INTERGEO Agenda - english

Coral reefs, among the most fragile ecosystems on Earth, play a critical role as natural barriers against incoming waves while simultaneously being threatened by climate-change-related processes such as ocean warming, ocean acidification, sea-level rise, and changing storm patterns. Satellite altimetry offers the opportunity to monitor coral reefs on the global scale, although coastal environments remain much more challenging to observe than the open ocean because of signal-processing limitations. In this work, we analyze two complementary data sources for this purpose. First, we use the ESA Sea State Climate Change Initiative (Sea State CCI) dataset, which is based on a multi-mission, cross-calibrated archive spanning more than two decades of observations and processed using state-of-the-art standards to improve the quality and coverage of coastal data. Second, we investigate the quality of the two-dimensional significant wave height observations provided by the SWOT mission, the first satellite altimetry mission to employ swath interferometry. To assess the added value of SWOT observations, we compare SWOT and Sentinel-6 data acquired during their coincident time span. This allows us to evaluate the limitations of conventional along-track altimetry in measuring wave attenuation across coral reefs, as well as the potential gains in spatial understanding enabled by the improved coverage provided by swath interferometry. At the same time, the analysis of long-term records from the ESA Sea State CCI dataset may provide further insight into whether changes in coral reef extent and structural complexity can be detected through variations in their effectiveness at wave attenuation.