On the wet tropospheric correction for altimetry in coastal regions

In order to correct the altimeter range for tropospheric humidity, a microwave radiometer is added to altimetry missions [Envisat/microwave radiometer, Jason/Jason Radiometer, and TOPEX-Poseidon/TOPEX Microwave Radiometer (TMR)]. Over open ocean, the combination is satisfactory. This is not the case in coastal zones, where the signal coming from the surrounding land surzones contaminates the radiometer measurement and makes the method unsuitable. lit this paper, a radiometer is built, using data from a field experiment (in situ measurements and collocated TMR measurements) and analyses from a mesoscale-forecast model. This simulator is used to perform sensitivity tests and to evaluate the current methods to the wet tropospheric correction, in transition areas. The of this paper is to analyze and compare the performances these methods. After examining simple correction methods extension of the open-sea wet tropospheric correction and use of meteorological model value), we evaluated the feasibility and performances of two methods, which propose to take into account the land-surface effect in the brightness-temperature estimation. The latter was found to give significantly better results.