북적도 해류 지역의 PIES 해면고도와 AVISO 위성 해면고도의 비교 연구

Abstract

Satellite-measured along-track and gridded sea surface height (SSH) anomaly products from AVISO are compared with in situ SSH anomaly measurements from an array of 4 pressure-recording inverted echo sounders (PIESs), which was deployed across the North Equatorial Current in the Western Pacific. PIESs measure bottom pressure (Pbot) and round-trip acoustic travel time from the sea floor to the sea surface (τ). The Pbot and τ measurements are used to estimate, respectively, the mass-loading and steric height variation in SSH anomaly. From Pbot and τ, it is revealed that the mass-loading component is relatively small in this region. Two sets of delayed-time SSH anomaly AVISO products are evaluated: (1) mono-mission Jason-2 along-track product with 9.92-day interval, and (2) “Reference” gridded products with 7-day interval using two satellites sampling from Jason-2 and Cryosat-2. Satellite-measured SSH anomaly, the variation of which is caused by westward-propagating mesoscale eddies and frontal fluctuations bordering subtropical- and tropical-gyres, agrees well with PIES-derived SSH anomaly. Our results confirm that satellite-measured SSH represents well the mesoscale physical processes around the North Equatorial Current.ss the North Equatorial Current in the Western Pacific. PIESs measure bottom pressure (Pbot) and round-trip acoustic travel time from the sea floor to the sea surface (τ). The Pbot and τ measurements are used to estimate, respectively, the mass-loading and steric height variation in SSH anomaly. From Pbot and τ, it is revealed that the mass-loading component is relatively small in this region. Two sets of delayed-time SSH anomaly AVISO products are evaluated: (1) mono-mission Jason-2 along-track product with 9.92-day interval, and (2) “Reference” gridded products with 7-day interval using two satellites sampling from Jason-2 and Cryosat-2. Satellite-measured SSH anomaly, the variation of which is caused by westward-propagating mesoscale eddies and frontal fluctuations bordering subtropical- and tropical-gyres, agrees well with PIES-derived SSH anomaly. Our results confirm that satellite-measured SSH represents well the mesoscale physical processes around the North Equatorial Current.