Observing bulk meteorological parameters and air-sea heat fluxes with a Spotter buoy

Air-sea heat fluxes play a key role in coupled ocean-atmospheric processes, yet are challenging to measure at high density or scale due to technological constraints. To help fill this data gap, we developed a novel observational platform based on a simple modification to the Sofar Spotter, an off-the-shelf wave buoy. We applied both data-driven and physical models to map Spotter observations to ground-truth measurements collected at Martha’s Vineyard Coastal Observatory, thus enabling estimation of near-surface air temperature, which in turn allowed us to calculate Spotter-based sensible heat fluxes using established bulk flux parameterizations. Additional models were developed for estimating specific humidity, incoming shortwave radiation, and latent heat flux from Spotter data, though we expect that future hardware improvements will be necessary to move those models beyond the proof-of-concept stage. The sensible heat flux, however, had low bias relative to direct covariance observations, suggesting that low-cost buoys could serve as a viable source of distributed air-sea flux observations.