The Office of Naval Research's Coupled Boundary Layers and Air–Sea Transfer (CBLAST) program is being conducted to investigate the processes that couple the marine boundary layers and govern the exchange of heat, mass, and momentum across the air–sea interface. CBLAST-LOW was designed to investigate these processes at the low-wind extreme where the processes are often driven or strongly modulated by buoyant forcing. The focus was on conditions ranging from negligible wind stress, where buoyant forcing dominates, up to wind speeds where wave breaking and Langmuir circulations play a significant role in the exchange processes. The field program provided observations from a suite of platforms deployed in the coastal ocean south of Martha's Vineyard. Highlights from the measurement campaigns include direct measurement of the momentum and heat fluxes on both sides of the air–sea interface using a specially constructed Air–Sea Interaction Tower (ASIT), and quantification of regional oceanic variability over scales of O(1–104 mm) using a mesoscale mooring array, aircraft-borne remote sensors, drifters, and ship surveys. To our knowledge, the former represents the first successful attempt to directly and simultaneously measure the heat and momentum exchange on both sides of the air–sea interface. The latter provided a 3D picture of the oceanic boundary layer during the month-long main experiment. These observations have been combined with numerical models and direct numerical and large-eddy simulations to investigate the processes that couple the atmosphere and ocean under these conditions. For example, the oceanic measurements have been used in the Regional Ocean Modeling System (ROMS) to investigate the 3D evolution of regional ocean thermal stratification. The ultimate goal of these investigations is to incorporate improved parameterizations of these processes in coupled models such as the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) to improve marine forecasts of wind, waves, and currents.

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University of Connecticut, Avery Point, Groton, Connecticut

NOAA/ARL, Idaho Falls, Idaho

FPL Energy, Juno Beach, Florida

Woods Hole Oceanographic Institution, Woods Hole, Massachusetts

University of Athens, Athens, Greece

Johns Hopkins University, Baltimore, Maryland

University of California, Irvine, California

Applied Physics Laboratory, University of Washington, Seattle, Washington

CIRPAS, Monterey, California

Center for Environmental Sciences, University of Maryland, Cambridge, Maryland

Oregon State University, Corvallis, Oregon

Lamont Doherty Earth Observatory, Columbia University, Palisades, New York

Naval Postgraduate School, Monterey, California

National Center for Atmospheric Research, Boulder, Colorado

Naval Research Laboratory, Monterey, California

Rutgers University, New Brunswick, New Jersey

Massachusetts Institute of Technology, Cambridge, Massachusetts