scholarly journals An assessment of the spatial extent of polar dust using satellite thermal data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Bowen ◽  
R. F. Vincent
Keyword(s):  
Climate Models ◽  
Linear Trend ◽  
Radiative Properties ◽  
Spatial Extent ◽  
The Arctic ◽  
Dust Particles ◽  
Boreal Winter ◽  
Polar Regions ◽  
Dust Aerosols ◽  
The Antarctic

AbstractThe effect of mineral dust aerosols and subsequent deposition in polar regions has historically been underestimated in climate models. Dust aerosols increase melt rates by reducing surface albedo and modifying atmospheric radiative properties. In this study 127,413 satellite images covering the Arctic and Antarctic from 2007 to 2019 were assessed for dust content using thermal infrared wavelengths. The results show a strong linear trend in which the relative spatial extent of dust (RSED) increased annually by 0.31% in the Arctic (8.5% to 12.1%) and 0.19% in the Antarctic (5.2% to 7.5%). Seasonally, the maximum aggregated average RSED occurred in the Arctic during boreal winter (11.2%), while the Antarctic peaked in austral spring (9.5%). Maximum RSED rates occurred in boreal winter/austral summer (Dec–Jan–Feb) for both polar regions. The data suggests that finer dust particles are more efficiently distributed by aeolian processes leading to higher RSED values that are not necessarily reflective of polar dust loading models.

scholarly journals Assessment of sea ice simulations in the CMIP5 models

2015 ◽  
Vol 9 (1) ◽  
pp. 399-409 ◽  
Author(s):  
Q. Shu ◽  
Z. Song ◽  
F. Qiao
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Linear Trend ◽  
Ocean Modeling ◽  
The Arctic ◽  
Cmip5 Models ◽  
Output Data ◽  
Sea Ice Extent ◽  
The Antarctic ◽  
Assimilation System

Abstract. The historical simulations of sea ice during 1979 to 2005 by the Coupled Model Intercomparison Project Phase 5 (CMIP5) are compared with satellite observations, Global Ice-Ocean Modeling and Assimilation System (GIOMAS) output data and Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) output data in this study. Forty-nine models, almost all of the CMIP5 climate models and earth system models with historical simulation, are used. For the Antarctic, multi-model ensemble mean (MME) results can give good climatology of sea ice extent (SIE), but the linear trend is incorrect. The linear trend of satellite-observed Antarctic SIE is 1.29 (±0.57) × 105 km2 decade−1; only about 1/7 CMIP5 models show increasing trends, and the linear trend of CMIP5 MME is negative with the value of −3.36 (±0.15) × 105 km2 decade−1. For the Arctic, both climatology and linear trend are better reproduced. Sea ice volume (SIV) is also evaluated in this study, and this is a first attempt to evaluate the SIV in all CMIP5 models. Compared with the GIOMAS and PIOMAS data, the SIV values in both the Antarctic and the Arctic are too small, especially for the Antarctic in spring and winter. The GIOMAS Antarctic SIV in September is 19.1 × 103 km3, while the corresponding Antarctic SIV of CMIP5 MME is 13.0 × 103 km3 (almost 32% less). The Arctic SIV of CMIP5 in April is 27.1 × 103 km3, which is also less than that from PIOMAS SIV (29.5 × 103 km3). This means that the sea ice thickness simulated in CMIP5 is too thin, although the SIE is fairly well simulated.

scholarly journals Uncertainties and assessments of chemistry-climate models of the stratosphere

2002 ◽  
Vol 2 (4) ◽  
pp. 1035-1096 ◽  
Author(s):  
J. Austin ◽  
D. Shindell ◽  
S. R. Beagley ◽  
C. Brühl ◽  
M. Dameris ◽  
...  
Keyword(s):  
Climate Models ◽  
Wave Drag ◽  
Horizontal Resolution ◽  
The Arctic ◽  
Cold Bias ◽  
Polar Regions ◽  
Wide Range ◽  
Antarctic Ozone ◽  
Stratospheric Clouds ◽  
The Antarctic

Abstract. In recent years a number of chemistry-climate models have been developed with an emphasis on the stratosphere. Such models cover a wide range of timescales of integration and vary considerably in complexity. The results of specific diagnostics are here analysed to examine the differences amongst individual models and observations, to assess the consistency of model predictions, with a particular focus on polar ozone. For example, many models indicate a significant cold bias in high latitudes, the 'cold pole problem', particularly in the southern hemisphere during winter and spring. This is related to wave propagation from the troposphere which can be improved by improving model horizontal resolution and with the use of non-orographic gravity wave drag. As a result of the widely differing modeled polar temperatures, different amounts of polar stratospheric clouds are simulated which in turn result in varying ozone values in the models. The results are also compared to determine the possible future behaviour of ozone, with an emphasis on the polar regions and mid-latitudes. All models predict eventual ozone recovery, but give a range of results concerning its timing and extent. Differences in the simulation of gravity waves and planetary waves as well as model resolution are likely major sources of uncertainty for this issue. In the Antarctic, the ozone hole has probably reached almost its deepest although the vertical and horizontal extent of depletion may increase slightly further over the next few years. According to the model results, Antarctic ozone recovery could begin any year within the range 2001 to 2008. For the Arctic, most models indicate that small ozone losses may continue for a few more years and that recovery could begin any year within the range 2004 to 2019. The start of ozone recovery in the Arctic is therefore expected to appear later than in the Antarctic in most models. Further, interannual variability will tend to mask the signal for longer in the Arctic than in the Antarctic, delaying still further the date at which ozone recovery may be said to have started. In the longer term, the model results suggest that full recovery of ozone to 1980 levels is not expected in the Antarctic until about the year 2050. Earlier recovery to 1980 levels may be possible in the Arctic, but model differences are too large compared with the simulated changes to obtain a reliable date.

scholarly journals Uncertainties and assessments of chemistry-climate models of the stratosphere

2003 ◽  
Vol 3 (1) ◽  
pp. 1-27 ◽  
Author(s):  
J. Austin ◽  
D. Shindell ◽  
S. R. Beagley ◽  
C. Brühl ◽  
M. Dameris ◽  
...  
Keyword(s):  
Climate Models ◽  
Wave Drag ◽  
Horizontal Resolution ◽  
The Arctic ◽  
Cold Bias ◽  
Polar Regions ◽  
Wide Range ◽  
Antarctic Ozone ◽  
Stratospheric Clouds ◽  
The Antarctic

Abstract. In recent years a number of chemistry-climate models have been developed with an emphasis on the stratosphere. Such models cover a wide range of time scales of integration and vary considerably in complexity. The results of specific diagnostics are here analysed to examine the differences amongst individual models and observations, to assess the consistency of model predictions, with a particular focus on polar ozone. For example, many models indicate a significant cold bias in high latitudes, the "cold pole problem", particularly in the southern hemisphere during winter and spring. This is related to wave propagation from the troposphere which can be improved by improving model horizontal resolution and with the use of non-orographic gravity wave drag. As a result of the widely differing modelled polar temperatures, different amounts of polar stratospheric clouds are simulated which in turn result in varying ozone values in the models. The results are also compared to determine the possible future behaviour of ozone, with an emphasis on the polar regions and mid-latitudes. All models predict eventual ozone recovery, but give a range of results concerning its timing and extent. Differences in the simulation of gravity waves and planetary waves as well as model resolution are likely major sources of uncertainty for this issue. In the Antarctic, the ozone hole has probably reached almost its deepest although the vertical and horizontal extent of depletion may increase slightly further over the next few years. According to the model results, Antarctic ozone recovery could begin any year within the range 2001 to 2008. The limited number of models which have been integrated sufficiently far indicate that full recovery of ozone to 1980 levels may not occur in the Antarctic until about the year 2050. For the Arctic, most models indicate that small ozone losses may continue for a few more years and that recovery could begin any year within the range 2004 to 2019. The start of ozone recovery in the Arctic is therefore expected to appear later than in the Antarctic. Further, interannual variability will tend to mask the signal for longer than in the Antarctic, delaying still further the date at which ozone recovery may be said to have started. Because of this inherent variability of the system, the decadal evolution of Arctic ozone will not necessarily be a direct response to external forcing.

Evaluation of interannual variability of Arctic and Antarctic ozone loss since 1989

2021 ◽  
Author(s):  
Florence Goutail ◽  
Andrea Pazmino ◽  
Jean-Pierre Pommereau ◽  
Franck Lefevre ◽  
Sophie Godin-Beekmann ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Climate Models ◽  
Average Rate ◽  
Linear Trend ◽  
The Arctic ◽  
Polar Regions ◽  
Mean Values ◽  
Ozone Loss ◽  
Ozone Destruction ◽  
Daily Rate

<p>Ozone depletion over Polar Regions is monitored each year by satellite and ground-based instruments. The first signs of healing of the ozone layer linked to the decrease of ozone destructive substances (ODSs) were observed in Antarctica using different metrics (ozone mean values, ozone mass deficit, area of the ozone hole) and simple or sophisticated models. Chemistry climate models predict that climate change will not affect expected ozone recovery over Antarctica but will accelerate recovery in the Arctic due to the possible enhancement of the Brewer Dobson circulation. However, ozone loss observations by SAOZ UV-Vis spectrometers do not show a clear sign of recovery in the latter region. In addition, a record of 38% ozone loss in 2010/2011 and 2019/2020 was estimated.</p><p>In this study, the vortex-averaged ozone loss in the last three decades will be evaluated for both Polar Regions using the passive ozone tracer of two chemical transport models (REPROBUS and SLIMCAT CTMs) and total ozone observations from SAOZ and satellite observations (IASI/METOP and Multi-Sensor Reanalysis (MSR-2)).</p><p>The tracer method allows us to determine the evolution of the daily rate of ozone destruction, and the amplitude of the cumulative loss at the end of the winter. The cumulative ozone destruction in the Artic varies between 0-10% in relatively warm winters with short vortex duration to up to 25-38% in colder winters with longer vortex persistence, while in Antarctica it is mostly stable, around 50%.</p><p>Interannual variability of 10-days average rate will be analyzed and compared between both hemispheres as well as the timing to reach different thresholds of absolute ozone loss values. Finally, linear trend of ozone loss and temperature since 2000 will be estimated in both Polar Regions in order to evaluate possible ozone recovery.</p>

scholarly journals Evolution in the cold

2000 ◽  
Vol 12 (3) ◽  
pp. 257-257 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Evolutionary Biology ◽  
Antarctic Fish ◽  
The Arctic ◽  
Polar Regions ◽  
Evolutionary Studies ◽  
Adaptive Radiations ◽  
The Antarctic ◽  
The Impact ◽  
Insight Into

Theodosius Dobzhansky once remarked that nothing in biology makes sense other than in the light of evolution, thereby emphasising the central role of evolutionary studies in providing the theoretical context for all of biology. It is perhaps surprising then that evolutionary biology has played such a small role to date in Antarctic science. This is particularly so when it is recognised that the polar regions provide us with an unrivalled laboratory within which to undertake evolutionary studies. The Antarctic exhibits one of the classic examples of a resistance adaptation (antifreeze peptides and glycopeptides, first described from Antarctic fish), and provides textbook examples of adaptive radiations (for example amphipod crustaceans and notothenioid fish). The land is still largely in the grip of major glaciation, and the once rich terrestrial floras and faunas of Cenozoic Gondwana are now highly depauperate and confined to relatively small patches of habitat, often extremely isolated from other such patches. Unlike the Arctic, where organisms are returning to newly deglaciated land from refugia on the continental landmasses to the south, recolonization of Antarctica has had to take place by the dispersal of propagules over vast distances. Antarctica thus offers an insight into the evolutionary responses of terrestrial floras and faunas to extreme climatic change unrivalled in the world. The sea forms a strong contrast to the land in that here the impact of climate appears to have been less severe, at least in as much as few elements of the fauna show convincing signs of having been completely eradicated.

scholarly journals BRICS in polar regions: Brazil’s interests and prospects

2020 ◽  
Vol 13 (3) ◽  
pp. 326-340
Author(s):  
Paulo Borba Casella ◽  
◽  
Maria Lagutina ◽  
Arthur Roberto Capella Giannattasio ◽  
◽  
...  
Keyword(s):  
Legal Regulation ◽  
The Arctic ◽  
Polar Regions ◽  
Arctic Council ◽  
Public Power ◽  
Promising Tool ◽  
Antarctic Treaty ◽  
International Power ◽  
Global Affairs ◽  
The Antarctic

The current international legal regulation of the Arctic and Antarctica was organized during the second half of the XX century to establish an international public power over the two regions, the Arctic Council (AC) and the Antarctic Treaty System (ATS), which is characterized by Euro-American dominance. However, the rise of emerging countries at the beginning of the XXI century suggests a progressive redefinition of the structural balance of international power in favor of states not traditionally perceived as European and Western. This article examines the role of Brazil within the AC and the ATS to address various polar issues, even institutional ones. As a responsible country in the area of cooperation in science and technology in the oceans and polar regions in BRICS, Brazil appeals to its rich experience in Antarctica and declares its interest in joining the Arctic cooperation. For Brazil, participation in polar cooperation is a way to increase its role in global affairs and BRICS as a negotiating platform. It is seen in this context as a promising tool to achieve this goal. This article highlights new paths in the research agenda concerning interests and prospects of Brazilian agency in the polar regions.

scholarly journals Impact of ocean circulation on regional polar climate simulations using the Arctic Region Climate System Model

1997 ◽  
Vol 25 ◽  
pp. 203-207 ◽  
Author(s):  
David A. Bailey ◽  
Amanda H. Lynch ◽  
Katherine S. Hedström
Keyword(s):  
Sea Ice ◽  
Mixed Layer ◽  
Climate Models ◽  
Regional Climate ◽  
The Arctic ◽  
Water Runoff ◽  
Polar Regions ◽  
Ice Dynamics ◽  
Climate System Model ◽  
Ice Model

Global climate models have pointed to the polar regions as very sensitive areas in response to climate change. However, these models often do not contain representations of processes peculiar to the polar regions such as dynamic sea ice, permafrost, and Arctic stratus clouds. Further, global models do not have the resolution necessary to model accurately many of the important processes and feedbacks. Thus, there is a need for regional climate models of higher resolution. Our such model (ARCSy M) has been developed by A. Lynch and W. Chapman. This model incorporates the NCAR Regional Climate Model (RegCM2) with the addition of Flato–Hibler cavitating fluid sea-ice dynamics and Parkinson–Washington ice thermodynamic formulation. Recently work has been conducted to couple a mixed-layer ocean to the atmosphere–ice model, and a three-dimensional (3-D) dynamical ocean model, in this case the S-Coordinate Primitive Equation Model (SPEM), to the ice model. Simulations including oceanic circulation will allow investigations of the feedbacks involved in fresh-water runoff from sea-ice melt and sea-ice transport. Further, it is shown that the definition of the mixed-layer depth has significant impact on ice thermodynamics.

The Polar Regions and the Development of International Law: Contemporary Reflections and Twenty-First Century Challenges

2013 ◽  
Vol 5 (1) ◽  
pp. 233-251 ◽  
Author(s):  
Donald R. Rothwell
Keyword(s):  
International Law ◽  
First Century ◽  
The Arctic ◽  
Polar Regions ◽  
Foundational Research ◽  
Twenty First Century ◽  
Legal Frameworks ◽  
Global Affairs ◽  
The Antarctic ◽  
The Impact

Abstract The polar regions are increasingly coming to the forefront of global affairs in ways that are beginning to approach the prominence given to the polar regions during the ‘heroic era’ of exploration at the beginning of the twentieth century. This contemporary focus is, however, very much upon governance and the capacity of the existing and future legal frameworks to govern the Antarctic and Arctic effectively. This article revisits foundational research undertaken in 1992–1993 and reassesses the impact of the polar regions upon the development of international law. Particular attention is given to environmental management, living and nonliving resource management, the regulation and management of maritime areas, and governance mechanisms and frameworks. The article seeks to critically assess whether the existing legal frameworks that operate in Antarctica and the Arctic are capable of dealing with their increasing globalisation, or whether there will be a need for new legal and governance regimes to be developed to address twenty-first century challenges.

Polar tourism regulation strategies: controlling visitors through codes of conduct and legislation

Polar Record ◽  
1997 ◽  
Vol 33 (184) ◽  
pp. 13-20 ◽  
Author(s):  
Margaret E. Johnston
Keyword(s):  
Codes Of Conduct ◽  
Specific Area ◽  
Tourism Industry ◽  
The Arctic ◽  
Polar Regions ◽  
Regulation Strategies ◽  
Area Of Concern ◽  
Tourist Behaviour ◽  
The Antarctic ◽  
Further Development

AbstractControlling visitor impacts in polar regions continues to be important in both the Antarctic and Arctic. Concerns relate to impacts on the physical environment, cultural heritage, and host communities or scientific bases, as well as a recognition that safety and liability are major issues for governments, commercial operators, and local populations. Strategies for controlling tourists include visitor and operator codes and formal legislation. This paper summarises several approaches to visitor regulation in polar regions in order to illustrate the ways in which concerns about tourist impacts are being addressed. Similar issues arise throughout the polar regions, although in some places a particular emphasis might indicate a specific area of concern for a community, region, nation, or segment of the tourism industry. While a comprehensive strategy might be appropriate in many respects in the Arctic, it is also important to acknowledge the significance of more specific concerns. This paper first describes regulation of tourist behaviour and considers general issues of strategy effectiveness. Then it examines the approaches to visitor regulation used in the Antarctic and on S valbard as examples that may be of use in the further development of strategies in the Arctic. The paper then discusses an evolving strategy for control in the Northwest Territories, Canada. This strategy differs from these other approaches in that it targets a specific segment of the visitor population: those undertaking adventure expeditions.

scholarly journals Inter-hemispheric seasonal comparison of Polar Amplification using radiative forcing of quadrupling CO<sub>2</sub> experiment

2019 ◽  
Author(s):  
Fernanda Casagrande ◽  
Ronald Buss de Souza ◽  
Paulo Nobre ◽  
Andre Lanfer Marquez
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
Radiative Forcing ◽  
Climate Models ◽  
Initial Conditions ◽  
The Arctic ◽  
Climate Simulation ◽  
Polar Regions ◽  
High Latitudes ◽  
Polar Amplification

Abstract. The numerical climate simulation from Brazilian Earth System Model (BESM) are used here to investigate the response of Polar Regions to a forced increase of CO2 (Abrupt-4xCO2) and compared with Coupled Model Intercomparison Project 5 (CMIP5) simulations. Polar Regions are described as the most climatically sensitive areas of the globe, with an enhanced warming occurring during the cold seasons. The asymmetry between the two poles is related to the thermal inertia and the coupled ocean atmosphere processes involved. While in the northern high latitudes the amplified warming signal is associated to a positive snow and sea ice albedo feedback, for southern high latitudes the warming is related to a combination of ozone depletion and changes in the winds pattern. The numerical experiments conducted here demonstrated a very clear evidence of seasonality in the polar amplification response. In winter, for the northern high latitudes (southern high latitudes) the range of simulated polar warming varied from 15 K to 30 K (2.6 K to 10 K). In summer, for northern high latitudes (southern high latitudes) the simulated warming varies from 3 K to 15 K (3 K to 7 K). The vertical profiles of air temperature indicated stronger warming at surface, particularly for the Arctic region, suggesting that the albedo-sea ice feedback overlaps with the warming caused by meridional transport of heat in atmosphere. The latitude of the maximum warming was inversely correlated with changes in the sea ice within the model’s control run. Three climate models were identified as having high polar amplification for cold season in both poles: MIROC-ESM, BESM-OA V2.5 and GFDL-ESM2M. We suggest that the large BIAS found between models can be related to the differences in each model to represent the feedback process and also as a consequence of the distinct sea ice initial conditions of each model. The polar amplification phenomenon has been observed previously and is expected to become stronger in coming decades. The consequences for the atmospheric and ocean circulation are still subject to intense debate in the scientific community.

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