Improved Vorticity Balance in Gridded Altimetry Data from Multiple Satellites
Improved Vorticity Balance in Gridded Altimetry Data from Multiple Satellites
Abstract:
Multiple Satellite altimeters in orbit provide along-track measurements of sea surface height (SSH) that has a resolution of ~ 60 km. However, data need to be mapped to a regular space-time grid for a wide range of scientific analyses. The methodologies that have been used for producing gridded SSH include optimal interpolation (OI) and two-dimensional variational mapping method (2-Dvar). Analyses showed that vorticities in the existing data product are not in desirable balance. The present study proposes new methods to constrain vorticity balance in a 2-Dvar system. The constraint is integrated into the 2-Dvar through the background state and associated error covariance and a weak dynamical constraint based on the quasi-geostrophic vorticity balance equation. We will present the gridded SSH data with improved vorticity balance for East China Sea.