Environmental Controls on Deep and Overshooting Convection Over the Contiguous U.S

• Published in: Journal of geophysical research. Atmospheres 2024-11, Vol.129 (22), p.n/a
• Main Authors: Bowman, Kenneth P., Rapp, Anita D.
• Format: Article
• Language: English
• Subjects: Air; Anticyclones; Atmosphere; Atmospheric chemistry; Atmospheric convection; CAPE; CIN; Climate; Climate and weather; Climate models; Climate prediction; Climatic analysis; Convection; Convective available potential energy; Convective storms; Environmental control; Environmental factors; Heavy rainfall; Ice particles; Lower atmosphere; Lower stratosphere; North American monsoon; Ozone; Ozone layer; Ozonosphere; Potential energy; Radar; Radar data; Rainfall; Severe weather; Storms; Stratosphere; Summer; Trace gases; tropopause; Troposphere; Updraft; Upper troposphere; Weather
• ISSN: 2169-897X; 2169-8996
• DOI: 10.1029/2024JD041841

During the summer season, deep convection over the central United States has a significant impact on the dynamics and composition of the upper troposphere and lower stratosphere (UTLS). These storms transport tropospheric air containing trace gases, ice particles, and aerosols into the UTLS, which can affect chemical and radiative processes over a large region. Because overshooting storms necessarily have strong updrafts, there is a marked correlation between overshooting and the occurrence of severe weather at the surface. Heat released by these storms also helps to drive the North American Monsoon Anticyclone (NAMA) in the UTLS, which partially confines air injected into the stratosphere by overshooting storms. In support of the Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) project, this study is a climatological analysis of the environmental factors that affect the occurrence of deep and overshooting storms. Using hourly analyses of overshooting storms based on GridRad radar data and ERA5 reanalyzes, we focus on the roles of convective available potential energy (CAPE), convective inhibition (CIN), jet location, and other relevant dynamical and thermodynamic variables. The results show that northward intrusion of airmasses containing moist high CAPE air from the Gulf of Mexico into the central plains plays a major role in producing the conditions necessary for overshooting storms with other factors playing secondary roles. Plain Language Summary Using observations of the atmosphere, this research shows that strong convective storms, which are most likely to produce heavy rain and severe weather, are regulated primarily by the amount of energy available to drive the storms and the energy needed to initiate convection. The strongest storms can also penetrate into the overlying stratosphere, which contains the Earth's protective ozone layer, carrying air from the lower atmosphere into the stratosphere. This is significant in part because climate models predict that the amount of energy available for convection will increase as the climate warms. As a result, the impact of strong convection on the atmosphere and on the stratosphere in particular may increase over coming decades. Key Points Overshooting convective storms have a global impact on the composition, chemistry, and radiative balance of the overlying stratosphere Deep and overshooting storms are strongly correlated with convective available potential energy (CAPE) and convective inhibi