Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model
Water mass transformation in the North Atlantic is examined in an eddy-permitting simulation with the OCCAM ocean general circulation model, forced by realistic surface fluxes over the period 1985-2002. Three Atlantic regions are considered - the subtropics, mid-latitudes, the northeast Atlantic - a...
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ftdoajarticles:oai:doaj.org/article:ddf09e3ad4d94d30ba4882ef43bc9877 2023-05-15T17:06:07+02:00 Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model R. Marsh S. A. Josey A. J. G. de Nurser B. A. Cuevas A. C. Coward 2005-01-01T00:00:00Z https://doaj.org/article/ddf09e3ad4d94d30ba4882ef43bc9877 EN eng Copernicus Publications http://www.ocean-sci.net/1/127/2005/os-1-127-2005.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 1812-0784 1812-0792 https://doaj.org/article/ddf09e3ad4d94d30ba4882ef43bc9877 Ocean Science, Vol 1, Iss 2, Pp 127-144 (2005) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2005 ftdoajarticles 2022-12-31T16:03:42Z Water mass transformation in the North Atlantic is examined in an eddy-permitting simulation with the OCCAM ocean general circulation model, forced by realistic surface fluxes over the period 1985-2002. Three Atlantic regions are considered - the subtropics, mid-latitudes, the northeast Atlantic - along with the Labrador Sea. The oceanic boundaries of each region coincide with hydrographic sections occupied in recent years. These regions broadly represent the formation sites of Eighteen Degree Water (EDW), Subtropical Mode Water (STMW), Subpolar Mode Water (SPMW) and Labrador Sea Water (LSW). Water mass budgets are obtained for each region and year. Terms in the budget comprise surface-forced transformation rates, boundary exchanges and unsteadiness. Transformation rates due to 'total mixing' are obtained as the difference between net and surface transformation rates. Transports at the boundaries are evaluated alongside recent hydrographic section datasets, while surface-driven and mixing-driven transformation rates are compared with estimates based on air-sea flux datasets and inverse analysis of hydrographic data. In general OCCAM compares well with the observations, although two particular discrepancies are identified: deep overflows at high latitudes too light by around 0.2 kg m -3 and spurious heat gain of up to 100 Wm -2 east of the Grand Banks. Over 1985-2002, there is considerable variability on a range of timescales, in the annual surface-driven and mixing-driven formation rates of all four water masses. In the case of EDW and STMW, surface-driven and mixing-driven formation rates largely cancel. This is not so for SPMW and LSW, leading to regional net formation rates of up to 17 Sv and 15 Sv, respectively. In particular, OCCAM successfully simulates the strong LSW formation event of 1989-1994. Article in Journal/Newspaper Labrador Sea North Atlantic Northeast Atlantic Directory of Open Access Journals: DOAJ Articles |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
spellingShingle |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 R. Marsh S. A. Josey A. J. G. de Nurser B. A. Cuevas A. C. Coward Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
Water mass transformation in the North Atlantic is examined in an eddy-permitting simulation with the OCCAM ocean general circulation model, forced by realistic surface fluxes over the period 1985-2002. Three Atlantic regions are considered - the subtropics, mid-latitudes, the northeast Atlantic - along with the Labrador Sea. The oceanic boundaries of each region coincide with hydrographic sections occupied in recent years. These regions broadly represent the formation sites of Eighteen Degree Water (EDW), Subtropical Mode Water (STMW), Subpolar Mode Water (SPMW) and Labrador Sea Water (LSW). Water mass budgets are obtained for each region and year. Terms in the budget comprise surface-forced transformation rates, boundary exchanges and unsteadiness. Transformation rates due to 'total mixing' are obtained as the difference between net and surface transformation rates. Transports at the boundaries are evaluated alongside recent hydrographic section datasets, while surface-driven and mixing-driven transformation rates are compared with estimates based on air-sea flux datasets and inverse analysis of hydrographic data. In general OCCAM compares well with the observations, although two particular discrepancies are identified: deep overflows at high latitudes too light by around 0.2 kg m -3 and spurious heat gain of up to 100 Wm -2 east of the Grand Banks. Over 1985-2002, there is considerable variability on a range of timescales, in the annual surface-driven and mixing-driven formation rates of all four water masses. In the case of EDW and STMW, surface-driven and mixing-driven formation rates largely cancel. This is not so for SPMW and LSW, leading to regional net formation rates of up to 17 Sv and 15 Sv, respectively. In particular, OCCAM successfully simulates the strong LSW formation event of 1989-1994. |
format |
Article in Journal/Newspaper |
author |
R. Marsh S. A. Josey A. J. G. de Nurser B. A. Cuevas A. C. Coward |
author_facet |
R. Marsh S. A. Josey A. J. G. de Nurser B. A. Cuevas A. C. Coward |
author_sort |
R. Marsh |
title |
Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model |
title_short |
Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model |
title_full |
Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model |
title_fullStr |
Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model |
title_full_unstemmed |
Water mass transformation in the North Atlantic over 1985-2002 simulated in an eddy-permitting model |
title_sort |
water mass transformation in the north atlantic over 1985-2002 simulated in an eddy-permitting model |
publisher |
Copernicus Publications |
publishDate |
2005 |
url |
https://doaj.org/article/ddf09e3ad4d94d30ba4882ef43bc9877 |
genre |
Labrador Sea North Atlantic Northeast Atlantic |
genre_facet |
Labrador Sea North Atlantic Northeast Atlantic |
op_source |
Ocean Science, Vol 1, Iss 2, Pp 127-144 (2005) |
op_relation |
http://www.ocean-sci.net/1/127/2005/os-1-127-2005.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 1812-0784 1812-0792 https://doaj.org/article/ddf09e3ad4d94d30ba4882ef43bc9877 |
_version_ |
1766061111381065728 |