A comparison of Match ozonesonde-derived and 3D model ozone loss rates in the Arctic polar vortex during the winters of 1994/95 and 1995/96

• Published in: Journal of atmospheric chemistry Vol. 39; no. 2; pp. 123 - 138
• Main Authors: KILBANE-DAWE, I, HARRIS, N. R. P, PYLE, J. A, REX, M, LEE, A. M, CHIPPERFIELD, M. P
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.06.2001; Springer Nature B.V
• Subjects: Arctic; Atmospheric chemistry; Atmospheric composition. Chemical and photochemical reactions; Earth, ocean, space; Exact sciences and technology; External geophysics; Low temperature; Ozone; Photochemistry; Physics of the high neutral atmosphere; Vortices; Arctic Region; Arctic; Polar vortex; Three dimensional model; Winter; Stratosphere; Loss rate; Observation data; Ozone; Numerical simulation; Comparative study
• ISSN: 0167-7764; 1573-0662
• DOI: 10.1023/A:1010607521870

Ozone loss rates from ozonesonde data reported in the Match experiments of winters 1994/95 and 1995/96 inside the Arctic polar vortex are compared with simulations of the same winters performed using the SLIMCAT 3D chemistry and transport model. For 1994/95 SLIMCAT reproduces the location and timing of the diagnosed ozone destruction, reaching 10 ppbv/sunlit hour in late January as observed. SLIMCAT underestimates the loss rates observed in February and March by 1-3 ppbv/sunlit hour. By the end of March, SLIMCAT ozone exceeds the observations by 25-35%. In January 1995 the ozonesonde-derived loss rates at levels above 525 K are not chemical in origin but due to poor conservation of air parcels. Correcting temperature biases in the model forcing data significantly improved the agreement between the model and observed ozone at the end of winter 1994/95, increasing ozone destruction in SLIMCAT in February and March. The SLIMCAT simulation of winter 1995/96 does not reproduce the maximum ozone loss rates diagnosed by Match of 13 ppbv/sunlit hour. Comparing the data for the two winters reveals that the SLIMCAT photochemistry is least able to reproduce observed losses at low temperatures or when low temperatures coincide with high solar zenith angles (SZA). When cold (T = 192 K), high SZA (≥90°)matches are excluded from the 1995/96 analysis, agreement between the diagnoses and SLIMCAT is better with ozone loss rates of up to 6 ppbv/sunlit hour. For the rest of the winter SLIMCAT consistently underestimates the Match rates of ozone loss by 1-3 ppbv/sunlit hour. In March 1996 the monthly mean SLIMCAT ozone is 50% greater than observations at 430-540 K. In both winters, ozone destruction rates peaked more rapidly and declined more slowly in the Match observations than in the SLIMCAT simulations. The differences between the observed and modelled cumulative ozone losses demonstrate that the total ozone destruction by the end of the winter is sensitive to errors in the instantaneous ozone loss rates of 1-3 ppbv/sunlit hour.[PUBLICATION ABSTRACT]