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Effects of self-attraction and loading on annual variations of ocean bottom pressure

Vinogradova, Nadya T.; Ponte, Rui M.; Tamisiea, Mark E.; Davis, James L.; Hill, Emma M.. 2010 Effects of self-attraction and loading on annual variations of ocean bottom pressure. Journal of Geophysical Research, 115, C06025. 10, pp. 10.1029/2009jc005783

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Abstract/Summary

The impact of self-attraction and loading (SAL) on ocean bottom pressure xi, an effect not previously considered, is analyzed in terms of the mean annual cycle based on decade long estimates of changes in land hydrology, atmospheric pressure, and oceanic circulation. The SAL-related changes in xi occur as a result of deformation of the crust due to loading and self-gravitation of the variable fluid loads. In the absence of SAL, net freshwater input and changes in mean atmospheric pressure over the ocean give rise to a spatially constant xi annual cycle with an amplitude similar to 1-2 cm in equivalent water thickness. Consideration of SAL physics introduces spatial variations that can be significant, particularly around continental boundaries, where the amplitude of deviations can exceed 1 cm. For the spatial variability induced by SAL effects, changes in both land hydrology and atmospheric pressure are important. Effects related to the changing ocean circulation are relatively weaker, apart from a few shallow coastal regions. Comparisons with a few in situ, deep ocean observations indicate that for the most accurate xi estimates, one needs to consider spatially varying SAL-related signals, along with the effects of mean atmospheric pressure and net freshwater input into the oceans. Nevertheless, the most complete estimates, including also effects of ocean circulation, are able to account for only similar to 1/3 of the observed annual variances. Sources of the remaining contribution remain unclear

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2009jc005783
Programmes: Oceans 2025 > Climate, ocean circulation and sea level
ISSN: 0148-0227
Additional Information. Not used in RCUK Gateway to Research.: Vinogradova, Nadya T. Ponte, Rui M. Tamisiea, Mark E. Davis, James L. Hill, Emma M. NASA [NNX07AM77G, NNX08AJ79G]; National Oceanographic Partnership Program ; Natural Environment Research Council The authors are grateful to Patrick Heimbach for making ECCO model output available. The work was supported in part by NASA grants NNX07AM77G and NNX08AJ79G. Additional support was provided by the National Oceanographic Partnership Program through its sponsorship of the ECCO project and by the Natural Environment Research Council's Oceans 2025 Program. Useful interactions in the course of this work with many ECCO colleagues are gratefully acknowledged. The authors also thank two anonymous reviewers for commenting on the manuscript. Amer geophysical union Washington
Additional Keywords: SEA LEVE; GLOBAL OCEAN MODEL; VARIABLITY; OCEAN BOTTOM PRESSURE
NORA Subject Terms: Marine Sciences
Date made live: 20 Apr 2011 14:46
URI: http://nora.nerc.ac.uk/id/eprint/13959

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