University of Cambridge > Talks.cam > Centre for Atmospheric Science seminars, Chemistry Dept. > Global modelling of lightning and its impact on tropospheric ozone chemistry

Global modelling of lightning and its impact on tropospheric ozone chemistry

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If you have a question about this talk, please contact Dr Amanda Maycock.

Lightning is estimated to produce around 10% of global annual NOx emissions. While not the largest NOx source, lightning has particular importance because it emits directly into the free troposphere instead of at the surface. As a result, it is a key control on ozone production in the tropical upper troposphere. As a natural emissions source, lightning also has the potential to vary with climate change if its meteorological drivers are affected.

The parametrisation of lightning in most climate-chemistry models uses cloud top height as a proxy. This approach is known to contain large errors but there are few robust alternatives. I will present the development of an alternative parametrisation using upward ice flux which is more closely linked to thunderstorm charging theory. Comparisons are made between our ice flux-based parametrisation and existing parametrisations. The upward ice flux approach is then implemented in the climate-chemistry model, UKCA . UKCA is used to explore the differences in tropospheric ozone chemistry between the cloud top height approach versus the upward ice flux approach.

This talk is part of the Centre for Atmospheric Science seminars, Chemistry Dept. series.

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