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.
|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.
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