Radiometric path delay calibration of ERS-2 with application to altimetric range

The accuracy and stability of the atmospheric wet path delay as measured by the microwave radiometer on-board ERS-2 is crucial to altimetric measures of sea-level change. In this study a GPS receiver on an oil platform in the North Sea is first used to quantify the ERS-2 radiometic wet path delay for the period 1999-2003. The observed discrepancies between the GPS results and the radiometer motivate an extended study utilising a network of 13 IGS stations operational for 1995 through to the present day. The GPS wet path delays are converted to an equivalent brightness temperature on the 23.8GHz channel and used in a subsequent analysis to determine a correction formula. The new formulism is validated by utilising coldest and mean tempertures for each ERS-2 cycle 1-85.