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/MWR, Jason/JMR, TOPEX-Poseidon/TMR). Over open ocean, the combination altimeter/radiometer is satisfactory. This is not the case in coastal zones, where the signal coming from the surrounding land surfaces contaminates the radiometer measurement and makes the humidity retrieval method unsuitable. In this paper, a radiometer simulator is built. This simulator is used to perform sensitivity tests and to evaluate the current methods to retrieve the wet tropospheric correction in transition areas. After examining simple corrections, we evaluated the feasibility and performances of a method which proposes to take into account the land surface effect in the brightness temperature estimation.