scholarly journals MONITORING OF THE NELLA FJORD WATER-ICE ECOSYSTEM (PRUDS BAY, EAST ANTARCTIC): SEASON RAE-65

2020 ◽  
Vol 48 (2) ◽  
pp. 163-165
Author(s):  
I. A. Melnikov
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
East Antarctica ◽  
Water Ice ◽  
Project Assessment ◽  
Antarctic Sea Ice ◽  
Antarctic Expedition ◽  
Russian Antarctic Expedition ◽  
The Antarctic

During the seasonal work of the Russian Antarctic expedition (RAE-65), the monitoring of the water-ice ecological system was conducted in the Nella fjord (Prude Bay, East Antarctica). This monitoring is conducted annually since the IPY in 2007 in frames of the project “Assessment of the ecology of the Antarctic sea ice zone” (“Krial”) (Melnikov, 2020). The purpose of the monitoring is the assessment of the role of water-ice biota in global biosphere processes in the Southern Ocean.

scholarly journals MONITORING OF THE WATER-ICE ECOSYSTEM IN THE ANTARCTIC COASTAL AREA ON MATERIALS OF THE RAE-64

2019 ◽  
Vol 47 (1) ◽  
pp. 223-224
Author(s):  
I.A. Melnikov
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Coastal Area ◽  
International Polar Year ◽  
Water Ice ◽  
Antarctic Expedition ◽  
Russian Antarctic Expedition ◽  
International Polar ◽  
The Antarctic

During the seasonal work of the Russian Antarctic expedition (RAE-64) in the Nella fjord at the continental station “Progress” (Prydz Bay, Eastern Antarctica), the monitoring of the water-ice ecological system has been carried out here annually since the International polar year (2007). The purpose of monitoring is to show the role of sea ice biota in the global biosphere processes of the Southern ocean.

Last Glacial Maximum Antarctic sea ice linked with global mean ocean temperature: evidence from PMIP3, PMIP4 and MIROC-4m simulations

2021 ◽  
Author(s):  
Tristan Vadsaria ◽  
Sam Sherriff-Tadano ◽  
Ayako Abe-Ouchi ◽  
Takashi Obase ◽  
Wing-Le Chan ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Last Glacial Maximum ◽  
Ocean Circulation ◽  
Glacial Maximum ◽  
Ocean Temperature ◽  
Sea Ice Extent ◽  
Last Glacial ◽  
Antarctic Sea Ice ◽  
The Antarctic

<p>Southern Ocean sea ice and oceanic fronts are known to play an important role on the climate system, carbon cycles, bottom ocean circulation, and Antarctic ice sheet. However, many models of the previous Past-climate Model Intercomparison Project (PMIP) underestimated sea-ice extent (SIE) for the Last Glacial Maximum (LGM)(Roche et al., 2012; Marzocchi and Jensen, 2017), mainly because of surface bias (Flato et al., 2013) that may have an impact on mean ocean temperature (MOT). Indeed, recent studies further suggest an important link between Southern Ocean sea ice and mean ocean temperature (Ferrari et al., 2014; Bereiter et al., 2018 among others). Misrepresent the Antarctic sea-ice extent could highly impact deep ocean circulation, the heat transport and thus the MOT. In this study, we will stress the relationship between the distribution of Antarctic sea-ice extent and the MOT through the analysis of the PMIP3 and PMIP4 exercise and by using a set of MIROC models. To date, the latest version of MIROC improve its representation of the LGM Antarctic sea-ice extent, affecting the deep circulation and the MOT distribution (Sherriff-Tadano et al., under review).</p><p>Our results show that available PMIP4 models have an overall improvement in term of LGM sea-ice extent compared to PMIP3, associated to colder deep and bottom ocean temperature. Focusing on MIROC (4m) models, we show that models accounting for Southern Ocean sea-surface temperature (SST) bias correction reproduce an Antarctic sea-ice extent, 2D-distribution, and seasonal amplitude in good agreement with proxy-based data. Finally, using PMIP-MIROC analyze, we show that it exists a relationship between the maximum SIE and the MOT, modulated by the Antarctic intermediate and bottom waters.</p>

scholarly journals Impacts of Interactive Stratospheric Chemistry on Antarctic and Southern Ocean Climate Change in the Goddard Earth Observing System, Version 5 (GEOS-5)

2016 ◽  
Vol 29 (9) ◽  
pp. 3199-3218 ◽  
Author(s):  
Feng Li ◽  
Yury V. Vikhliaev ◽  
Paul A. Newman ◽  
Steven Pawson ◽  
Judith Perlwitz ◽  
...  
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
Sea Ice ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Meridional Overturning Circulation ◽  
Stratospheric Chemistry ◽  
Earth Observing System ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract Stratospheric ozone depletion plays a major role in driving climate change in the Southern Hemisphere. To date, many climate models prescribe the stratospheric ozone layer’s evolution using monthly and zonally averaged ozone fields. However, the prescribed ozone underestimates Antarctic ozone depletion and lacks zonal asymmetries. This study investigates the impact of using interactive stratospheric chemistry instead of prescribed ozone on climate change simulations of the Antarctic and Southern Ocean. Two sets of 1960–2010 ensemble transient simulations are conducted with the coupled ocean version of the Goddard Earth Observing System Model, version 5: one with interactive stratospheric chemistry and the other with prescribed ozone derived from the same interactive simulations. The model’s climatology is evaluated using observations and reanalysis. Comparison of the 1979–2010 climate trends between these two simulations reveals that interactive chemistry has important effects on climate change not only in the Antarctic stratosphere, troposphere, and surface, but also in the Southern Ocean and Antarctic sea ice. Interactive chemistry causes stronger Antarctic lower stratosphere cooling and circumpolar westerly acceleration during November–January. It enhances stratosphere–troposphere coupling and leads to significantly larger tropospheric and surface westerly changes. The significantly stronger surface wind stress trends cause larger increases of the Southern Ocean meridional overturning circulation, leading to year-round stronger ocean warming near the surface and enhanced Antarctic sea ice decrease.

scholarly journals Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

2016 ◽  
Vol 16 (4) ◽  
pp. 2185-2206 ◽  
Author(s):  
R. S. Humphries ◽  
A. R. Klekociuk ◽  
R. Schofield ◽  
M. Keywood ◽  
J. Ward ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Southern Ocean ◽  
Sea Ice ◽  
Radiative Forcing ◽  
Free Troposphere ◽  
Radiative Balance ◽  
Air Masses ◽  
Antarctic Sea Ice ◽  
Ocean Region ◽  
The Antarctic

Abstract. Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of cloud and aerosol over the Southern Ocean.

scholarly journals Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea-ice

2015 ◽  
Vol 15 (20) ◽  
pp. 29125-29170 ◽  
Author(s):  
R. S. Humphries ◽  
A. R. Klekociuk ◽  
R. Schofield ◽  
M. Keywood ◽  
J. Ward ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Southern Ocean ◽  
Sea Ice ◽  
Radiative Properties ◽  
Free Troposphere ◽  
Air Masses ◽  
Antarctic Sea Ice ◽  
Ocean Region ◽  
The Antarctic ◽  
Natural Aerosol

Abstract. The effect of aerosols on clouds and their radiative properties is one of the largest uncertainties in our understanding of radiative forcing. A recent study has concluded that better characterisation of pristine, natural aerosol processes leads to the largest reduction in these uncertainties. Antarctica, being far from anthropogenic activities, is an ideal location for the study of natural aerosol processes. Aerosol measurements in Antarctica are often limited to boundary layer air-masses at spatially sparse coastal and continental research stations, with only a handful of studies in the sea ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the ice-breaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the Polar Front, with mean Polar Cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air-masses quickly from the free-troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea ice boundary layer air-masses travelled equator-ward into the low albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei where, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of cloud and aerosol over the Southern Ocean.

Highly branched isoprenoids as proxies for variable sea ice conditions in the Southern Ocean

2011 ◽  
Vol 23 (5) ◽  
pp. 487-498 ◽  
Author(s):  
Guillaume Massé ◽  
Simon T. Belt ◽  
Xavier Crosta ◽  
Sabine Schmidt ◽  
Ian Snape ◽  
...  
Keyword(s):  
Organic Matter ◽  
Southern Ocean ◽  
Sea Ice ◽  
Sediment Sample ◽  
East Antarctica ◽  
The Arctic ◽  
Sediment Samples ◽  
Isotopic Compositions ◽  
Antarctic Sea Ice ◽  
Ice Conditions

AbstractConcentrations of a highly branched isoprenoid (HBI) diene determined in over 200 sediment samples from the Arctic co-vary with those of an HBI monoene (IP25) shown previously to be a sedimentary sea ice proxy for the Arctic. The same diene, but not monoene IP25, occurred in nine sea ice samples collected from various locations around Antarctica. The diene has been reported previously in Antarctic sea ice diatoms and the 13C isotopic compositions of the diene determined in two Antarctic sea ice samples were also consistent with an origin from sea ice diatoms (δ13C -5.7 to -8.5‰). In contrast, HBIs found in two Antarctic phytoplankton samples did not include the diene but comprised a number of tri- to pentaenes. In sediment samples collected near Adélie Land, East Antarctica, both the diene and the tri- to pentaenes often co-occurred. 13C isotopic compositions of the tri- to pentaenes in three sediment samples ranged from -35 to -42‰ whereas that of the diene in a sediment sample was -18‰. We propose the presence of this isotopically 13C enriched HBI diene in Antarctic sediments to be a useful proxy indicator for contributions of organic matter derived from sea ice diatoms. A ratio of the concentrations of diene/trienes might reflect the relative contributions of sea ice to phytoplanktonic inputs of organic matter to Antarctic sediments.

scholarly journals Interannual and regional variability of Southern Ocean snow on sea ice

2006 ◽  
Vol 44 ◽  
pp. 53-57 ◽  
Author(s):  
Thorsten Markus ◽  
Donald J. Cavalieri
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Snow Depth ◽  
Critical Role ◽  
Ice Cover ◽  
Insulation Property ◽  
Regional Variability ◽  
Indirect Measure ◽  
Antarctic Sea Ice ◽  
The Antarctic

AbstractSnow depth on sea ice plays a critical role in the heat exchange between ocean and atmosphere because of its thermal insulation property. Furthermore, a heavy snow load on the relatively thin Southern Ocean sea-ice cover submerges the ice floes below sea level, causing snow-to-ice conversion. Snowfall is also an important freshwater source into the weakly stratified ocean. Snow-depth on sea-ice information can be used as an indirect measure of solid precipitation. Satellite passive microwave data are used to investigate the interannual and regional variability of the snow cover on sea ice. In this study we make use of 12 years (1992–2003) of Special Sensor Microwave/Imager (SSM/I) radiances to calculate average monthly snow depth on the Antarctic sea-ice cover. For the Antarctic sea-ice region as a whole, we find that September snow depth and sea-ice area are negatively correlated, which is not the case for individual regions. An analysis of the snow depth around Antarctica was undertaken. The results show an overall increase in snow depth for each of the five Antarctic sectors and the region as a whole, but only the Indian Ocean sector and the entire Southern Ocean show a statistically significant increase. There is a partial eastward propagation of maximum snow depths, which may be related to the Antarctic Circumpolar Wave. The overall trend and the variability of regional snow-depth distributions are also in agreement with cyclone density.

Life in the Antarctic sea ice zone

Polar Record ◽  
1991 ◽  
Vol 27 (162) ◽  
pp. 249-253 ◽  
Author(s):  
Gotthilf Hempel
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Late Summer ◽  
Euphausia Superba ◽  
Breeding Population ◽  
Climatic Changes ◽  
Weddell Sea ◽  
Antarctic Sea Ice ◽  
Ice Floes ◽  
The Antarctic

AbstractSeasonal ice of the Southern Ocean, occupying some 15 x 106 km2, supports a distinctive biota based on algae that live on, within and immediately beneath the ice floes. How this annually-forming habitat recruits its biota, and the fate of the biota after the ice thaws in late summer, are little-known. Studies in the Weddell Sea in 1984–88 have shown that the seasonal ice is important as the wintering substrate of krill Euphausia superba which, together with other zooplankton and fish, supports a large breeding population of seals and penguins. Clearly a key habitat in the economy of the Southern Ocean, this seasonal ice is likely to be vulnerable to small climatic changes.

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