MODULATION OF TROPOSPHERIC OZONE BY A PROPAGATING GRAVITY-WAVE

The modulation of tropospheric ozone by a propagating gravity wave is inferred from the analysis of more than 200 lidar profiles obtained ov er a 14-hour period during September 3-4, 1993, near Rollinsville, Col orado (39.9 degrees N, 105.3 degrees W, 2.68 km msl). Periodic fluctua tions of up to 30% in the ozone mixing ratios are attributed to a near ly monochromatic gravity wave with a downward phase velocity of -0.08 +/- 0.01 m s(-1), a mean vertical wavelength of 3.0 +/- 0.5 km, and an apparent frequency of(1.7 +/- 0.4) x 10(-4) s(-1). Wind profiles from nearby radar soundings suggest that these fluctuations are induced by a gravity wave that propagates from the NW to SE with a horizontal wa velength of similar to 180 km. These results imply that gravity waves may contribute significantly to the short-term (less than or equal to 1 day) variability of ozone and other trace gases in the troposphere.