Simultaneous Bro and Oclo Profile Measurements In The Arctic Vortex; Implications For The Clo and Bro Chemistry and Inferred Ozone Loss From The Clo/bro Ozone Loss Cycle
Abstract
During the EuroSolve campaign in winter 1999/2000, the LPMA/DOAS (Labora- toire de Physique Moleculaire et Applications/Differential Optical Absorption Spec- troscopy) balloon was lauched from Kiruna into the highly activated arctic vortex on Feb. 18, 2000. The azimuth-controlled balloon gondola carried three spectrometer, which performed solar occultation measurements in virtually at whole all wavelength from 320 nm into the mid-infrared. Line of sight absorption and profile of a suite of atmospheric gases (O3, NO2, BrO, OClO, IO, OIO, CH4, H2O, HCl, ClONO2, N2O,.....) were measured and compared with 3-D CTM and 1D trajectory models. The present paper reports on the simultaneous BrO, and OClO measurements. BrO concentrations of up 16.6+/-2 ppt - implying a total Bry of 23+/-2.5 ppt - , and OClO of up to 12+/-2 ppt (at 90 SZA) - implying ClOx = 1.8+/-0.2ppb - at 19 km were measured. These values are apparently compatible with the modeled and measured bromine and chlorine chemistry and budget. The BrO and OClO measurements allow us to infer ozone loss rates due to the ClO dimer cycle and the coupled BrO/ClO cy- cle, which are compared with inferred O3 loss rates. The OClO measured above 25 km (8+/- 2ppt), where NOx is found to be large (> 500 ppt), however, is much larger than what can be easily explained by present photochemistry. This finding points to a deficit in our understanding of the NOx/ClOx/BrOx coupling, a finding also reported previously from from SAOZ/LPMA and AMON. Various possibilites to solve that discrepancy and their potential for ozone chemistry will be discussed.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.2872D