High-Latitude Tropospheric Ozone, Aerosol, and Potential Vorticity Trends Observed from February to May 2000 During the TOPSE Field Experiment
Abstract
An airborne UV Differential Absorption Lidar (DIAL) system was flown on the NCAR (National Center for Atmospheric Research) C-130 aircraft on seven deployments covering the latitudes of 40N-85N on 38 flights between 5 February and 23 May 2000 as part of the TOPSE (Tropospheric Ozone Production about the Spring Equinox) field experiment. Each deployment started from Broomfield, Colorado, with bases in Churchill, Manitoba, Canada, and on most deployments, Thule, Greenland. Ozone profiles, which were derived from DIAL lidar returns at 289 and 300 nm, and aerosol scattering ratio profiles, which were derived from lidar returns at 1064 nm, were measured simultaneously above and below the aircraft to obtain nearly complete profiles from near the surface to above the tropopause along the aircraft flight track. In situ measurements on the aircraft were used in combination with the nadir and zenith DIAL ozone measurements to produce a vertically-continuous ozone profile across the troposphere. Potential vorticity (PV) distributions along the flight track were obtained from the analyses of several meteorological models with different resolutions. Ozone, aerosol, and PV distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. The number of observed pollution plumes increased into the spring along with an increase in aerosol loading. Stratospheric intrusions were observed on 21 of the TOPSE flights with a higher frequency of occurrences observed near the end of the field experiment. Ozone was found to increase in the free troposphere (2-5 km) at high latitudes (60-85N) by an average of 3.2 ppbv/month starting in early February to over 60 ppbv in mid-May. Most of the ozone increase was found to be in April and early May when the rate of increase was found to be 4.6 ppbv/month. Extensive regions of very low ozone were observed near the surface, which was attributed to bromine chemistry. Trends in ozone, aerosols, and PV distributions from various models were determined as a function of latitude and altitude over the period of the TOPSE field experiment, and the correlation in these results are used to estimate the relative contribution of transport and photochemistry to the ozone change at high-latitudes over the period of this experiment.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM...A22B03B
- Keywords:
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- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0305 Aerosols and particles (0345;
- 4801);
- 0325 Evolution of the atmosphere;
- 0365 Troposphere--composition and chemistry;
- 0368 Troposphere--;
- onstituent transport and chemistry