scholarly journals Abundance and Biodiversity of Top Predators - Seabirds and Marine Mammals - in Antarctic Seas

2020 ◽  
Vol 3 (3) ◽  
Keyword(s):  
Sea Level ◽  
Marine Mammals ◽  
Weddell Sea ◽  
Amundsen Sea ◽  
Top Predators ◽  
Very High

This article concerns the comparison of data collected in different Antarctic seas by the same team, same platform (mainly from the bridge of icebreaking RV Polarstern, 18 m above sea level), and thus the same methodology. Drastic differences were noted, from very high numbers in the Weddell Sea to very low ones in the Amundsen Sea. Biodiversity was low, as reflected by low numbers of species, a few of them representing the vast majority in numbers of individuals: between 85% and 95% of the total.

scholarly journals Comparing ice discharge through West Antarctic Gateways: Weddell vs. Amundsen Sea warming

2015 ◽  
Vol 9 (2) ◽  
pp. 1705-1733 ◽  
Author(s):  
M. A. Martin ◽  
A. Levermann ◽  
R. Winkelmann
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
Back Stress ◽  
Step Function ◽  
Ocean Warming ◽  
Weddell Sea ◽  
Amundsen Sea ◽  
Function Type ◽  
West Antarctic ◽  
Grounding Line

Abstract. Future changes in Antarctic ice discharge will be largely controlled by the fate of the floating ice shelves, which exert a back-stress onto Antarctica's marine outlet glaciers. Ice loss in response to warming of the Amundsen Sea has been observed and investigated as a potential trigger for the marine ice-sheet instability. Recent observations and simulations suggest that the Amundsen Sea Sector might already be unstable which would have strong implications for global sea-level rise. At the same time, regional ocean projections show much stronger warm-water intrusion into ice-shelf cavities in the Weddell Sea compared to the observed Amundsen warming. Here we present results of numerical ice sheet modelling with the Parallel Ice Sheet Model (PISM) which show that idealized, step-function type ocean warming in the Weddell Sea leads to more immediate ice discharge with a higher sensitivity to small warming levels than the same warming in the Amundsen Sea. This is consistent with the specific combination of bedrock and ice topography in the Weddell Sea Sector which results in an ice sheet close to floatation. In response to even slight ocean warming, ice loss increases rapidly, peaks and declines within one century. While the cumulative ice loss in the Amundsen Sea Sector is of similar magnitude after five centuries of continued warming, ice loss increases at a slower pace and only for significantly higher warming levels. Although there is more marine ice stored above sea level in close vicinity of the grounding line compared to the Weddell Sea Sector, the ice sheet is farther from floatation and the grounding line initially retreats more slowly.

Antarctic Peninsula Regional Circulation and its Impact on the Surface Melt of Larsen C Ice Shelf

2021 ◽  
pp. 1-38
Author(s):  
Chongran Zhang ◽  
Jing Zhang ◽  
Qigang Wu
Keyword(s):  
Time Series ◽  
Surface Temperature ◽  
Sea Level ◽  
Antarctic Peninsula ◽  
Weddell Sea ◽  
Amundsen Sea ◽  
Budget Analysis ◽  
Regional Circulation ◽  
Mode 2 ◽  
Surface Melt

AbstractEnhanced surface melt over the ice shelves of the Antarctic Peninsula (AP) is one of the precursors to their collapse, which can be proceeded by accelerated ground glacier flow and increased contribution to sea level rise. With the collapse of Larsen A and B, and the major 2017 calving event from Larsen C, whether Larsen C is bound for a similar fate has received increasing attention. Here, the interannual variation of regional circulation over the AP region is studied using the Empirical Orthogonal Function (EOF) / Principal Component (PC) analysis on the sea level pressure of ERA5 reanalysis. The EOF modes capture the variations of depth, location and extent of Amundsen Sea Low and Weddell Sea Low in each season. Statistically significant positive correlations exist between Larsen C surface temperature and the PC time series of EOF mode 1 in winter and spring through northerly/northwesterly wind anomalies west of the AP. The PC time series of EOF mode 2 is negatively correlated with Larsen C surface temperature in autumn and summer and surface melt in summer, all due to southerly wind anomalies east of the AP. Surface energy budget analysis associated with EOF mode 2 shows that downwelling longwave radiation over Larsen C is negatively statistically significantly, correlated with EOF mode 2 and is the major atmospheric forcing regulating the variation of Larsen C surface melt. Positively enhanced EOF mode 2 since 2004 is responsible for the recent cooling and decline of surface melt over Larsen C.

scholarly journals Seasonal variation of the Antarctic Slope Front occurence and position estimated from an interpolated hydrographic climatology

2021 ◽  
Author(s):  
Etienne Pauthenet ◽  
Jean-Baptiste Sallée ◽  
Sunke Schmidtko ◽  
David Nerini
Keyword(s):  
Temperature Gradient ◽  
Marine Mammals ◽  
Mapping Method ◽  
Shelf Break ◽  
Weddell Sea ◽  
Contour Method ◽  
Amundsen Sea ◽  
Near Surface ◽  
Antarctic Slope Current ◽  
The Antarctic

AbstractThe Antarctic Slope Front (ASF) is a fundamental feature of the subpolar Southern Ocean that is still poorly observed. In this study we build a statistical climatology of the temperature and salinity fields of the upper 380 m of the Antarctic margin. We use a comprehensive compilation of observational datasets including the profiles gathered by instrumented marine mammals. The mapping method consists first of a decomposition in vertical modes of the combined temperature and salinity profiles. Then the resulting principal components are optimally interpolated on a regular grid and the monthly climatological profiles are reconstructed, providing a physically plausible representation of the ocean. The ASF is located with a contour method and a gradient method applied on the temperature field, two complementary approaches that provide a complete view of the ASF structure. The front extends from the Amundsen Sea to the eastern Weddell Sea and closely tracks the continental shelf break. It is associated with a sharp temperature gradient that is stronger in Winter and weaker in Summer. The emergence of the front in the Amundsen and Bellingshausen sector appears seasonally variable (slightly more westward in Winter than in Summer). The investigation of the density gradients across the shelf break indicates a Winter slowdown of the baroclinic component of the Antarctic Slope Current at the near-surface, in contrast with the seasonal variability of the temperature gradient.

Energy Situation and Energy-Related Environment Issues of Pacific Island Countries

1991 ◽  
Vol 2 (4) ◽  
pp. 339-347
Author(s):  
Suliana Siwatibau
Keyword(s):  
Economic Growth ◽  
Sea Level Rise ◽  
Sea Level ◽  
Pacific Islands ◽  
Petroleum Products ◽  
Pacific Island ◽  
Energy Environment ◽  
Over Exploitation ◽  
Pacific Island Nations ◽  
Very High

Pacific Islands have experienced low economic growth during the 1980s, and face significant energy problems. Petroleum products are imported at very high prices and biofuel use often leads to resource over-exploitation. However, perhaps the most basic energy-environment concern is the potential for sea level rise. Some Pacific Island nations would vanish altogether, while others would lose their most productive areas.

scholarly journals Potential source regions of biogenic aerosol number concentration apportioning at King George Island, Antarctic Peninsula

2010 ◽  
Vol 22 (5) ◽  
pp. 580-588 ◽  
Author(s):  
Alexandre S. Alencar ◽  
Heitor Evangelista ◽  
Elaine A. Dos Santos ◽  
Sergio M. Correa ◽  
Myriam Khodri ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Number Concentration ◽  
Weddell Sea ◽  
South Shetland Islands ◽  
Wide Field ◽  
King George Island ◽  
Amundsen Sea ◽  
Atlantic Sector ◽  
Aerosol Number Concentration ◽  
Argentinean Shelf

AbstractNowadays it is well accepted that background aerosols in the boundary layer over remote oceans are of marine origin and not aged continental. Particularly in the Atlantic sector of the Southern Ocean at least four main important regions exhibit significant ocean primary productivity. They are the Bellingshausen–Amundsen Sea, the Weddell Sea, the southern Argentinean shelf and the southern Chilean coast. In this work, we have combined ground-based continuous atmospheric sampling of aerosol number concentration (ANC), over-sea dimethyl sulphide (DMS) measurements, chlorophyll a (chl a) concentration provided by Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite images, in situ meteorological data and monthly regional NCEP-NCAR re-analysis wind fields in order to investigate the relative contribution of each of the above regions to the apportionment of the ANC at King George Island (KGI), South Shetland Islands. Our results suggest that, at least during the period from September 1998–December 1999, the southern Argentinean shelf acted as the main contributor to the ANC measured in KGI.

scholarly journals Development of Tools for Coastal Management in Google Earth 2 Engine: Uncertainty Bathtub Model and Bruun Rule

2021 ◽  
Author(s):  
Lucas Terres de Lima ◽  
Sandra Fernández-Fernández ◽  
João Francisco Gonçalves ◽  
Luiz Magalhães Filho ◽  
Cristina Bernardes
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Management ◽  
Google Earth ◽  
Environmental Data ◽  
Bathymetric Data ◽  
Bruun Rule ◽  
Source Models ◽  
Very High ◽  
Bathtub Model

Sea-level rise is a problem increasingly affecting coastal areas worldwide. The existence 15 of Free and Open-Source Models to estimate the sea-level impact can contribute to better coastal 16 management. This study aims to develop and to validate two different models to predict the 17 sea-level rise impact supported by Google Earth Engine (GEE) – a cloud-based platform for plan-18 etary-scale environmental data analysis. The first model is a Bathtub Model based on the uncer-19 tainty of projections of the Sea-level Rise Impact Module of TerrSet - Geospatial Monitoring and 20 Modeling System software. The validation process performed in the Rio Grande do Sul coastal 21 plain (S Brazil) resulted in correlations from 0.75 to 1.00. The second model uses Bruun Rule for-22 mula implemented in GEE and is capable to determine the coastline retreat of a profile through the 23 creation of a simple vector line from topo-bathymetric data. The model shows a very high correla-24 tion (0.97) with a classical Bruun Rule study performed in Aveiro coast (NW Portugal). The GEE 25 platform seems to be an important tool for coastal management. The models developed have been 26 openly shared, enabling the continuous improvement of the code by the scientific community.

scholarly journals ASSESSMENT OF SUSCEPTIBILITY TO SΕA-LΕVEL RISE IN THE COASTAL AREA OF PIERIA PREFECTURE

2017 ◽  
Vol 50 (3) ◽  
pp. 1721
Author(s):  
A. Mavromatidi ◽  
E. Karymbalis
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Accretion Rate ◽  
Vulnerability Index ◽  
Coastal Areas ◽  
Tidal Range ◽  
Coastal Vulnerability Index ◽  
Economic Significance ◽  
Very High

Tourism development in Greece has led to increasing pressure on coastal areas, which makes the study of sensitive coastal areas essential, in order to find appropriate solutions for their shielding. The aim of this study is an estimation of the effects of an anticipated sea level rise for the touristically developed part of Pieria Prefecture, which includes the settlements Paralia, Skala of Katerini, Olympic Beach, Korinos Beach and extends north to the area of the Kitrous saltworks and south to the mouth of Mavroneri river. Therefore the Coastal Vulnerability Index (CVI) is applied, in an attempt to determine the susceptible parts to the potential sea level rise. CVI depends on the following parameters: (a) coastal geomorphology, (b) coastal slope, (c) shoreline erosion/accretion rate, (d) relative sea-level rise fluctuations, (e) mean tidal range and (f) mean significant wave height. The classification of the coast, which is of particular socio-economic significance since it hosts urbanized areas, into five CVI classes (from very low vulnerability to very high vulnerability), showed that 43.6% of the entire coastline is of very high vulnerability. 

scholarly journals Sea ice drift in the Southern Ocean: Regional patterns, variability, and trends

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Ron Kwok ◽  
Shirley S. Pang ◽  
Sahra Kacimi
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Sea Level ◽  
Ice Cover ◽  
The Arctic ◽  
Positive Trend ◽  
Amundsen Sea ◽  
Regional Patterns ◽  
Ice Drift ◽  
Sea Ice Drift

Understanding long-term changes in large-scale sea ice drift in the Southern Ocean is of considerable interest given its contribution to ice extent, to ice production in open waters, with associated dense water formation and heat flux to the atmosphere, and thus to the climate system. In this paper, we examine the trends and variability of this ice drift in a 34-year record (1982–2015) derived from satellite observations. Uncertainties in drift (~3 to 4 km day–1) were assessed with higher resolution observations. In a linear model, drift speeds were ~1.4% of the geostrophic wind from reanalyzed sea-level pressure, nearly 50% higher than that of the Arctic. This result suggests an ice cover in the Southern Ocean that is thinner, weaker, and less compact. Geostrophic winds explained all but ~40% of the variance in ice drift. Three spatially distinct drift patterns were shown to be controlled by the location and depth of atmospheric lows centered over the Amundsen, Riiser-Larsen, and Davis seas. Positively correlated changes in sea-level pressures at the three centers (up to 0.64) suggest correlated changes in the wind-driven drift patterns. Seasonal trends in ice edge are linked to trends in meridional winds and also to on-ice/off-ice trends in zonal winds, due to zonal asymmetry of the Antarctic ice cover. Sea ice area export at flux gates that parallel the 1000-m isobath were extended to cover the 34-year record. Interannual variability in ice export in the Ross and Weddell seas linked to the depth and location of the Amundsen Sea and Riiser-Larsen Sea lows to their east. Compared to shorter records, where there was a significant positive trend in Ross Sea ice area flux, the longer 34-year trends of outflow from both seas are now statistically insignificant.

3. Evidence for climate change

2014 ◽  
pp. 29-45
Author(s):  
Mark Maslin
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Greenhouse Gases ◽  
Sea Level ◽  
Arctic Sea Ice ◽  
Weather Patterns ◽  
Recent Climate ◽  
Arctic Sea ◽  
Global Sea Level ◽  
Very High

‘Evidence for climate change’ considers both past and recent climate change through changes in temperature, precipitation, and relative global sea level to show that significant changes in climate have been recorded. These include a 0.85°Celsius (C) increase in average global temperatures over the last 150 years, sea-level rise of over 20 cm, significant shifts in the seasonality and intensities of precipitation, changing weather patterns, and significant retreat of Arctic sea ice and nearly all continental glaciers. The IPCC 2013 report states that the evidence for global warming is unequivocal and that there is very high confidence that this warming is due to human emissions of greenhouse gases.

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