Observation of the Structure on Moving Gust Patterns Over a Water Surface (“Cat's Paws”)

Abstract

We report on observations of near-surface Velocity, temperature, stress, buoyancy, and surface wave fluctuations, including successive short-time averages of coherences, phases, autospectra, and probability densities of the variables. There appear to be short-duration events where the momentum exchange exceeds the average by 102. These events are characterized by the high energy content in capillary waves, and velocity and temperature fluctuations; they are separated by relatively quiesent periods. Energy transfer between components is discernible as is a tendency to logarithmico-normal distribution in the occurrence of measures of fluctuations.