FIELD OBSERVATIONS OF THE VERTICAL-DISTRIBUTION OF TROPOSPHERIC OZONEAT THE ISLAND OF REUNION (SOUTHERN TROPICS)

Citation
S. Baldy et al., FIELD OBSERVATIONS OF THE VERTICAL-DISTRIBUTION OF TROPOSPHERIC OZONEAT THE ISLAND OF REUNION (SOUTHERN TROPICS), JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 101(D19), 1996, pp. 23835-23849
Citations number
37
Categorie Soggetti
Metereology & Atmospheric Sciences
Volume
101
Issue
D19
Year of publication
1996
Pages
23835 - 23849
Database
ISI
SICI code
Abstract
An analysis of 1 year of tropospheric vertical soundings of ozone at t he island of Reunion (21 degrees S, 55 degrees E) is presented. High v alues of ozone concentration are observed in the troposphere above the inversion level that caps the marine boundary layer (MEL) during the September to November period, concomitant with active biomass burning in the southeastern African continent and Madagascar. Tongues (promine nces of higher values) of enhanced ozone are apparent on vertical prof iles obtained during this period, and backward trajectories from tongu e levels are generally traced back to these zones of intense burning. Profiles of high and almost constant ozone mixing ratio in the whole t roposphere above the MBL are also obtained during this season and coul d not be traced back to a definite origin. Conversely, during January to March, MEL. compounds and humidity are convected in the whole tropo sphere, and tropospheric ozone is very low. The seasonal variation of integrated tropospheric ozone is large, up to 30 Dobson units (DU) and the tropospheric contribution to total columnar ozone could be high, up to 50-55 DU. This seasonal variation is well correlated with total ozone mapping spectrometer (TOMS) data, anticorrelated with integrated water content, and approximately follows, with a small time lag, the seasonal fire activity in the southeastern Africa, Data from Reunion a re in accord with equivalent results from Ascension Island (8 degrees S, 15 degrees W), Brazzaville (Congo; 4 degrees S, 15 degrees E) and N atal (Brazil; 6 degrees S, 35 degrees W), corroborate satellite observ ations, and suggest that the concentration of tropospheric ozone in th e tropics is governed by the coupling of photochemical and dynamical p rocesses.