Airborne DIAL Ozone and Aerosol Trends Observed at High Latitudes

• Main Authors: Over North America, Johnathan W. Hair, Edward V. Browell, Carolyn F. Butler, William B. Grant, Russell J, Marta A. Fenn, Vince G. Brackett, Marian B. Clayton, Lorraine A. Brasseur
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Tropospheric Ozone Production About the Spring Equinox
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.7.3520; http://techreports.larc.nasa.gov/ltrs/PDF/2002/mtg/NASA-2002-21ilrc-jwh.pdf

Ozone (O 3 ) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight aircraft flights over seven aircraft deployments covering the latitudes of 40 N between 4 February and 23 May 2000 as part of the TOPSE (Tropospheric Ozone Production about the Spring Equinox) field experiment. The remote and in situ O 3 measurements were used together to produce a vertically-continuous O 3 profile from near the surface to above the tropopause. Ozone, aerosol, and potential vorticity (PV) distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. The number of observed pollution plumes was found to increase into the spring along with a significant increase in aerosol loading. Ozone was found to increase in the middle free troposphere (4-6 km) at high latitudes (60 N) by an average of 4.3 ppbv/mo from about 55 ppbv in early February to over 72 ppbv in mid-May. The average aerosol scattering ratios in the same region increased at an average rate of 0.37/mo from about 0.35 to over 1.7. Ozone and aerosol scattering were highly correlated over entire field experiment. Based on the above results and the observed aircraft in-situ measurements, it was estimated that stratospherically-derived O 3 accounted for less than 20% of the observed increase in mid tropospheric O 3 at high latitudes. The primary cause of the observed O 3 increase was found to be the photochemical production of O 3 in pollution plumes.