Tides in complex coastal regions: early case studies from wide-swath SWOT measurements

Studying ocean tides with satellite altimetry has traditionally been difficult in coastal regions. The 1-day repeat of the Cal/Val phase of SWOT provides a unique dataset that can be exploited for tidal analysis. In this work, KaRIn data from the SWOT Cal/Val phase are analysed in two coastal regions to present a first look at the possibilities for tidal analysis from SWOT. The areas are: (1) Bristol Channel and (2) Great South Bay. When benchmarked against in situ measurements in these regions, substantial improvements over tide models, which typically report errors exceeding tens of centimetres and degrees, are seen. Specifically, the SWOT ocean products exhibit amplitude discrepancies ranging from 1.75 to 3 cm and phase lag discrepancies between 1.75 and 2.75 degrees when compared with in situ tide gauge data. These findings underscore the value of SWOT for tidal research in complex coastal regions.