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

I. Kilbane-dawe et al., 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, J ATMOS CH, 39(2), 2001, pp. 123-138
Citations number
Categorie Soggetti
Environment/Ecology,"Earth Sciences
Journal title
ISSN journal
0167-7764 → ACNP
Year of publication
123 - 138
SICI code
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 wit h 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 J anuary as observed. SLIMCAT underestimates the loss rates observed in Febru ary and March by 1-3 ppbv/sunlit hour. By the end of March, SLIMCAT ozone e xceeds the observations by 25-35%. In January 1995 the ozonesonde-derived l oss 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 for cing data significantly improved the agreement between the model and observ ed ozone at the end of winter 1994/95, increasing ozone destruction in SLIM CAT in February and March. The SLIMCAT simulation of winter 1995/96 does no t reproduce the maximum ozone loss rates diagnosed by Match of 13 ppbv/sunl it hour. Comparing the data for the two winters reveals that the SLIMCAT ph otochemistry is least able to reproduce observed losses at low temperatures or when low temperatures coincide with high solar zenith angles (SZA). Whe n cold (T = 192 K), high SZA (greater than or equal to 90 degrees) 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 t he rest of the winter SLIMCAT consistently underestimates the Match rates o f ozone loss by 1-3 ppbv/sunlit hour. In March 1996 the monthly mean SLIMCA T ozone is 50% greater than observations at 430-540 K. In both winters, ozo ne destruction rates peaked more rapidly and declined more slowly in the Ma tch observations than in the SLIMCAT simulations. The differences between t he observed and modelled cumulative ozone losses demonstrate that the total ozone destruction by the end of the winter is sensitive to errors in the i nstantaneous ozone loss rates of 1-3 ppbv/sunlit hour.