☆ 4.3 Article

Retracking of SARAL/AltiKa Radar Altimetry Waveforms for Optimal Gravity Field Recovery

MARINE GEODESY (2017)

Journal

MARINE GEODESY

Volume 40, Issue 1, Pages 40-56

Publisher

TAYLOR & FRANCIS INC

DOI: 10.1080/01490419.2016.1265032

Keywords

Gravity field; noise level; SARAL/AltiKa; waveform retracking

Categories

Geochemistry & Geophysics Oceanography Remote Sensing

Funding

973 Project of China [2013CB73301, 2013CB73302]
National Natural Science Foundation of China [41210006, 41304003]
project of Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, China [20150209]
National Geospatial-Intelligence Agency [HM0177-13-1-0008]
NASA SWOT program [NNX16AH64G]

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Abstract

The accuracy of the marine gravity field derived from satellite altimetry depends on dense track spacing as well as high range precision. Here, we investigate the range precision that can be achieved using a new shorter wavelength Ka-band altimeter AltiKa aboard the SARAL spacecraft. We agree with a previous study that found that the range precision given in the SARAL/AltiKa Geophysical Data Records is more precise than that of Ku-band altimeter by a factor of two. Moreover, we show that two-pass retracking can further improve the range precision by a factor of 1.7 with respect to the 40 Hz-retracked data (item of range_40 hz) provided in the Geophysical Data Records. The important conclusion is that a dedicated Ka-band altimeter-mapping mission could substantially improve the global accuracy of the marine gravity field with complete coverage and a track spacing of <6 km achievable in similar to 1.3 years. This would reveal thousands of uncharted seamounts on the ocean floor as well as important tectonic features such as microplates and abyssal hill fabric.

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