Determining North Atlantic meridional transport variability from pressure on the western boundary: a model investigation.

Bingham, R. J.; Hughes, C. W. ORCID: https://orcid.org/0000-0002-9355-0233. 2008 Determining North Atlantic meridional transport variability from pressure on the western boundary: a model investigation. Journal of Geophysical Research, 113 (C9), C09008. 16, pp. 10.1029/2007JC004679

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Abstract/Summary

In this paper we investigate the possibility of determining North Atlantic meridional transport variability using pressure on the western boundary, focusing on the 42degN latitude of the Halifax WAVE array. We start by reviewing the theoretical foundations of this approach. Next we present results from a model analysis, both statistical and dynamic, that demonstrate the feasibility of the approach. We consider how well we can quantify the meridional transport variability at 42degN given complete knowledge of bottom pressure across the basin, and to what degree this quantification is degraded by first ignoring the effect of intervening topography, and then by using only bottom pressure on the western boundary. We find that for periods of greater than one year we can recover more than 90% of the variability of the main overturning cell at 42degN using only the western boundary pressure, provided we remove the depth-average boundary pressure signal. This signal arises from a basin mode of bottom pressure variability, which has power at all timescales, but that does not in truth have a meridional transport signal associated with it, and from the geostrophic depth-independent compensation of the Ekman transport. An additional benefit of the removal of the depth-average pressure is that this high-frequency Ekman signal, which is essentially noise as far as monitoring the MOC for climatically important changes is concerned, is clearly separated from other modes.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2007JC004679
Programmes:	Oceans 2025 > Climate, ocean circulation and sea level POL Programmes > Sea-level, bottom pressure and space geodesy > Continuous ocean monitoring methods
ISSN:	0148-0227
Additional Keywords:	ATMOSPHERIC SURFACE PRESSURE GENERAL CIRCULATION MODEL SEA LEVEL OVERTURNING CIRCULATION THERMOHALINE CIRCULATION MOMENTUM BALANCE SOUTHERN OCEAN 26.5 DEGREES NORTH ATMOSPHERIC SURFACE PRESSURE GENERAL CIRCULATION MODEL SEA LEVEL OVERTURNING CIRCULATION THERMOHALINE CIRCULATION MOMENTUM BALANCE SOUTHERN OCEAN 26.5 DEGREES NORTH
NORA Subject Terms:	Marine Sciences
Date made live:	17 Dec 2008 14:52 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/5016

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