Sea Surface and Ocean Temperature Observed from an Array of ASIS Buoys during the CLASI 2021 Field Campaign

Sea surface temperature (SST) is a key parameter in the atmosphere-ocean coupled system as a fundamental input to parameterizing interfacial heat flux. It is also important for estimating momentum flux through its role in governing the thermodynamic stability of the atmospheric boundary layer. In coastal environments, SST gradients at small spatial scales can strongly influence regional dynamics both above and below the ocean surface. Characterizing the persistence and strength of the gradients is necessary to environmental monitoring, prediction, and remote sensing of coastal environments. The Office of Naval Research sponsored the Coastal-Land-Air-Sea Interaction (CLASI) project to address the myriad of challenges to weather and climate forecast in the littoral zone. One of the objectives of CLASI is to understand and characterize the atmospheric boundary layer transition across the ocean and terrestrial land surfaces. As part of CLASI, a coordinated array of ocean and land-based measurement platforms was deployed between June and October 2021, in Monterey Bay, California. This included the largest deployment of the unique air-sea interaction spar (ASIS) buoy (8 total), a 15-m long surface-following buoy specifically designed to measure air-sea flux, near surface processes, and directional wave spectra. As part of this effort, three specially outfitted ASIS, the qT-ASIS, were equipped with additional sensors to measure near-surface vertical gradients of wind, air, and ocean temperature. These qT-ASIS were deployed in a cross-shore array during the entire Monterey Bay campaign. This presentation focuses on the processing and analysis of the radiometric SST observations collected via narrow banded pyrometer and a vertical array of self-logging thermistors mounted to the buoy frame and mooring line. The buoy SST was compared to a high-resolution global SST satellite product and revealed general agreement, as well as cases of strong cross-shore SST gradients. Further in-depth analysis into the SST and ocean temperature variability along this buoy line will be presented and discussed in the context of the satellite product validation, as well as implications for coastal air-sea interaction.