Emily Tinney - Nov 20

Name:     Emily Tinney

Title:    Convective Influence on United States Upper Troposphere Lower Stratosphere Composition

Location: NWC 5930

Date:     2019/11/20

Time:     03:00 PM

Series:   Weather and Climate Systems

Abstract: It has been well demonstrated that deep convective storms can alter the composition of the upper troposphere and lower stratosphere (UTLS). A comprehensive and quantitative understanding of this impact is vital to the prediction of climate and radiative forcing, yet it remains largely unknown. To help improve our understanding, this study matches high-resolution, hourly radar observations over the contiguous United States with downstream Aura Microwave Limb Sounder (MLS) trace gas profiles via a trajectory model over a 12-year period (2005-2016) to study how UTLS composition is impacted by convection. In particular, MLS trace gas and temperature profiles are classified as convectively influenced or not convectively influenced, and are analyzed and compared in tropopause-relative altitude to diagnose changes in UTLS composition from convection. Analyzed trace constituents include water vapor (H2O), ozone (O3), carbon monoxide (CO).

Consistent with previous studies, preliminary results indicate that convection leads to an increase in UTLS H2O and a decrease in O3. When composition is examined based on environment (tropical or extratropical), larger changes in composition are found within tropical environments. Increases in tropospheric pollutants can also be seen in convectively influenced profiles, which is again consistent with previous work. Sensitivities in convective influence to environmental characteristics, season, and location will also be discussed.