Sea Ice on the Southern Ocean
Year-round satellite records of sea ice distribution now extend over more than two decades, providing a valuable tool to investigate related characteristics and circulations in the Southern Ocean. We have studied a variety of features indicative of oceanic and atmospheric interactions with Antarctic...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19980021232 2023-05-15T13:42:49+02:00 Sea Ice on the Southern Ocean Jacobs, Stanley S. Unclassified, Unlimited, Publicly available Mar. 1998 application/pdf http://hdl.handle.net/2060/19980021232 unknown Document ID: 19980021232 http://hdl.handle.net/2060/19980021232 No Copyright CASI Oceanography NASA/CR-1998-207495 NAS 1.26:207495 1998 ftnasantrs 2019-08-31T23:02:17Z Year-round satellite records of sea ice distribution now extend over more than two decades, providing a valuable tool to investigate related characteristics and circulations in the Southern Ocean. We have studied a variety of features indicative of oceanic and atmospheric interactions with Antarctic sea ice. In the Amundsen & Bellingshausen Seas, sea ice extent was found to have decreased by approximately 20% from 1973 through the early 1990's. This change coincided with and probably contributed to recently warmer surface conditions on the west side of the Antarctic Peninsula, where air temperatures have increased by approximately 0.5 C/decade since the mid-1940's. The sea ice decline included multiyear cycles of several years in length superimposed on high interannual variability. The retreat was strongest in summer, and would have lowered the regional mean ice thickness, with attendant impacts upon vertical heat flux and the formation of snow ice and brine. The cause of the regional warming and loss of sea ice is believed to be linked to large-scale circulation changes in the atmosphere and ocean. At the eastern end of the Weddell Gyre, the Cosmonaut Polyna revealed greater activity since 1986, a recurrence pattern during recent winters and two possible modes of formation. Persistence in polynya location was noted off Cape Ann, where the coastal current can interact more strongly with the Antarctic Circumpolar Current. As a result of vorticity conservation, locally enhanced upwelling brings warmer deep water into the mixed layer, causing divergence and melting. In the Ross Sea, ice extent fluctuates over periods of several years, with summer minima and winter maxima roughly in phase. This leads to large interannual cycles of sea ice range, which correlate positively with meridinal winds, regional air temperatures and subsequent shelf water salinities. Deep shelf waters display considerable interannual variability, but have freshened by approximately 0.03/decade since the late 1950's. That could have slowed the thermohaline circulation beneath the Ross Ice Shelf and the properties or volume of local bottom water production. Other/Unknown Material Antarc* Antarctic Antarctic Peninsula Ice Shelf Ross Ice Shelf Ross Sea Sea ice Southern Ocean NASA Technical Reports Server (NTRS) Antarctic Antarctic Peninsula Cape Ann ENVELOPE(51.367,51.367,-66.167,-66.167) Ross Ice Shelf Ross Sea Southern Ocean The Antarctic Weddell |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Oceanography |
spellingShingle |
Oceanography Jacobs, Stanley S. Sea Ice on the Southern Ocean |
topic_facet |
Oceanography |
description |
Year-round satellite records of sea ice distribution now extend over more than two decades, providing a valuable tool to investigate related characteristics and circulations in the Southern Ocean. We have studied a variety of features indicative of oceanic and atmospheric interactions with Antarctic sea ice. In the Amundsen & Bellingshausen Seas, sea ice extent was found to have decreased by approximately 20% from 1973 through the early 1990's. This change coincided with and probably contributed to recently warmer surface conditions on the west side of the Antarctic Peninsula, where air temperatures have increased by approximately 0.5 C/decade since the mid-1940's. The sea ice decline included multiyear cycles of several years in length superimposed on high interannual variability. The retreat was strongest in summer, and would have lowered the regional mean ice thickness, with attendant impacts upon vertical heat flux and the formation of snow ice and brine. The cause of the regional warming and loss of sea ice is believed to be linked to large-scale circulation changes in the atmosphere and ocean. At the eastern end of the Weddell Gyre, the Cosmonaut Polyna revealed greater activity since 1986, a recurrence pattern during recent winters and two possible modes of formation. Persistence in polynya location was noted off Cape Ann, where the coastal current can interact more strongly with the Antarctic Circumpolar Current. As a result of vorticity conservation, locally enhanced upwelling brings warmer deep water into the mixed layer, causing divergence and melting. In the Ross Sea, ice extent fluctuates over periods of several years, with summer minima and winter maxima roughly in phase. This leads to large interannual cycles of sea ice range, which correlate positively with meridinal winds, regional air temperatures and subsequent shelf water salinities. Deep shelf waters display considerable interannual variability, but have freshened by approximately 0.03/decade since the late 1950's. That could have slowed the thermohaline circulation beneath the Ross Ice Shelf and the properties or volume of local bottom water production. |
format |
Other/Unknown Material |
author |
Jacobs, Stanley S. |
author_facet |
Jacobs, Stanley S. |
author_sort |
Jacobs, Stanley S. |
title |
Sea Ice on the Southern Ocean |
title_short |
Sea Ice on the Southern Ocean |
title_full |
Sea Ice on the Southern Ocean |
title_fullStr |
Sea Ice on the Southern Ocean |
title_full_unstemmed |
Sea Ice on the Southern Ocean |
title_sort |
sea ice on the southern ocean |
publishDate |
1998 |
url |
http://hdl.handle.net/2060/19980021232 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(51.367,51.367,-66.167,-66.167) |
geographic |
Antarctic Antarctic Peninsula Cape Ann Ross Ice Shelf Ross Sea Southern Ocean The Antarctic Weddell |
geographic_facet |
Antarctic Antarctic Peninsula Cape Ann Ross Ice Shelf Ross Sea Southern Ocean The Antarctic Weddell |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Shelf Ross Ice Shelf Ross Sea Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Shelf Ross Ice Shelf Ross Sea Sea ice Southern Ocean |
op_source |
CASI |
op_relation |
Document ID: 19980021232 http://hdl.handle.net/2060/19980021232 |
op_rights |
No Copyright |
_version_ |
1766173101334200320 |