A case study of convectively sourced water vapor observed in the overworld stratosphere over the United States Academic Article uri icon


  • 2017. American Geophysical Union. All Rights Reserved. On 27 August 2013, during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys field mission, NASA's ER-2 research aircraft encountered a region of enhanced water vapor, extending over a depth of approximately 2km and a minimum areal extent of 20,000km2 in the stratosphere (375K to 415K potential temperature), south of the Great Lakes (42N, 90W). Water vapor mixing ratios in this plume, measured by the Harvard Water Vapor instrument, constitute the highest values recorded in situ at these potential temperatures and latitudes. An analysis of geostationary satellite imagery in combination with trajectory calculations links this water vapor enhancement to its source, a deep tropopause-penetrating convective storm system that developed over Minnesota 20h prior to the aircraft plume encounter. High resolution, ground-based radar data reveal that this system was composed of multiple individual storms, each with convective turrets that extended to a maximum of ~4km above the tropopause level for several hours. In situ water vapor data show that this storm system irreversibly delivered between 6.6kt and 13.5kt of water to the stratosphere. This constitutes a 2025% increase in water vapor abundance in a column extending from 115hP to 70hPa over the plume area. Both in situ and satellite climatologies show a high frequency of localized water vapor enhancements over the central U.S. in summer, suggesting that deep convection can contribute to the stratospheric water budget over this region and season.

published proceedings


author list (cited authors)

  • Smith, J. B., Wilmouth, D. M., Bedka, K. M., Bowman, K. P., Homeyer, C. R., Dykema, J. A., ... Anderson, J. G.

complete list of authors

  • Smith, Jessica B||Wilmouth, David M||Bedka, Kristopher M||Bowman, Kenneth P||Homeyer, Cameron R||Dykema, John A||Sargent, Maryann R||Clapp, Corey E||Leroy, Stephen S||Sayres, David S||Dean-Day, Jonathan M||Bui, T Paul||Anderson, James G

publication date

  • January 1, 2017 11:11 AM