Observing Bulk Meteorological Parameters and Air–Sea Heat Fluxes with a Spotter Buoy

Air–sea heat fluxes play a key role in coupled oceanic–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 the 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. SIGNIFICANCE STATEMENT: One of the primary ways that the ocean and atmosphere interact is by exchanging heat across the ocean surface. This heat transfer is important to measure and understand because it affects both shortterm weather and long-term climate. Unfortunately, technological limitations have historically limited our ability to measure this heat transfer. In this paper, we describe a new method that combines low-cost, easy-to-use sensors with physics-based and data-driven models to infer key atmospheric variables, which in turn allows the estimation of the magnitude and direction of heat transfer between the ocean and atmosphere. This technological advance could pave the way for widespread, real-time observations of oceanic–atmospheric heat exchange.