An Increase of the Indonesian Throughflow by Internal Tidal Mixing in a High‐Resolution Quasi‐Global Ocean Simulation

Abstract. A consistently calibrated 40-year length dataset of visible channel remote sensing reflectance has been derived from the Advanced Very High Resolution Radiometer (AVHRR) sensor global time-series. The dataset uses as its source the Pathfinder Atmospheres – Extended (PATMOS-x) v5.3 Climate Data Record (CDR) for top-of-atmosphere (TOA) visible channel reflectances. This paper describes the theoretical basis for the atmospheric correction procedure and its subsequent implementation, including the necessary ancillary data files used and quality flags applied, in order to determine remote sensing reflectance. The resulting dataset is produced at daily, and archived at monthly, resolution, on a 0.1° × 0.1° grid at https://doi.pangaea.de/10.1594/PANGAEA.892175. The primary aim of deriving this dataset is to highlight regions of the global ocean affected by highly reflective blooms of the coccolithophorid Emiliania Huxleyi over the past 40 years.

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A parameterization of local and remote tidal mixing

10.5194/egusphere-egu2020-3390 ◽

2020 ◽

Author(s):

Casimir de Lavergne ◽

Clément Vic ◽

Gurvan Madec ◽

Fabien Roquet ◽

Amy Waterhouse ◽

...

Keyword(s):

Vertical Mixing ◽

Three Dimensional ◽

Internal Tide ◽

Ocean Model ◽

Internal Tides ◽

Tidal Mixing ◽

Global Ocean ◽

Energy Conserving ◽

Energy Constrained ◽

Lagrangian Tracking

<p>Vertical mixing is often regarded as the Achilles&#8217; heel of ocean models. In particular, few models include a comprehensive and energy-constrained parameterization of mixing by internal ocean tides. Here, we present an energy-conserving mixing scheme which accounts for the local breaking of high-mode internal tides and the distant dissipation of low-mode internal tides. The scheme relies on four static two-dimensional maps of internal tide dissipation, constructed using mode-by-mode Lagrangian tracking of energy beams from sources to sinks. Each map is associated with a distinct dissipative process and a corresponding vertical structure. Applied to an observational climatology of stratification, the scheme produces a global three-dimensional map of dissipation which compares well with available microstructure observations and with upper-ocean finestructure mixing estimates. Implemented in the NEMO global ocean model, the scheme improves the representation of deep water-mass transformation and obviates the need for a constant background diffusivity.</p>

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A global high-resolution data set of ice sheet topography, cavity geometry and ocean bathymetry

10.5194/essd-2016-3 ◽

2016 ◽

Cited By ~ 4

Author(s):

Janin Schaffer ◽

Ralph Timmermann ◽

Jan Erik Arndt ◽

Steen Savstrup Kristensen ◽

Christoph Mayer ◽

...

Keyword(s):

High Resolution ◽

Continental Shelf ◽

Ice Sheet ◽

The Arctic ◽

Global Ocean ◽

Data Set ◽

Antarctic Ice Sheet ◽

Ice Shelves ◽

Surface Topographies ◽

The Antarctic

Abstract. The ocean plays an important role in modulating the mass balance of the polar ice sheets by interacting with the ice shelves in Antarctica and with the marine-terminating outlet glaciers in Greenland. Given that the flux of warm water onto the continental shelf and into the sub-ice cavities is steered by complex bathymetry, a detailed topography data set is an essential ingredient for models that address ice-ocean interaction. We followed the spirit of the global RTopo-1 data set and compiled consistent maps of global ocean bathymetry, upper and lower ice surface topographies and global surface height on a spherical grid with now 30-arc seconds resolution. We used the General Bathymetric Chart of the Oceans (GEBCO_2014) as the backbone and added the International Bathymetric Chart of the Arctic Ocean version 3 (IBCAOv3) and the International Bathymetric Chart of the Southern Ocean (IBCSO) version 1. While RTopo-1 primarily aimed at a good and consistent representation of the Antarctic ice sheet, ice shelves and sub-ice cavities, RTopo-2 now also contains ice topographies of the Greenland ice sheet and outlet glaciers. In particular, we aimed at a good representation of the fjord and shelf bathymetry surrounding the Greenland continent. We corrected data from earlier gridded products in the areas of Petermann Glacier, Hagen Bræ and Sermilik Fjord assuming that sub-ice and fjord bathymetries roughly follow plausible Last Glacial Maximum ice flow patterns. For the continental shelf off northeast Greenland and the floating ice tongue of Nioghalvfjerdsfjorden Glacier at about 79° N, we incorporated a high-resolution digital bathymetry model considering original multibeam survey data for the region. Radar data for surface topographies of the floating ice tongues of Nioghalvfjerdsfjorden Glacier and Zachariæ Isstrøm have been obtained from the data centers of Technical University of Denmark (DTU), Operation Icebridge (NASA/NSF) and Alfred Wegener Institute (AWI). For the Antarctic ice sheet/ice shelves, RTopo-2 largely relies on the Bedmap-2 product but applies corrections for the geometry of Getz, Abbot and Fimbul ice shelf cavities. The data set is available in full and in regional subsets in NetCDF format from the PANGAEA database at https://doi.pangaea.de/10.1594/PANGAEA.856844.

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The Response to a Sudden Change in Indonesian Throughflow in a Global Ocean GCM

Journal of Physical Oceanography ◽

10.1175/1520-0485(1994)024<1895:trtasc>2.0.co;2 ◽

1994 ◽

Vol 24 (9) ◽

pp. 1895-1910 ◽

Cited By ~ 27

Author(s):

Anthony C. Hirst ◽

J. S. Godfrey

Keyword(s):

Sudden Change ◽

Global Ocean ◽

Indonesian Throughflow

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EnOI-Based Data Assimilation Technology for Satellite Observations and ARGO Float Measurements in a High Resolution Global Ocean Model Using the CMF Platform

Communications in Computer and Information Science - Supercomputing ◽

10.1007/978-3-319-55669-7_5 ◽

2016 ◽

pp. 57-66 ◽

Cited By ~ 4

Author(s):

Maxim Kaurkin ◽

Rashit Ibrayev ◽

Alexandr Koromyslov

Keyword(s):

High Resolution ◽

Data Assimilation ◽

Ocean Model ◽

Satellite Observations ◽

Global Ocean ◽

Argo Float

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Decadal changes in the Atlantic Meridional Overturning Circulation in high-resolution simulations of the subpolar North Atlantic

10.5194/egusphere-egu21-7789 ◽

2021 ◽

Author(s):

Claus W. Böning ◽

Arne Biastoch ◽

Klaus Getzlaff ◽

Patrick Wagner ◽

Siren Rühs ◽

...

Keyword(s):

High Resolution ◽

North Atlantic ◽

Deep Convection ◽

Alternative Interpretation ◽

Meridional Overturning Circulation ◽

Global Ocean ◽

Labrador Sea ◽

Overturning Circulation ◽

First Results ◽

Meridional Overturning

<p>A series of global ocean - sea ice model simulations is used to investigate the spatial structure and temporal variability of the sinking branch of the meridional overturning circulation (AMOC) in the subpolar North Atlantic. The experiments include hindcast simulations of the last six decades based on the high-resolution (1/20&#176;) VIKING20X-model forced by the CORE and JRA55-do reanalysis products, supplemented by sensitivity studies with a 1/4&#176;-configuration (ORCA025) aimed at elucidating the roles of variations in the wind stress and buoyancy fluxes. The experiments exhibit different multi-decadal trends in the AMOC, reflecting the well-known sensitivity of ocean-only models to subtle details in the configuration of the subarctic freshwater forcing. All experiments, however, concur in that the dense, southward branch of the overturning is mainly fed by &#8220;sinking&#8221; (in density space) in the Irminger and Iceland Basins, in accordance with the first results of the OSNAP observational program. Remarkably, the contribution of the Labrador Sea has remained small throughout the whole simulation period, even during the phase of extremely strong convection in the early 1990s: i.e., the rate of deep water exported from the subpolar North Atlantic by the DWBC off Newfoundland never differed by more than O(1 Sv) from the DWBC entering the Labrador Sea at Cape Farewell. The model solutions indicate a particular concentration of the sinking along the deep boundary currents south of the Denmark Straits and south of Iceland, pointing to a prime importance for the AMOC of the outflows from the Nordic Seas and their subsequent enhancement by the entrainment of intermediate waters. Since these include the water masses formed by deep convection in the Labrador and southern Irminger Seas, our study offers an alternative interpretation of the dynamical role of decadal changes in Labrador Sea convection intensity in terms of a remote effect on the deep transports established in the outflow regimes.</p>

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Tidal Mixing Signatures in the Hong Kong Coastal Waters from Satellite-Derived Sea Surface Temperature

Remote Sensing ◽

10.3390/rs11010005 ◽

2018 ◽

Vol 11 (1) ◽

pp. 5 ◽

Cited By ~ 2

Author(s):

R. Susanto ◽

Jiayi Pan ◽

Adam Devlin

Keyword(s):

Hong Kong ◽

High Resolution ◽

Surface Temperature ◽

Sea Surface Temperature ◽

Coastal Waters ◽

River Estuary ◽

Pearl River Estuary ◽

Sea Surface ◽

Tidal Mixing ◽

Diurnal Tides

Tidal mixing in the coastal waters of Hong Kong was investigated using a combination of in situ observations and high-resolution satellite-derived sea surface temperature (SST) data. An indicator of tide-induced mixing is a fortnightly (spring-neap cycle) signature in SST due to nonlinear interactions between the two principal diurnal and the two principal semi-diurnal tides. Both semi-diurnal and diurnal tides have strong tidal amplitudes and currents near Hong Kong. As a result, both the near-fortnightly (Mf) and fortnightly (MSf) tides are enhanced due to nonlinear tidal signal interactions. In addition, these fortnightly tidal signals are modulated by seasonal variability, with the maximum seasonal modulation of fortnightly tides occurring during the monsoon transition periods in May and October. The largest fortnightly signals are found in the southwestern part of the Pearl River estuary. Tidal constituent properties vary by space and depth, and high-resolution SST plays a pivotal role in resolving the spatial characteristics of tidal mixing.

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