Seasonal variation of tropospheric ozone in Indonesia revealed by 5-year ground-based observations

Regular ozonesonde observation and total ozone observation with the Brewer spectrophotometehra ve been conducteda t Watukosek( 7.5øS, 112.6øE), Indonesia, since 1993. Three seasons are recognized for the vertical distribution of tropospherico zone. (1) During the local wet seasonb, etweenD ecembera nd March, the ozone mixing ratio is nearly constant at 25 ppbv throughout the troposphere. (2) During the transition season from wet to dry, between April and July, the mixing ratio is often enhancedin the uppermostt roposphere.( 3) During the local dry season, between August and November, the concentration is enhanced in the planetary boundary layer, and extensive forest fires in Indonesia associated with the strong E1 Nifio events of 1994 and of 1997 have enhanced the ozone mixing ratio in the middle troposphere, the integrated tropospheric ozone, and the total ozone at Watukosek