Brightness temperature retrieval with scale-model antenna patterns of the aquarius l-band radiometer

The Aquarius is a L-band passive/active instrument onboard a spacecraft due for launch in 2010, targeting sea surface salinity retrieval with an accuracy better than 0.2 psu. Measurement and retrieval of salinity by the Aquarius radiometer are simulated using a radiative transfer model. The cross-polarization coupling in the antenna pattern complicates the correction of the Faraday rotation effect in the ionosphere, causing errors in brightness temperature up to several Kelvin. The second-order correction for the Faraday effect is developed and reduces the retrieval error better than the required accuracy (~less 0.1 K).