Waveform Retracking of Topex/Poseidon Altimeter in China Seas and Its Vicinity

Abstract

AbstractJust as in the open oceans, the altimeter data in the coastal zone can provide valuable information on wave heights, structure of the geoid and the associated gravity field, and dynamic sea surface topography. Because of this wealth of information, many scientists are seeking to extend the use of altimeter data to the shoreline. There are many different methods described in the literature that are available for re‐tracking altimeter waveform data. All the various re‐tracking algorithms have their own unique advantages and disadvantages, and it is generally accepted that no single algorithm can meet the diverse needs of all altimetry data users. To obtain accurate altimeter data in offshore of China Sea and its vicinity, we have reprocessed the raw Topex/Poseidon altimeter waveform data using more sophisticated algorithms, based on a fit of the waveform to a 5 parameters function. Re‐tracking altimetry data is done by computing the departure of the waveform's leading edge from the tracking gate of altimeter and correcting the satellite range measurement accordingly. On the base of colleagues' experience, reprocessed Topex/Poseidon altimeter waveform data is used to generate a time series of sea surface height. The post‐processed altimeter waveform data is compared with the data from tide gauge station in the China Seas, which close to the ground tracks of satellite. The comparison shows that shallow water areas can be investigated with much more data and closer to the coastal line than the official products.