Ozone deposition velocity measurements over the ocean using a new fast, high-precision instrument

Abstract:

The NASA Rapid Ozone Experiment (ROZE) is a cavity-enhanced ultraviolet absorption instrument for in-situmeasurements of ozone (O₃). The high-sensitivity and small sample volume of the optical cell enable high-precision measurements in short integration times (~30 pptv s^–1), making this instrument suitable for O₃vertical flux measurements via the eddy covariance technique. The compact, nearly autonomous instrument design also supports operation in a range of field environments, including low- and high-altitude aircraft platforms. FIREX-AQ provided the first field demonstration of ROZE, which flew on the NASA DC-8 aircraft. We report on instrument design and performance, including validation against the NOAA NO_yO₃chemiluminescence O₃ measurement. We also describe O₃ flux observations using eddy covariance analysis from a flight with several low-level legs over the coastal Pacific Ocean. Our results demonstrate sufficient instrument precision and time response for sensitive measurements of O₃ deposition velocities, with potential future applications in constraining oceanic and terrestrial ozone deposition processes.