Seasonal variation of ocean bottom pressure derived from Gravity Recovery and Climate Experiment (GRACE): local validation and global patterns.

Kanzow, Torsten, Flechtner, F., Chave, A., Schmidt, R., Schwintzer, P. and Send, Uwe (2005) Seasonal variation of ocean bottom pressure derived from Gravity Recovery and Climate Experiment (GRACE): local validation and global patterns. Open Access Journal of Geophysical Research: Oceans, 110 . C09001. DOI 10.1029/2004JC002772.

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Abstract

The Gravity Recovery and Climate Experiment (GRACE) processing centers at the GeoForschungsZentrum Potsdam (GFZ) and the University of Texas Center for Space Research (UTCSR) provide time series of monthly gravity field solutions covering the period since mission launch in March 2002. Although the achieved accuracy still remains an order of magnitude below the mission's baseline goal, these time series have successfully been used to study terrestrial phenomena such as water storage variations. Over the oceans, the monthly gravity field solutions can be converted into estimates of the fluctuating ocean bottom pressure (OBP), which is the sum of atmospheric and oceanic mass variations. The GRACE products may be validated against in situ OBP observations which are available from a ground truth site in the tropical northwest Atlantic Ocean. Large differences are observed between the in situ and GRACE-derived OBP which are investigated by comparing the tidal and nontidal ocean models used at GFZ and UTCSR for dealiasing short-term (<2 months) mass variations from satellite measurements. Results show that the barotropic nontidal and tide models need improvement at periods shorter than 1 day and longer than 2 weeks. On a global scale the monthly OBP fields from GRACE generally overestimate the variability compared to ocean general circulation models, especially in tropical regions. This may be attributed to continuing deficiencies in GRACE data processing. Nevertheless, there is some initial evidence that GRACE possesses the potential to observe large-scale averages of bottom pressure fluctuations.

Document Type: Article
Keywords: Oceanography; Geodesy; gravity, geoid, ocean bottom pressure, deep ocean currents, ocean tides, in situ measurements
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/2004JC002772
ISSN: 2169-9275
Projects: CLIVAR
Date Deposited: 03 Dec 2008 16:51
Last Modified: 19 Apr 2018 09:06
URI: http://oceanrep.geomar.de/id/eprint/3776

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