Sea surface height variability from satellite altimetry and pressure-recording inverted echo sounders in the north equatorial current region

Abstract

An array of 4 pressure-recording inverted echo sounders (PIESs) was deployed across the North Equatorial Current (NEC) in the Northwestern Pacific Equatorial (NPE) region. The PIES measures bottom pressure and round-trip acoustic travel time from the sea floor to the sea surface. The mass-loading and steric height variations in sea surface height (SSH) anomaly are estimated with the bottom pressure and round-trip acoustic travel time measurements, respectively. In situ SSH anomaly measurements from the PIESs are compared with three sets of satellite-measured SSH anomaly products from AVISO, mono-mission and multi-mission along-track delayed-time products and reference merged (gridded) delayed-time product (Ref-MSLA). Out of the three AVISO products, Ref-MSLA shows the best match with PIES-derived SSH anomaly in the range of 0.68 to 0.78 correlations. Outstanding error-reduced results in Ref-MSLA are accounted for the merging process conducted by AVISO. This work suggests that Ref-MSLA is the preferable data set to investigate the SSH variability in the NPE region than along-track products.e from the sea floor to the sea surface. The mass-loading and steric height variations in sea surface height (SSH) anomaly are estimated with the bottom pressure and round-trip acoustic travel time measurements, respectively. In situ SSH anomaly measurements from the PIESs are compared with three sets of satellite-measured SSH anomaly products from AVISO, mono-mission and multi-mission along-track delayed-time products and reference merged (gridded) delayed-time product (Ref-MSLA). Out of the three AVISO products, Ref-MSLA shows the best match with PIES-derived SSH anomaly in the range of 0.68 to 0.78 correlations. Outstanding error-reduced results in Ref-MSLA are accounted for the merging process conducted by AVISO. This work suggests that Ref-MSLA is the preferable data set to investigate the SSH variability in the NPE region than along-track products.