Lightning and convection parameterisations – uncertainties in global modelling H. Tost, P. Jöckel, and J. Lelieveld Atmospheric Chemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, 55020 Mainz, Germany
Abstract. The simulation of convection, lightning and consequent NOx
emissions with global atmospheric chemistry models is associated with
large uncertainties since these processes are heavily parameterised.
Each parameterisation by itself has deficiencies and the combination of
these substantially increases the uncertainties compared to the
In this study several combinations of state-of-the-art convection and
lightning parameterisations are used in simulations with the
global atmospheric chemistry general circulation model ECHAM5/MESSy, and
are evaluated against lightning observations.
A wide range in the spatial and temporal variability of the simulated
flash densities is found, attributed to both types of parameterisations.
Some combinations perform well, whereas others are hardly applicable.
In addition to resolution dependent rescaling parameters, each
combination of lightning and convection schemes requires individual
scaling to reproduce the observed flash frequencies.
The resulting NOx profiles are inter-compared, however definite
conclusions about the most realistic profiles can currently not be
Citation: Tost, H., Jöckel, P., and Lelieveld, J.: Lightning and convection parameterisations – uncertainties in global modelling, Atmos. Chem. Phys., 7, 4553-4568, doi:10.5194/acp-7-4553-2007, 2007.