DECADAL SEA LEVEL TREND AND VARIABILITY FROM SATELLITE ALTIMETER DATA

Abstract

Global mean sea level trends are routinely computed using satellite altimetry data. These trends remainrelatively stable with time, with the latest value near 3.3 mm yr-1 (e.g., http://sealevel.colorado.edu/).However, regional maps of sea level trends appear less stable and it has been recognized that decadal andinterdecadal variability of the oceans are the likely reasons behind the regional changes in trend values. Weuse Versatile Analysis of ~23-year long time series of sea level from collocated TOPEX, Poseidon, Jason-1and Jason-2 (TPJ) altimeters to infer decadal trends and their uncertainties due to the aliasing (covariances)from interannual and longer-term global and regional atmosphere-ocean variability, such as the PacificDecadal Oscillation, the 18.6-year nodal modulation, the El Ni&ntilde o/Southern Oscillation, the Indian OceanDipole, or the Southern Annual Mode. Examples of these analyses are presented for several regions in thePacific and Indian Oceans and the effects of the length of the TPJ time series on the computed covariancesare discussed.ea level trends appear less stable and it has been recognized that decadal andinterdecadal variability of the oceans are the likely reasons behind the regional changes in trend values. Weuse Versatile Analysis of ~23-year long time series of sea level from collocated TOPEX, Poseidon, Jason-1and Jason-2 (TPJ) altimeters to infer decadal trends and their uncertainties due to the aliasing (covariances)from interannual and longer-term global and regional atmosphere-ocean variability, such as the PacificDecadal Oscillation, the 18.6-year nodal modulation, the El Ni&ntilde o/Southern Oscillation, the Indian OceanDipole, or the Southern Annual Mode. Examples of these analyses are presented for several regions in thePacific and Indian Oceans and the effects of the length of the TPJ time series on the computed covariancesare discussed.