How HY-2A/GM altimeter performs in marine gravity derivation: Assessment in the South China Sea

Chengcheng Zhu, Jinyun Guo*, Cheinway Hwang, Jinyao Gao, Jiajia Yuan, Xin Liu

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

HY-2A is China?s first satellite altimeter mission, launched in Aug. 2011. Its geodetic mission (GM) started from 2016 March 30 till present, collecting sea surface heights for about five 168-d cycles. To test how the HY-2A altimeter performs in marine gravity derivation, we use the least-squares collocation method to determine marine gravity anomalies on 1′ × 1′ grids around the SouthChina Sea (covering 0°?30°N, 105°E?125°E) from theHY-2A/GM-measured geoid gradients.We assess the qualities of theHY-2A/GM-derived gravity over different depths and areas using the bias and tilt-adjusted ship-borne gravity anomalies from the U.S. National Centers for Environmental Information (NCEI) and the Second Institute of Oceanography, Ministry of Natural Resources (MNR) of P. R. China. The RMS difference between the HY-2A/GM-derived and the NCEI ship-borne gravity is 5.91 mGal, and is 5.33 mGal when replacing the HY-2A value from the Scripps Institution of Oceanography (SIO) V23.1 value. The RMS difference between the HY-2A/GM-derived and the MNR ship-borne gravity is 2.90 mGal, and is 2.76 mGal when replacing the HY-2A value from the SIO V23.1 value. The RMS difference between the HY-2A and SIO V23.1 value is 3.57 mGal in open sea areas at least 20 km far away from the coast. In general, the difference between the HY-2A/GMderived gravity and ship-borne gravity decreases with decreasing gravity field roughness and increasing depth. HY-2A results in the lowest gravity accuracy in areas with islands or reefs. Our assessment result suggests thatHY-2A can competewith otherKu-band altimeter missions in marine gravity derivation.

Original languageEnglish
Pages (from-to)1056-1064
Number of pages9
JournalGeophysical Journal International
Volume219
Issue number2
DOIs
StatePublished - 26 Jul 2019

Keywords

  • Asia
  • Gravity anomalies and Earth structure
  • Inverse theory
  • Satellite geodesy

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