The Inverse Barometer (IB) correction accounts for variations in sea surface height due to atmospheric pressure variations (atmospheric loading). It can reach about ±15 cm and it is calculated from meteorological models.

IB_GDR_J1_cy223_l20_sm
fig 1. Amplitude in metres of Inverse Barometer correction computed from ECMWF atmospheric pressures during the Jason-1 cycle 223. This map is drawn using the BRAT from the Jason-1 GDR products. A Loess filter (value of 20) is applied to obtain a fully coloured plot but it makes some artificial data on coastal areas.

 

The response of the sea surface to changes in atmospheric pressure has a large effect on measured sea surface height.

The inverse barometer correction IB can be easily computed from the dry troposphere correction obtained from the sea level pressure Po:

IB (mm) = -9.948 * ( ΔRdry (mbars) – 1013.3 ) [from Aviso and PoDaac User Handbook – IGDR and GDR Jason-1 Product, 2008].
A 1 mbar atmospheric pressure change corresponds to a linear response of the sea level of about 1 cm.

Further information:

    • C. Wunsch and D. Stammer, Atmospheric loading and the oceanic inverted barometer effect, Reviews of Geophys., 35(1), 79-107, 1997.
    • J. Willebrand, S.. Philander, R.. Pacanowski, The oceanic response to large-scale atmospheric disturbances, J. Phys.Oceanography 10, 411-429, 1980
    • R.M. Ponte, P. Gaspar, Regional analysis of the inverted barometer effect over the global ocean using Topex/Poseidon data and model results, J. Geosphys. Res., 104 (C7), 15587-15601, 1999.
    • D. Stammer, C. Wunsch, R.M. Ponte, De-aliasind of global high frequency barotropic motions in altimeter observations, Geosphys.Res.Lett., 27(8), 1175-1178, 2000.
    • L. Carrère, F. Lyard, Modelling the barotropic response of the global ocean to atmospheric wind and pressure forcing – comparisons with observations , Geosphys.Res.Lett., 30(6), pp 1275, 2003.