A134-08
Combining Remote Sensing Observations of Stratospheric Water Vapor with Lagrangian Transport Modelling and Measurements of Tropopause Overshooting Convection to Understand Stratospheric Water Injection Processes

Friday, 11 December 2020: 17:58
Virtual
Cody R Floerchinger, Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA, United States, John A Dykema, Harvard Univ, Cambridge, MA, United States, Jessica B Smith, Harvard Univ/Anderson Group, Cambridge, MA, United States, Corey Clapp, Harvard University, Chemistry and Chemical Biology, Cambridge, MA, United States, Kenneth Paul Bowman, Texas A&M Univ, College Station, TX, United States, John William Cooney, NPP/USRA Post-Doc at NASA Langley Research Center, Hampton, VA, United States, Kristopher M Bedka, NASA Langley Research Center, Climate Science Branch, Hampton, VA, United States and Frank N Keutsch, Harvard University, School of Engineering and Applied Sciences, Department of Chemistry and Chemical Biology, and Department of Earth and Planetary Sciences, Cambridge, MA, United States; Harvard University, Department of Chemistry and Chemical Biology, Cambridge, MA, United States
Recorded Presentation
Abstract:
Water vapor in the Upper Troposphere Lower Stratosphere (UTLS) is important to both stratospheric chemistry (as a source of OH) and to the climate system (as a potent greenhouse gas). Since 2004 the Microwave Limb Sounder instrument (MLS), on the Aura satellite platform, has made over 250,000 soundings of vertically resolved water vapor targeting the lower stratosphere over the Continental United States (CONUS). Many MLS measurements in UTLS made during the mid-summer season show abrupt enhancements of water vapor above the noise associated with the seasonally varying background. It has been suggested that these water vapor enhancements may be due to stratospheric injection of water by tropopause overshooting convective events. Until now these contributions have only been studied at the case study scale. We use the TRAJ3D model to compute Lagrangian back trajectories initialized at high density from within MLS footprints in the UTLS that have high water vapor enhancements. We then cross-reference those back trajectories with data products of tropopause overshooting convective events (Gridrad and GOES). This allows us to show the statistical relationship between tropopause overshooting convective events and stratospheric water vapor enhancement as observed by MLS throughout the long term dataset. We are also able to show the relative contribution of different regions with active deep convection to the total convective influence on UTLS airmasses with enhanced water vapor. We show how those regional contributions differ across CONUS and how they evolve seasonally.
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