HR: 08:30h
AN: G31A-03    [Abstracts]
TI: El Niño and La Niña Signals in Sea Level, Hydrological Mass Redistribution, and Degree- Two Geoid Coefficients
AU: * Landerer, F W
EM: felix.landerer@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Jungclaus, J H
EM: johann.jungclaus@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Marotzke, J
EM: jochem.marotzke@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AB: We assess El Niño-Southern Oscillation (ENSO) related variability of steric and eustatic sea level, hydrological mass redistribution in the atmosphere and on the continents, and the corresponding signals in the degree-two geoid coefficients. The analysis utilizes 200 years of simulated monthly data from the ECHAM5/MPI-OM coupled atmosphere-ocean general circulation model, which includes a land-surface and runoff scheme. In the model, eustatic sea level anomalies are mostly balanced by continental water storage. Large eustatic sea level changes (up to 7 mm over 3 years) and continental water storage occur concurrently with some of the simulated ENSO events, but sign and amplitude vary. Therefore, we find no systematic, linear response of eustatic sea level to ENSO events. Steric sea level, on the other hand, varies significantly in phase with ENSO, but there is considerable decadal variability that cannot be linked to ENSO. Atmospheric water vapor content is strongly correlated with ENSO variability, and continental water storage is weakly correlated with ENSO. Based on the geographical pattern of hydrological surface mass load anomalies, we find significant ENSO related variability in the S₂₁ and C₂₀ geoid coefficients, but not in C₂₁. The largest contributions to the S₂₁ component come from mass redistribution within the oceans, and from continental water storage loading anomalies. For the C₂₀ component, the largest ENSO-related contribution comes from continental water storage loading anomalies, whereas the contribution from mass redistribution within the oceans is not significantly correlated with ENSO. Therefore, we suggest that ocean mass redistribution associated with the observed 1997/1998 C₂₀ (or J2) anomaly (Dickey et al., 2002) was most likely not dynamically linked to ENSO.
DE: 1217 Time variable gravity (7223, 7230)
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
SC: Geodesy [G]
MN: 2007 Fall Meeting