Observations from MACPEX of enhanced chemical plumes and perturbations in tropopause structure in regions with deep convection

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Wednesday, 7 January 2015: 10:45 AM
124A (Phoenix Convention Center - West and North Buildings)
Gretchen L. Mullendore, Univ. of North Dakota, Grand Forks, ND; and B. C. Bigelbach, L. E. Christensen, J. J. Metz, and K. Pinkney
Manuscript (1.4 MB)

Deep convection, such as the severe thunderstorms observed throughout the United States in the spring and summer months, is an efficient transporter of gases, both anthropogenic and natural, from the boundary layer to the upper-tropospheric/lower-stratospheric region (UTLS). Of particular interest is mixing of boundary layer air directly into the stratosphere, but troposphere to stratosphere exchange (TSE) is uncertain in observations of active deep convection because the highly perturbed state of the tropopause makes quantifying irreversible transport difficult. During the NASA 2011 MACPEX mission, JPL in situ instruments aboard the WB57 aircraft provided valuable measurements of UTLS chemical plumes downwind of deep convection in the US Southern Great Plains and Southeast. Enhanced carbon monoxide plumes were identified from in situ vertical profiles, and back trajectories and observations of precipitation were used to verify which plumes had a recent convective source. The tropopause structure in the vicinity of each plume was then analyzed using aircraft data and categorized as a weak inversion, a strong inversion, or a double tropopause. These tropospheric structures were then compared to the regional environmental profiles obtained from radiosondes and reanalysis data. Preliminary results show the majority of analyzed plumes show double tropopause structures, which may enhance TSE.