DATA FUSION OF SEA SURFACE HEIGHT ANOMALY FROM HY-2A AND JASON-2

Altimeter provides a unique perspective to observe global ocean frequently which is never happened before. Whereas the altimeter measures the ocean in a narrow track, it is inconvenient in studying the ocean structures such as Kuroshio and Gulf Stream, let alone the mesoscale structures which are important ways to transport mass and energy. These ocean structures determined by sea surface topography (SST) can be estimated using altimeter data. In this study, we present a fusion result of altimetry data by combining HY-2A and Jason-2. The merged data, generated using optimal interpolation (OI), present a detailed description for mesoscale structures in Kuroshio area. In this study, (1) altimetry data for both HY-2A and Jason-2 employed to determine sea surface height anomaly (SSHA) are corrected using collected independent source including European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data, TPXO ocean tide model etc. (2) in order to further enrich the details of mesoscale structures, altimetry data from other ongoing mission including Cryosate-2 and SARAL/Altika are take into account. (3) to ensure accuracy of the fusion, observation bias of sea surface heights from HY-2A are corrected to align with the reference mission Jason-2 using cross-calibration, since Jason-2 have been calibrated stringently. The relative biases for HY-2A, SARAL/Altika and Cryosate-2 are 37.36cm, -4.54cm and -72.5cm and the corresponding standard deviations are 5.58cm, 5.26cm and 5.02 cm respectively, which suggest accurate observations and reliable reprocessing. (4) optimal interpolation is used to perform the interpolation, thus generate SSHA with grid format which are easy to distinguish the mesoscale structures. (5) more details are introduced from multi-missions rather than one.