The VarDyn hybrid methodology, which combines minimal physically based constraints with a variational scheme, is demonstrated to enhance the mapping of sea surface height (SSH) and sea surface temperature (SST). By synthesizing multi-modal satellite observations, VarDyn produces SSH and SST maps with improved accuracy compared to operational products, achieving reductions in Root Mean Square Error and enhancements in effective spatial resolution. While most improvements are observed in highly energetic ocean regions, SSH map accuracy also improves slightly in low-energy regions—a significant advancement over other methods. VarDyn SSH fields and the associated geostrophic velocities show strong agreement with newly available high-resolution instantaneous SWOT estimates. Notably, the assimilation of SST proves particularly beneficial for SSH reconstruction when only two altimeters are available. The VarDyn methodology potentially offers a robust framework for refining climate SSH records by jointly assimilating SSH data from two altimeters and SST data from microwave sensors.

Key Points

VarDyn is a method using reduced physical models and a variational scheme to map sea surface height (SSH) and sea surface temperature (SST) from altimetric and microwave satellite data

Tested against recent high-resolution data, VarDyn improves the accuracy of SSH and SST maps compared to operational products

SSH mapping especially benefits from SST for a two altimeters configuration, opening the way of refining climate SSH records

Plain Language Summary

By combining fundamental physical principles with advanced data processing techniques, the joint reconstruction of sea surface height (SSH) and sea surface temperature (SST) is demonstrated. Using satellite data, this approach systematically produces more accurate SSH and SST maps, with particularly noticeable improvements in highly dynamic ocean regions. Additionally, the method significantly enhances mapping performance in calmer ocean areas. The results align closely with new high-resolution satellite observations. Notably, when only two altimeter satellites are available, incorporating SST data significantly improves SSH mapping capabilities. This methodology offers a promising tool for refining climate records by consistently integrating previously available medium-resolution SST and altimeter measurements.