Surface pressure and wind stress effects on sea level change estimations from TOPEX/Poseidon satellite altimetry in the Mediterranean Sea

Abstract

Using the classical inverse barometer (IB) correction and the Modèle d'Onde de Gravité à 2 Dimensions (MOG2D) barotropic model in the Mediterranean Sea during the 1993-2002 period, it is shown that surface pressure and wind stress forcing significantly contribute to sea level elevation variations observed with Ocean Topography Experiment (TOPEX)/Poseidon (T/P) satellite altimetry. The barotropic model allows the authors to estimate the high-frequency atmospheric ocean response that is aliased into the altimetric sea level. Applying the model barotropic correction allows them to reduce the T/P standard deviation by a mean of 21% over the whole basin, whereas the classical IB correction reduces the standard deviation by only 16%. The trend in sea level rise is also strongly affected due to the aliasing effect, especially when short periods are considered. On a 3-yr period, the correction associated with either of these two models can reach 10-12 mm yr-1. Applying the barotropic model correction rather than the IB correction can also affect the linear trend estimations by more than 6-7 mm yr-1. For a 9-yr window, the IB/MOG2D correction can contribute 1.8-2 mm yr-1 in magnitude. The local corrected linear trends confirm the previous analysis pattern but on a local scale, with the linear trend magnitudes reaching values between -24 and +29 mm yr-1. © 2008 American Meteorological Society.