On the Impact of High-Frequency Wind Variability on Upper Ocean Stratification

Abstract:

Projections of future climate are sensitive to the representation of upper ocean variability on subseasonal-to-seasonal time scales. Our understanding of air-sea interactions requires a robust characterization of high-frequency wind variability, associated with storms and gusty or intermittent winds. The interaction of high-frequency winds and surface buoyancy fluxes can drive variations in mixed-layer depth and turbulent mixing relevant to ocean heat uptake and biogeochemistry. Recent studies have shown that high-frequency wind variability plays a dominant role in governing the evolution of upper ocean temperature and that representing this wind variability as a stochastic signal realistically reproduces observations (i.e., the fact that gusty wind is present matters more than its details). The surface mooring from the Ocean Observatories Initiative (OOI) Global Southern Ocean Array (54°S, 89°W) provides repeated meteorological measurements of high-latitude winds at high temporal resolution from which we can evaluate wind statistics. In this study, we use OOI mooring data and a one-dimensional process model to explore the impact of high-frequency stochastic winds on upper ocean stratification. Results presented here have bearing on the calibration, validation, and future planning of wind satellite observations as well as offering the potential to inform an improved representation of upper ocean processes in climate models.