The Impact of Barrier Layers on Arabian Sea Surface Temperature Variability

Abstract

Barrier layers (BLs) in the Arabian Sea may lead to increased mixed layer (ML) warming or cooling relative to non-BL conditions, depending on differences in ML properties and atmospheric forcing. We use 13 years of profiling float data from the Arabian Sea to identify when and where each impact is likely based on analysis of the ML temperature tendency. We use a novel method based on the vertical spice profile to identify BLs and their characteristics. BLs are most likely to increase warming during the northeast monsoon, owing to temperature inversions, preceding the development of the miniwarm pool and onset of the southwest monsoon. This effect is nonuniform and is counteracted in some regions by increased penetration of solar radiation below the shallower ML associated with BL. Relative rates of cooling increase in the presence of BL during the southwest monsoon; intermonsoon periods show little net effect from BL.