Energy Sinks for Lee Waves in the Northern South China Sea

Abstract

AbstractRecent observations report a discrepancy between observed energy dissipation rates and lee wave pressure flux predicted by linear theory in the Southern Ocean, raising the possibility that wave energy re‐absorption by mean flows may be an important route to wave energy sink. Here we investigate the sink of lee waves in the northern South China Sea in a high‐resolution nested model initialized with a synthetically‐generated rough topography. Our results indicate that wave dissipation is the dominant sink of lee wave energy, with wave energy re‐absorption being of secondary importance. The dominant direction of energy transfer is from mean flows to lee waves through vertical shear and horizontal strain of mean flows. A series of idealized experiments suggest that the weak wave energy re‐absorption in the northern South China Sea is primarily due to the large Froude number there.