Blending 2D topography images from SWOT into the altimeter constellation with the Level-3 multi-mission DUACS system

Abstract. The Surface Water and Ocean Topography (SWOT) mission delivers unprecedented swath altimetry products. Despite SWOT’s 2D coverage and precision, its Level-2 products suffer from the same limitations as their counterparts from nadir altimetry missions. Level-2 products are designed in a standalone ground-segment to meet the mission’s primary science objectives. In contrast, some research domains and applications require consistent multi-mission observations such as the Level-3 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.