Quantifying Tropopause-Overshooting Volume From Satellite and Radar Observations During the DCOTSS 2021 and 2022 Campaigns

This study quantifies the air volume injected into the stratosphere by overshooting convection detected by GOES-16/17 geostationary infrared imagery and NOAA NEXRAD precipitation echo top during the 2021 and 2022 Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) missions. This analysis addresses a key DCOTSS science question, namely “How much tropospheric air and water is irreversibly injected into the stratosphere by convection?” A novel method for defining individual storms or a cluster of adjacent storms as objects and tracking them throughout their lifetime facilitates the analysis. Overshooting convection injected 3.92 × 10⁶ – 5.36 × 10⁶ km³ of air into the stratosphere in 2021 and 9.59 × 10⁶ – 1.06 × 10⁷ km³ in 2022 over the North American study domain with GOES being higher than GridRad during both years. GOES overshooting detections were more uncertain due to difficulty differentiating updrafts from adjacent broad areas of cold outflow. Overshooting volume from the top 10 storm objects each year contributed 37%–52% of the total domain-wide volume. Total object-lifetime volume from these events ranged from ∼1.3 × 10⁵ to 7.9 × 10⁵ km³ for GOES and ∼8.7 × 10⁴ to 8.0 × 10⁵ km³ for GridRad. Overshooting seldom exceeded 5% of the total anvil area, and most often occupied <1%, demonstrating that very small regions within convection are responsible for impacting stratosphere composition. Despite differences in overshooting characteristics, airmasses initiated from GOES and NEXRAD overshooting and advected forward in time by reanalysis model winds had similar spatial and vertical distributions, indicating that geostationary satellite data could be used to study the long-range transport of overshooting airmasses.