whigg/wave_climatology

Research article in progress: The Seasonal Cycle of Significant Wave Height in the Ocean: Local vs Remote Forcing

Abstract

Significant wave height (SWH) provides insight about the interactions between the ocean and the atmosphere. In the Northern and Southern Hemispheres, wave heights have been observed to undergo an annual sinusoidal cycle in response to seasonal changes in storm patterns. In the California coast region, local expansion fan wind events lead to deviations in significant wave height during boreal spring and summer. Other coastal regions where supercritical channel flows occur due to coastal topography and atmospheric forcing during the early summer months include eastern boundary regions of ocean basins, the south Caribbean, and West Arabian Sea. Here, intraannual variability of surface gravity waves is analyzed globally in SWH and wind speed data, using over two decades of satellite-derived SWH and wind data. The location at which surface waves are generated is used for validation of mechanisms driving wave characteristics. Phasing of the SWH seasonal cycle reveals that the primary hemisphere dominating the wave field has an abrupt and rough boundary through the equatorial region due in part to topography causing shadowing of waves. In summer wind anomaly (SWA) regions, the fraction of wave variability attributed to local wind events varies depending on local conditions. Global maps of probability of swell based on wave age confirm that wind anomaly regions typically have locally forced waves during the spring and summer months.

Authors

• Luke Colosi<[email protected]>
• Bia Villas Boas <[email protected]>
• Sarah T. Gille

Data

Altimetry Data

WaveWatch III Hindcast forced with CFSR Winds

Buoy Data