HR: 0800h
AN: U21C-0631    [Abstracts]
TI: Low-Frequency Ocean Bottom Pressure Signals in the North Pacific
AU: * Chambers, D P
EM: chambers@csr.utexas.edu
AF: Center for Space Research, The University of Texas at Austin 3925 W. Braker Lane, Suite 200, Austin, TX 78759, United States
AU: Willis, J K
EM: joshua.k.willis@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States
AB: Ocean Bottom Pressure (OBP) from two numerical models, the Gravity Recovery and Climate Experiment (GRACE), and from steric-corrected altimetry are examined in the North Pacific. Much previous work has been done on the seasonal cycle of OBP in the North Pacific; we will focus on the low-frequency signal that appears as a trend from January 2004 to December 2006. OBP from the two models increased significantly in only one area: the Northwest Pacific, north of the Kuroshio Extension Current (KEC). The two measurements (GRACE and steric-corrected altimetry) also show an increase in the same area, but with a magnitude roughly 2 to 3 times higher. GRACE and steric-corrected altimetry also show a significant increase in the eastern part of the basin off the coast of North America of nearly the same magnitude: both data show a similar rate of increase. The change in the Northwest Pacific is linked to a slow-down in the KEC over the 3-year period. We demonstrate that the trend observed off the coast of North America is not caused by leakage of hydrology into the GRACE measurements, but may be related to gravitational changes caused by changes in the nearby land water storage. Such dynamics are not included in ocean models. GRACE and steric-corrected altimetry are completely independent observations of OBP. Based on the fact that these two measurements agree so well, we conclude that OBP has significant low-frequency variations in the North Pacific and that these signals are underestimated by numerical models.
DE: 1217 Time variable gravity (7223, 7230)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
SC: Union [U]
MN: 2007 Fall Meeting