Wide-swath satellite altimetry unveils an unprecedented panorama of oceanic internal gravity waves

As pervasive carriers of mechanical energy through the stratified ocean, internal gravity waves (IGWs) regulate global circulation and Earth’s climate via driving diapycnal mixing. Yet, obtaining a basin-wide, full-spectrum view of IGWs has long been impractical in the real ocean, as it demands high-resolution observations across vast scales. The recently-launched Surface Water and Ocean Topography (SWOT) satellite mission provides unprecedented two-dimensional, kilometer-scale sea surface height measurements, opening up the possibility. Here, we develop a deep learning model to extract IGWs signals from SWOT measurements. The extracted IGWs constitute the first observation-based panorama over the South China Sea, which represents a prime example of intense wave activities. This panoramic quantification is at least two times larger in magnitude than what was previously available with conventional satellite altimetry for most part of the study region. This breakthrough unlocks SWOT’s potential for studying IGWs and their role in global circulation and climate.