Tropical Teleconnections to Antarctic Sea Ice During Austral Spring 2016 in Coupled Pacemaker Experiments

2019 ◽  
Vol 46 (12) ◽  
pp. 6848-6858 ◽  
Author(s):  
Ariaan Purich ◽  
Matthew H. England
Keyword(s):  
Sea Ice ◽  
Austral Spring ◽  
Antarctic Sea Ice ◽  
Tropical Teleconnections

Conditions leading to the unprecedented low Antarctic sea ice extent during the 2016 austral spring season

2017 ◽  
Vol 44 (17) ◽  
pp. 9008-9019 ◽  
Author(s):  
Malte F. Stuecker ◽  
Cecilia M. Bitz ◽  
Kyle C. Armour
Keyword(s):  
Sea Ice ◽  
Spring Season ◽  
Austral Spring ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice

Changes in the lipid composition of Antarctic sea-ice diatom communities during a spring bloom: an indication of community physiological status

1989 ◽  
Vol 1 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Peter D. Nichols ◽  
Anna C. Palmisano ◽  
Mark S. Rayner ◽  
Glen A. Smith ◽  
David C. White
Keyword(s):  
Sea Ice ◽  
Lipid Composition ◽  
Spring Bloom ◽  
Natural Populations ◽  
Coastal Sediments ◽  
Physiological Status ◽  
Austral Spring ◽  
Biological Source ◽  
Antarctic Sea Ice ◽  
Algal Groups

The lipid composition of natural populations of diatoms in the sea ice at McMurdo Sound was determined during the austral spring bloom of 1985, using and Iatroscan TLC–FID system. The major lipid classes in all samples were polar lipids (including phospholipid, glycolipid and chlorophyll) and triacylglycerol, with lesser proportions of free fatty acids. Total lipid increased through November and early December, reaching a maximum (3300 mg m−2 at Cape Armitage and 1800 mg m−2 at Erebus Ice Tongue) c. one week after the chlorophyll a maxima. This increase was largely attributable to a corresponding increase in triacylglycerol. At the lipid maxima, triacylglycerol/polar lipid ratios in the range 1.0 to 2.5 were observed. The dynamic variations in lipid class abundances indicate that profound changes in the physiology of sea-ice diatoms are occurring throughout the spring bloom. A range of sterols (C26–C30) were detected; 24-methylenecholesterol, brassicasterol and 24-ethylcholesterol were the major sterols at the Cape Armitage and Erebus sites. The similarity of the sterol profiles to those of Antarctic freshwater algal communities strongly indicates diatoms as a more probable source of C29 sterols in the freshwater lakes than cyanobacteria or other algal groups. The hydrocarbons isolated from sea-ice diatoms at all sites were dominated by two unsaturated components, n−C21:6 and a diunsaturated isoprenoid C25 alkene. Until this study, no biological source had been validated for the isoprenoid C25:2 diene, even though it has been detected in many estuarine and coastal sediments.

scholarly journals The Early 1990s Change in ENSO–PSA–SAM Relationships and Its Impact on Southern Hemisphere Climate

2015 ◽  
Vol 28 (23) ◽  
pp. 9393-9408 ◽  
Author(s):  
Jin-Yi Yu ◽  
Houk Paek ◽  
Eric S. Saltzman ◽  
Tong Lee
Keyword(s):  
Sea Ice ◽  
Southern Hemisphere ◽  
Air Temperature ◽  
Southern Oscillation ◽  
Phase Relationship ◽  
Surface Air Temperature ◽  
Central Pacific ◽  
Austral Spring ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract This study uncovers an early 1990s change in the relationships between El Niño–Southern Oscillation (ENSO) and two leading modes of the Southern Hemisphere (SH) atmospheric variability: the southern annular mode (SAM) and the Pacific–South American (PSA) pattern. During austral spring, while the PSA maintained a strong correlation with ENSO throughout the period 1948–2014, the SAM–ENSO correlation changed from being weak before the early 1990s to being strong afterward. Through the ENSO connection, PSA and SAM became more in-phase correlated after the early 1990s. The early 1990s is also the time when ENSO changed from being dominated by the eastern Pacific (EP) type to being dominated by the central Pacific (CP) type. Analyses show that, while the EP ENSO can excite only the PSA, the CP ENSO can excite both the SAM and PSA through tropospheric and stratospheric pathway mechanisms. The more in-phase relationship between SAM and PSA impacted the post-1990s Antarctic climate in at least two aspects: 1) a stronger Antarctic sea ice dipole structure around the Amundsen–Bellingshausen Seas due to intensified geopotential height anomalies over the region and 2) a shift in the phase relationships of surface air temperature anomalies among East Antarctica, West Antarctica, and the Antarctic Peninsula. These findings imply that ENSO–Antarctic climate relations depend on the dominant ENSO type and that ENSO forcing has become more important to the Antarctic sea ice and surface air temperature variability in the past two decades and will in the coming decades if the dominance of CP ENSO persists.

scholarly journals Impacts of CP- and EP-El Niño events on the Antarctic sea ice in austral spring

2021 ◽  
pp. 1-76
Author(s):  
Chao Zhang ◽  
Tim Li ◽  
Shuanglin Li
Keyword(s):  
Sea Ice ◽  
El Niño ◽  
El Nino ◽  
Austral Spring ◽  
Southerly Wind ◽  
Cp El Niño ◽  
Antarctic Sea Ice ◽  
Anomalous Anticyclone ◽  
Ep El Niño ◽  
The Antarctic

AbstractBased on observational data analyses and idealized modeling experiments, we investigated the distinctive impacts of central Pacific (CP-) El Niño and eastern Pacific (EP-) El Niño on the Antarctic sea ice concentration (SIC) in austral spring (September to November). The tropical heat sources associated with EP-El Niño and the co-occurred positive phase of Indian Ocean Dipole (IOD) excite two branches of Rossby wave trains that propagate southeastward, causing an anomalous anticyclone over the eastern Ross-Amundsen-Bellingshausen Seas. Anomalous northerly (southerly) wind west (east) of the anomalous anticyclone favor poleward (offshore) movements of sea ice, resulting in a sea ice loss (growth) in the eastern Ross-Amundsen Seas (the Bellingshausen-Weddell Seas). Meanwhile, the anomalous northerly (southerly) wind also advected warmer and wetter (colder and drier) air into the eastern Ross-Amundsen Seas (the Bellingshausen-Weddell Seas), causing surface warming (cooling) through the enhanced (reduced) surface heat fluxes and thus contributing to the sea ice melting (growth). CP-El Niño, however, forces a Rossby wave train that generates an anomalous anticyclone in the eastern Ross-Amundsen Seas, 20° west of that caused by EP-El Niño. Consequently, a positive SIC anomaly occurs in the Bellingshausen Sea. A dry version of the Princeton atmospheric general circulation model was applied to verify the roles of anomalous heating in the tropics. The result showed that EP-El Niño can remotely induce an anomalous anticyclone and associated dipole temperature pattern in the Antarctic region, whereas CP-El Niño generates a similar anticyclone pattern with its location shift westward by 20° in longitudes.

scholarly journals Brief communication: Changing mid-twentieth century Antarctic sea ice variability linked to tropical forcing

2017 ◽  
Author(s):  
Chris S.~M. Turney ◽  
Andrew Klekociuk ◽  
Christopher J. Fogwill ◽  
Violette Zunz ◽  
Hugues Goosse ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
System Modelling ◽  
Austral Spring ◽  
Sea Ice Extent ◽  
Tropical Forcing ◽  
Proxy Records ◽  
Antarctic Sea Ice ◽  
Ice Retreat ◽  
Ice Production

Abstract. Satellite observations demonstrate Antarctic sea ice extent increased between late-1978 and 2015, with significant spatial and seasonal variability. Late spring retreat off George V Land is a major component of the observed increase, but the paucity of proxy records makes interpretation of trends (and impacts) challenging. Here Earth-system modelling and reanalysis demonstrate tropical Pacific warming can trigger an atmospheric Rossby wave response during the austral spring, delaying sea-ice retreat off George V Land. Our results provide new insights into the spatial and temporal role low latitudes play in Antarctic sea-ice production, drift and ocean circulation on decadal to centennial timescales.

High single-cell metabolic activity in Antarctic sea ice bacteria

2008 ◽  
Author(s):  
A Martin ◽  
JA Hall ◽  
R O’Toole ◽  
SK Davy ◽  
KG Ryan
Keyword(s):  
Sea Ice ◽  
Single Cell ◽  
Metabolic Activity ◽  
Cell Metabolic Activity ◽  
Antarctic Sea Ice
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