Improved global sea surface height and current maps from remote sensing and in situ observations

[摘要] We present a new gridded sea surface height and current datasetproduced by combining observations from nadir altimeters and drifting buoys.This product is based on a multiscale and multivariate mapping approachthat offers the possibility to improve the physical content of griddedproducts by combining the data from various platforms and resolving abroader spectrum of ocean surface dynamic than in the current operationalmapping system. The dataset covers the entire global ocean and spans from1 July 2016 to 30 June 2020. The multiscale approachdecomposes the observed signal into different physical contributions. In thepresent study, we simultaneously estimate the mesoscale ocean circulationsas well as part of the equatorial wave dynamics (e.g. tropical instabilityand Poincaré waves). The multivariate approach is able to exploit thegeostrophic signature resulting from the synergy of altimetry and drifterobservations. Sea-level observations in Arctic leads are also used in themerging to improve the surface circulation in this poorly mapped region. Aquality assessment of this new product is proposed with regard to anoperational product distributed in the Copernicus Marine Service. We showthat the multiscale and multivariate mapping approach offers promisingperspectives for reconstructing the ocean surface circulation:observations of leads contribute to improvement of the coverage in delivering gap-free mapsin the Arctic and observations of drifters help to refine the mapping in regionsof intense dynamics where the temporal sampling must be accurate enough toproperly map the rapid mesoscale dynamics. Overall, the geostrophiccirculation is better mapped in the new product, with mapping errorssignificantly reduced in regions of high variability and in the equatorialband. The resolved scales of this new product are therefore between 5 %and 10 % finer than the Copernicus product ( https://doi.org/10.48670/moi-00148 , Pujol et al., 2022b).

[学科分类] 眼科学