Blending 2D topography images from the Surface Water and Ocean Topography (SWOT) mission into the altimeter constellation with the Level-3 multi-mission Data Unification and Altimeter Combination System (DUACS)

The Surface Water and Ocean Topography (SWOT) mission delivers unprecedented swath-altimetry products. Despite SWOT's 2D coverage and precision, its Level-2 ocean products suffer from the same limitations as their counterparts from nadir altimetry missions. To achieve the mission's primary science objectives, the space agencies generate Level-2 ocean products with SWOT alone. In contrast, some research domains and applications require consistent multi-mission observations, such as the Level-3 ocean products provided by the Data Unification and Altimeter Combination System (DUACS) for almost 3 decades and with 20 different satellites. In this paper, we describe how we extended the Level-3 algorithms to handle SWOT's unique swath-altimeter data. We also illustrate and discuss the benefits, relevance, and limitations of Level-3 swath-altimeter products for various research domains.