A Cavity-Enhanced UV Absorption Instrument for High Precision, Fast Time Response Ozone Measurements

Abstract

Abstract. The NASA Rapid Ozone Experiment (ROZE) is a broadband cavity-enhanced UV absorption instrument for the detection of in situ ozone (O3). ROZE uses an incoherent LED light source coupled to a high-finesse optical cavity to achieve an effective pathlength of ~ 104 m. Due to its high-sensitivity and small optical cell volume, ROZE demonstrates a 1σ precision of 80 pptv (0.1 s) and 31 pptv (1 s), as well as a 1/e response time of 50 ms. ROZE can be operated in a range of field environments, including low- and high-altitude research aircraft, and is particularly suited to O3 vertical flux measurements using the eddy covariance technique. ROZE was successfully integrated aboard the NASA DC-8 aircraft during July–September 2019 and validated against a well-established chemiluminescence measurement of O3. A flight within the marine boundary layer also demonstrated flux measurement capabilities, and we observed a mean O3 deposition velocity of 0.029 ± 0.005 cm s–1 to the ocean surface. The performance characteristics detailed below make ROZE a robust, versatile instrument for field measurements of O3.