The Observed Impact of the Lower Stratospheric Thermodynamic Environment on Overshooting Top Characteristics During the RELAMPAGO‐CACTI Field Campaign

Berman, M.T., R.J. Trapp, S.W. Nesbitt, and L. Di Girolamo (2024), The Observed Impact of the Lower Stratospheric Thermodynamic Environment on Overshooting Top Characteristics During the RELAMPAGO‐CACTI Field Campaign, J. Geophys. Res., 129, e2023JD040348, doi:10.1029/2023JD040348.
Abstract

Overshooting tops (OTs) are manifestations of deep convective updrafts that extend above the tropopause into the stratosphere. They can induce dynamic perturbations and result in irreversible transport of aerosols, water vapor and other mass from the troposphere into the stratosphere, thereby impacting the chemical composition and radiative processes of the stratosphere. These and other effects of OTs depend on their characteristics such as depth and area, which are understood to connect to mid‐tropospheric updraft speed and width, respectively. Less understood is how static stability in the lower stratosphere (LS) potentially modulates these OT–updraft connections, thus motivating the current study. Here, LS static stability and observed OT characteristics are quantified and compared using a combination of reanalysis data, observed rawinsonde data and geostationary satellite data. A weak to moderate relationship between OT depth and LS lapse rate and Brunt‐Väisälä frequency (N2) (R = 0.38, 0.37, respectively) is found, implying that OT depth is reduced with an increasingly stable LS. In contrast, a weak relationship (R = 0.03, 0.03, respectively) is found between OT area and LS static stability, implying that OT area is controlled primarily by mid to upper tropospheric updraft area. OT duration has a weak relationship to LS lapse rate and N2 (R = 0.02, 0.02, respectively). These relationships may be useful in interpreting mid‐ and low‐level storm dynamics from satellite‐observed characteristics of OTs in near real‐time. Plain Language Summary An overshooting top (OT) is a domed protrusion of a storm that reaches the stratosphere. These phenomena are important for their impact on stratospheric chemistry and their relationship to on‐the‐ground severe weather hazards. Spatial trends in OTs in southeastern South America are explored. Additionally, it is shown that static stability in the LS can be related to some aspects of OTs.

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Research Program
Atmospheric Dynamics and Precipitation Program (ADP)
Funding Sources
NASA FINNEST
NASA ROSES A.26

 

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