scholarly journals Antarctic Circumpolar Wave in a coupled ocean-atmosphere model

1998 ◽  
Vol 27 ◽  
pp. 483-487 ◽  
Author(s):  
T. Moroi ◽  
A. Kitoh ◽  
H. Koide
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
High Density ◽  
Sea Surface ◽  
Ice Formation ◽  
Geostrophic Velocity ◽  
Antarctic Circumpolar Wave ◽  
Ocean Atmosphere ◽  
Velocity Anomalies ◽  
Atmosphere Model

An Antarctic Circumpolar Wave (ACW) is simulated by a global coupled ocean-atmosphere model. Time-longitude diagrams of anomalies in sea-surface temperature (SST) and sea-surface salinity (SSS) show that anomalies propágale eastward, taking 20-30 years to encircle the pole. The time taken is 2-3 times longer than indicated by observations, due to the relatively slow speed of the modelled Antarctic Circumpolar Current (ACC). High-SSS anomalies correspond to high-SST anomalies and high-density anomalies, and thus to low sea-surface height anomalies, indicating that salinity IS a dominant factor for dynamics with in the Southern Ocean and is indispensable for understanding the mechanism of the ACW. Sea-ice formation is suppressed southward of warm, saline surface-water regions. High sea-ice concentration anomalies correspond to thick sea-ice anomalies. Empirical orthogonal function analyses of SSTanomalies for both model and observation show that the dominant mode in the Southern Ocean has a spatial pattern closely related to El Niño activity. Sea-level pressure (SLP) anomalies propagate eastward with the ACW. High SLP anomalies in the atmosphere correspond to low-density anomalies 111 the ocean. The ACC has clockwise geostrophic velocity anomalies over high-density anomaly regions with upwelling. Both heat and salt are transported from the deep layer to the surface layer by upwelling. This could suppress sea-ice formation directly. Anomalous horizontal advection of heat and salt by geostrophic velocity anomalies in the ACC appears to influence the anomalies in SST, SSS and sea ice.

scholarly journals Southern Ocean frontal structure and sea-ice formation rates revealed by elephant seals

2008 ◽  
Vol 105 (33) ◽  
pp. 11634-11639 ◽  
Author(s):  
J.-B. Charrassin ◽  
M. Hindell ◽  
S. R. Rintoul ◽  
F. Roquet ◽  
S. Sokolov ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ice Formation ◽  
Elephant Seals ◽  
Frontal Structure

scholarly journals Interrelationships of Sea Surface Salinity, Chlorophyll-α Concentration, and Sea Surface Temperature Near the Antarctic Ice Edge

2021 ◽  
pp. 1-50
Author(s):  
Cynthia Garcia-Eidell ◽  
Josefino C. Comiso ◽  
Max Berkelhammer ◽  
Larry Stock
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
Ice Melt ◽  
Biogeochemical Models ◽  
Basin Scale

AbstractSatellite data can now provide a coherent picture of sea surface salinity (SSS), chlorophyll-α concentration (Chl?), sea surface temperature (SST), and sea ice cover across the Southern Ocean. The availability of these data at the basin scale enables novel insight into the physical and biological processes in an area that has historically been difficult to gather in situ data from. The analysis shows large regional and interannual variability of these parameters but also strong coherence across the Southern Ocean. The covariability of the parameters near the marginal ice zone shows a generally negative relationship between SSS and Chl??(r = -0.87). This may in part be attributed to the large seasonality of the variables, but analysis of data within the spring period (from November to December) shows similarly high correlation (r =-0.81). This is the first time that a large-scale robust connection between low salinity and high phytoplankton concentration during ice melt period has been quantified. Chlorophyll-α concentration is also well correlated with SST (r = 0.79) providing a potential indicator of the strength of the temperature limitation on primary productivity in the region. The observed correlation also varied regionally due to differences in ice melt patterns during spring and summer. Overall, this study provides new insights into the physical characteristics of the Southern Ocean as observed from space. In a continually warming and freshening Southern Ocean, the relationships observed here provide key data source for testing ocean biogeochemical models and assessing the effect of sea ice-ocean processes on primary production.

scholarly journals A fully coupled Arctic sea ice-ocean-atmosphere model (ArcIOAM v1.0) based on C-Coupler2: model description and preliminary results

2020 ◽  
Author(s):  
Shihe Ren ◽  
Xi Liang ◽  
Qizhen Sun ◽  
Hao Yu ◽  
L. Bruno Tremblay ◽  
...  
Keyword(s):  
Sea Ice ◽  
Coupled Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Model Description ◽  
Preliminary Results ◽  
Comparison Results ◽  
Arctic Sea ◽  
Ocean Atmosphere ◽  
Atmosphere Model

Abstract. The implementation of a new Arctic regional coupled sea ice-ocean-atmosphere model (ArcIOAM) and its preliminary results in the year of 2012 are presented in this paper. A newly developed coupler, C-Coupler2 (the Community Coupler 2), is used to couple the Arctic sea ice-oceanic configuration of the MITgcm (Massachusetts Institute of Technology general circulation model) with the Arctic atmospheric configuration of the Polar WRF (Weather Research and Forecasting) model. ArcIOAM is demonstrated with focus on seasonal simulation of the Arctic sea ice and ocean state in the year of 2012. The results obtained by ArcIOAM, along with the experiment of one-way coupling strategy, are compared with available observational data and reanalysis products. From the comparison, results obtained from two experiments both realistically capture the sea ice and oceanic variables in the Arctic region over a 1-year simulation period. The two-way coupled model has better performance in terms of sea ice extent, concentration, thickness and SST, especially in summer. This indicates that sea ice-ocean-atmosphere interaction takes a crucial role in controlling Arctic summertime sea ice distribution. The coupled model and documentation are available at  https://doi.org/10.5281/zenodo.3742692 (last access: 9 June 2020), and the source code is maintained at  https://github.com/cdmpbp123/Coupled_Atm_Ice_Oce (last access: 7 April 2020).

scholarly journals Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds

2020 ◽  
pp. 1-47
Author(s):  
Edward W. Doddridge ◽  
John Marshall ◽  
Hajoon Song ◽  
Jean-Michel Campin ◽  
Maxwell Kelley
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Mixed Layer ◽  
Vertical Mixing ◽  
Heat Content ◽  
Ice Cover ◽  
Sea Surface ◽  
Surface Mixed Layer ◽  
Surface Cooling ◽  
Westerly Winds

AbstractThe observational record shows a substantial 40-year upward trend in summertime westerly winds over the Southern Ocean, as characterised by the Southern Annular Mode (SAM) index. Enhanced summertime westerly winds have been linked to cold summertime sea surface temperature (SST) anomalies. Previous studies have suggested that Ekman transport or upwelling is responsible for this seasonal cooling. Here, another process is presented in which enhanced vertical mixing, driven by summertime wind anomalies, moves heat downwards, cooling the sea surface and simultaneously warming the subsurface waters. The anomalously cold SSTs draw heat from the atmosphere into the ocean, leading to increased depth-integrated ocean heat content. The subsurface heat is returned to the surface mixed layer during the autumn and winter as the mixed layer deepens, leading to anomalously warm SSTs and potentially reducing sea ice cover. Observational analyses and numerical experiments support our proposed mechanism, showing that enhanced vertical mixing produces subsurface warming and cools the surface mixed layer. Nevertheless, the dominant driver of surface cooling remains uncertain; the relative importance of advective and mixing contributions to the surface cooling is model dependent. Modeling results suggest that sea ice volume is more sensitive to summertime winds than sea ice extent, implying that enhanced summertime westerly winds may lead to thinner sea ice in the following winter, if not lesser ice extent. Thus, strong summertime winds could precondition the sea ice cover for a rapid retreat in the following melt season.

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