scholarly journals A Complete Picture of Southern Ocean Surface Circulation

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Kate Wheeling
Keyword(s):  
Southern Ocean ◽  
Ocean Surface ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Complete Picture ◽  
Surface Circulation ◽  
Circulation Patterns ◽  
First Time ◽  
Ocean Surface Circulation

For the first time, researchers combine estimates of sea surface height and circulation patterns in both ice-covered and ice-free regions of the Southern Ocean.

Evolution of Arctic Ocean surface circulation from 1958 to 2017

2021 ◽  
Vol 206 ◽  
pp. 103638
Author(s):  
Yilin Yang ◽  
Yuanzhi Zhang ◽  
X. San Liang ◽  
Qiuming Cheng ◽  
Jin Yeu Tsou
Keyword(s):  
Arctic Ocean ◽  
Ocean Surface ◽  
Surface Circulation ◽  
Ocean Surface Circulation

High dependence of Ordovician ocean surface circulation on atmospheric CO2 levels

2016 ◽  
Vol 458 ◽  
pp. 39-51 ◽  
Author(s):  
Alexandre Pohl ◽  
Elise Nardin ◽  
Thijs R.A. Vandenbroucke ◽  
Yannick Donnadieu
Keyword(s):  
Ocean Surface ◽  
Atmospheric Co2 ◽  
Surface Circulation ◽  
Co2 Levels ◽  
Ocean Surface Circulation

Seasonal variations of the ocean surface circulation in the vicinity of Palau

2006 ◽  
Vol 62 (4) ◽  
pp. 413-426 ◽  
Author(s):  
Scott F. Heron ◽  
E. Joseph Metzger ◽  
William J. Skirving
Keyword(s):  
Seasonal Variations ◽  
Ocean Surface ◽  
Surface Circulation ◽  
Ocean Surface Circulation

scholarly journals Defining Southern Ocean fronts using unsupervised classification

Ocean Science ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. 1545-1562
Author(s):  
Simon D. A. Thomas ◽  
Daniel C. Jones ◽  
Anita Faul ◽  
Erik Mackie ◽  
Etienne Pauthenet
Keyword(s):  
Southern Ocean ◽  
Edge Detection ◽  
Detection Method ◽  
Unsupervised Classification ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Near Surface ◽  
Ocean Fronts ◽  
Dynamic Height ◽  
Edge Detection Method

Abstract. Oceanographic fronts are transitions between thermohaline structures with different characteristics. Such transitions are ubiquitous, and their locations and properties affect how the ocean operates as part of the global climate system. In the Southern Ocean, fronts have classically been defined using a small number of continuous, circumpolar features in sea surface height or dynamic height. Modern observational and theoretical developments are challenging and expanding this traditional framework to accommodate a more complex view of fronts. Here, we present a complementary new approach for calculating fronts using an unsupervised classification method called Gaussian mixture modelling (GMM) and a novel inter-class parameter called the I-metric. The I-metric approach produces a probabilistic view of front location, emphasising the fact that the boundaries between water masses are not uniformly sharp across the entire Southern Ocean. The I-metric approach uses thermohaline information from a range of depth levels, making it more general than approaches that only use near-surface properties. We train the GMM using an observationally constrained state estimate in order to have more uniform spatial and temporal data coverage. The probabilistic boundaries defined by the I-metric roughly coincide with several classically defined fronts, offering a novel view of this structure. The I-metric fronts appear to be relatively sharp in the open ocean and somewhat diffuse near large topographic features, possibly highlighting the importance of topographically induced mixing. For comparison with a more localised method, we also use an edge detection approach for identifying fronts. We find a strong correlation between the edge field of the leading principal component and the zonal velocity; the edge detection method highlights the presence of jets, which are supported by thermal wind balance. This more localised method highlights the complex, multiscale structure of Southern Ocean fronts, complementing and contrasting with the more domain-wide view offered by the I-metric. The Sobel edge detection method may be useful for defining and tracking smaller-scale fronts and jets in model or reanalysis data. The I-metric approach may prove to be a useful method for inter-model comparison, as it uses the thermohaline structure of those models instead of tracking somewhat ad hoc values of sea surface height and/or dynamic height, which can vary considerably between models. In addition, the general I-metric approach allows front definitions to shift with changing temperature and salinity structures, which may be useful for characterising fronts in a changing climate.

scholarly journals Sea surface height anomaly and geostrophic velocity from altimetry measurements over the Arctic Ocean (2011–2018)

2021 ◽  
Author(s):  
Francesca Doglioni ◽  
Robert Ricker ◽  
Benjamin Rabe ◽  
Torsten Kanzow
Keyword(s):  
Large Scale ◽  
Sea Surface Height ◽  
Sea Surface ◽  
The Arctic ◽  
Height Anomaly ◽  
Near Surface ◽  
Geostrophic Velocity ◽  
Surface Ocean ◽  
Surface Circulation ◽  
Sea Surface Height Anomaly

Abstract. In recent decades the decline of the Arctic sea ice has modified vertical momentum fluxes from the atmosphere to the ice and the ocean, thereby affecting the surface circulation. In the past ten years satellite altimetry has contributed to understand these changes. However, data from ice-covered regions require dedicated processing, originating inconsistency between ice-covered and open ocean regions in terms of biases, corrections and data coverage. Thus, efforts to generate consistent Arctic-wide datasets are still required to enable the study of the Arctic Ocean surface circulation at basin-wide scales. Here we provide and assess a monthly gridded dataset of sea surface height anomaly and geostrophic velocity. This dataset is based on Cryosat-2 observations over ice-covered and open ocean areas of the Arctic up to 88° N for the period 2011 to 2018, interpolated using the Data-Interpolating Variational Analysis (DIVA) method. Geostrophic velocity was not available north of 82° N before this study. To examine the robustness of our results, we compare the generated fields to one independent altimetry dataset and independent data of ocean bottom pressure, steric height and near-surface ocean velocity from moorings. Results from the comparison to near-surface ocean velocity show that our geostrophic velocity fields can resolve seasonal to interannual variability of boundary currents wider than about 50 km. We further discuss the seasonal cycle of sea surface height and geostrophic velocity in the context of previous literature. Large scale features emerge, i.e. Arctic-wide maximum sea surface height between October and January, with the highest amplitude over the shelves, and basin wide seasonal acceleration of Arctic slope currents in winter. We suggest that this dataset can be used to study not only the large scale sea surface height and circulation but also the regionally confined boundary currents. The dataset is available in netCDF format from PANGAEA at [data currently under review].

scholarly journals Impact of combining GRACE and GOCE gravity data on ocean circulation estimates

Ocean Science ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 65-79 ◽  
Author(s):  
T. Janjić ◽  
J. Schröter ◽  
R. Savcenko ◽  
W. Bosch ◽  
A. Albertella ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Gravity Data ◽  
Sea Surface Height ◽  
Ocean Model ◽  
Weddell Sea ◽  
Sea Surface ◽  
Altimeter Data ◽  
Surface Drifters ◽  
Ocean Topography

Abstract. With the focus on the Southern Ocean circulation, results of assimilation of multi-mission-altimeter data and the GRACE/GOCE gravity data into the finite element ocean model (FEOM) are investigated. We use the geodetic method to obtain the dynamical ocean topography (DOT). This method combines the multi-mission-altimeter sea surface height and the GRACE/GOCE gravity field. Using the profile approach, the spectral consistency of both fields is achieved by filtering the sea surface height and the geoid. By combining the GRACE and GOCE data, a considerably shorter filter length can be used, which results in more DOT details. We show that this increase in resolution of measured DOT carries onto the results of data assimilation for the surface data. By assimilating only absolute dynamical topography data using the ensemble Kalman filter, we were able to improve modeled fields. Results are closer to observations which were not used for assimilation and lie outside the area covered by altimetry in the Southern Ocean (e.g. temperature of surface drifters or deep temperatures in the Weddell Sea area at 800 m depth derived from Argo composite.)

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