4,1- 1Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Mainz, Germany
- 2Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
- 3Air Pollution Control Division, Colorado Department of Public Health and Environment, Denver, USA
- 4Institute of Mathematics, Johannes Gutenberg University Mainz, Mainz, Germany
- 5Atmospheric Composition Observation and Modeling Laboratory, National Center for Atmospheric Research, Boulder, USA
Convective systems redistribute atmospheric trace gases due to the inherent high vertical wind velocities. Furthermore, the different convective cloud hydrometeors interact with soluble tracers, partially removing them from the atmosphere via precipitation. These processes have an impact on air quality, acid rain, and upper tropospheric composition and photochemistry via the outflow from the storms. Convection also affects the aerosol particle composition due to cloud processing and potentially enables the new particle formation in the upper troposphere, representing a feedback mechanism on the meteorology. Therefore, it is crucial to accurately represent convective transport and scavenging in models aiming to predict the chemical composition.
As current convection parameterising models struggle with this task, we developed a new parameterisation, Mainz Convective Transport and Scavenging (MCTS). MCTS calculates convective transport and scavenging quasi-simultaneously in one column. It considers tracer redistribution due to the high vertical wind velocity, uptake by droplets, and aqueous-phase chemistry. Retention and uptake by ice crystals are included as well.
To evaluate the novel scheme, a case study was performed for a convective situation observed during the NASA SEAC4RS campaign in the US in 2013. MCTS is compared to DC8 flight observations and to cloud-resolving WRF-Chem simulations performed by Cuchiara et al. (2020). MCTS performs reasonably and sufficiently reproduces the HCHO mixing ratios measured during the convective core intercept flights.
MCTS opens the path for a more consistent and accurate representation of convection composition interactions in large-scale models. Ensuring that the consequences of these interactions, i.e., new particle formation in the upper troposphere, radiative feedback, and air quality can be addressed with enhanced accuracy.
Reference
Cuchiara, G. C., Fried, A., Barth, M. C., Bela, M., Homeyer, C. R., Gaubert, B., et al. (2020). Vertical transport, entrainment, and scavenging processes affecting trace gases in a modeled and observed SEAC4RS case study. Journal of Geophysical Research: Atmospheres, 125, e2019JD031957. https://doi.org/10.1029/2019JD031957
How to cite: Jeske, A., Menken, J. M., Cuchiara, G. C., Ranocha, H., Barth, M. C., and Tost, H.: Mainz Convective Transport and Scavenging: A new parameterization of convection-chemistry-interaction in global chemistry-circulation models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1984, https://doi.org/10.5194/egusphere-egu26-1984, 2026.
