high resolution data in these marginal zones for modelling ice sheet evolution.

scholarly journals Dynamic influence of pinning points on marine ice-sheet stability: a numerical study in Dronning Maud Land, East Antarctica

2016 ◽  
Vol 10 (6) ◽  
pp. 2623-2635 ◽  
Author(s):  
Lionel Favier ◽  
Frank Pattyn ◽  
Sophie Berger ◽  
Reinhard Drews
Keyword(s):  
Data Assimilation ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
East Antarctica ◽  
Ice Shelf ◽  
Ice Dynamics ◽  
Outlet Glacier ◽  
Ice Shelves ◽  
Dronning Maud Land

Abstract. The East Antarctic ice sheet is likely more stable than its West Antarctic counterpart because its bed is largely lying above sea level. However, the ice sheet in Dronning Maud Land, East Antarctica, contains marine sectors that are in contact with the ocean through overdeepened marine basins interspersed by grounded ice promontories and ice rises, pinning and stabilising the ice shelves. In this paper, we use the ice-sheet model BISICLES to investigate the effect of sub-ice-shelf melting, using a series of scenarios compliant with current values, on the ice-dynamic stability of the outlet glaciers between the Lazarev and Roi Baudouin ice shelves over the next millennium. Overall, the sub-ice-shelf melting substantially impacts the sea-level contribution. Locally, we predict a short-term rapid grounding-line retreat of the overdeepened outlet glacier Hansenbreen, which further induces the transition of the bordering ice promontories into ice rises. Furthermore, our analysis demonstrated that the onset of the marine ice-sheet retreat and subsequent promontory transition into ice rise is controlled by small pinning points, mostly uncharted in pan-Antarctic datasets. Pinning points have a twofold impact on marine ice sheets. They decrease the ice discharge by buttressing effect, and they play a crucial role in initialising marine ice sheets through data assimilation, leading to errors in ice-shelf rheology when omitted. Our results show that unpinning increases the sea-level rise by 10 %, while omitting the same pinning point in data assimilation decreases it by 10 %, but the more striking effect is in the promontory transition time, advanced by two centuries for unpinning and delayed by almost half a millennium when the pinning point is missing in data assimilation. Pinning points exert a subtle influence on ice dynamics at the kilometre scale, which calls for a better knowledge of the Antarctic margins.

scholarly journals Coupled Wave-2D Hydrodynamics Modeling at the Reno River Mouth (Italy) under Climate Change Scenarios

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1380 ◽  
Author(s):  
Maria Gabriella Gaeta ◽  
Davide Bonaldo ◽  
Achilleas G. Samaras ◽  
Sandro Carniel ◽  
Renata Archetti
Keyword(s):  
Climate Change ◽  
Open Source ◽  
Climate Changes ◽  
Adriatic Sea ◽  
Numerical Study ◽  
Numerical Models ◽  
Joint Probability ◽  
River Mouth ◽  
Climate Change Scenarios ◽  
Coupled Wave

This work presents the results of the numerical study implemented for the natural area of Lido di Spina, a touristic site along the Italian coast of the North Adriatic Sea, close to the mouth of River Reno. High-resolution simulations of nearshore dynamics are carried out under climate change conditions estimated for the site. The adopted modeling chain is based on the implementation of multiple-nested, open-source numerical models. More specifically, the coupled wave-2D hydrodynamics runs, using the open-source TELEMAC suite, are forced at the offshore boundary by waves resulting from the wave model (SWAN) simulations for the Adriatic Sea, and sea levels computed following a joint probability analysis approach. The system simulates present-day scenarios, as well as conditions reflecting the high IPCC greenhouse concentration trajectory named RCP8.5 under predicted climate changes. Selection of sea storms directed from SE (Sirocco events) and E–NE (Bora events) is performed together with Gumbel analysis, in order to define ordinary and extreme sea conditions. The numerical results are here presented in terms of local parameters such as wave breaking position, alongshore currents intensity and direction and flooded area, aiming to provide insights on how climate changes may impact hydrodynamics at a site scale. Although the wave energy intensity predicted for Sirocco events is expected to increase only slightly, modifications of the wave dynamics, current patterns, and inland flooding induced by climate changes are expected to be significant for extreme conditions, especially during Sirocco winds, with an increase in the maximum alongshore currents and in the inundated area compared to past conditions.

Emerging climate changes and the risks to the operation of building assets in the UK

2016 ◽  
Vol 14 (1) ◽  
pp. 21-35 ◽  
Author(s):  
Abdullah Alzahrani ◽  
Halim Boussabaine ◽  
Ali Nasser Alzaed
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Mitigation Strategies ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Content Type ◽  
Starting Point ◽  
Climate Change Risks ◽  
The Uk ◽  
The Impact

Purpose – The purpose of this paper is to report results from a survey on emerging climate changes and the risks to the operation of building assets in the UK. The property sector is facing major challenges as a result of projected climate change scenarios. Predictions concerning future climate change and the subsequent impact on building operations are still subject to a high degree of uncertainty. However, it is important that building stockholders consider a range of possible future risks that may influence the operation of their assets. Design/methodology/approach – The literature review and questionnaire are used to elicit and assess the likelihood of occurrence of climate change risks impacting building operations. The survey was carried out among building stockowners and professionals in the UK. Statistical methods were used to rank and compare the findings. Findings – The majority of the respondents strongly agreed that the list of risks that were elicited from the literature will have an impact on their building assets within a 0-5 years’ time horizon. It was found that the professionals were most concerned about higher energy prices and an increase in operation costs in general; they were least concerned about an electricity blackout. Research limitations/implications – This paper is limited to the UK, and regional variations are not explored. Nevertheless, the buildings’ operation risk study provides a starting point for further investigations into the emerging risks from climate change, and their impact on the operation of building stock. Future work could investigate direct mapping between climate risks and the financial value of properties. Originality/value – Findings of this paper can help professionals and building stockowners improve their understanding of climate change risks and the impact on their assets. This paper could also help these individuals to formulate appropriate adaptation and mitigation strategies.

scholarly journals Reservoir yield intercomparison of large dams in Jaguaribe Basin-CE in climate change scenarios

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Renato de Oliveira Fernandes ◽  
Cleiton da Silva Silveira ◽  
Ticiana Marinho de Carvalho Studart ◽  
Francisco de Assis de Souza Filho
Keyword(s):  
Climate Change ◽  
Climate Changes ◽  
Climate Change Scenarios ◽  
Intergovernmental Panel ◽  
Global Circulation ◽  
Global Circulation Models ◽  
Great Divergence ◽  
Rainfall Runoff Model ◽  
The Impact ◽  
Reservoir Yield

ABSTRACT Climate changes can have different impacts on water resources. Strategies to adapt to climate changes depend on impact studies. In this context, this study aimed to estimate the impact that changes in precipitation, projected by Global Circulation Models (GCMs) in the fifth report by the Intergovernmental Panel on Climate Change (IPCC-AR5) may cause on reservoir yield (Q90) of large reservoirs (Castanhão and Banabuiú), located in the Jaguaribe River Basin, Ceará. The rainfall data are from 20 GCMs using two greenhouse gas scenarios (RCP4.5 and RCP8.5). The precipitation projections were used as input data for the rainfall-runoff model (SMAP) and, after the reservoirs’ inflow generation, the reservoir yields were simulated in the AcquaNet model, for the time periods of 2040-2069 and 2070-2099. The results were analyzed and presented a great divergence, in sign (increase or decrease) and in the magnitude of change of Q90. However, most Q90 projections indicated reduction in both reservoirs, for the two periods, especially at the end of the 21th century.

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