Evaluation of the parametrized transport of lead-210 in high-altitude European sites

Abstract. One important aspect in current climate modelling is to correctly simulate the regional variability of aerosols forcings. A first step to address this issue is to evaluate the tropospheric vertical distribution of submicronic aerosol (including sulfate and organic aerosol) in particular in the free troposphere.

²¹⁰Pb is particularly interesting to study the dynamic transport by chemistry and transport models, because it is an excellent passive tracer of atmospheric circulation. Hence, it is a simple representative of atmospheric submicronic aerosol and its transport is well correlated with sulfate aerosol. Indeed, ²¹⁰Pb and ²²²Rn (its radioactive parent) have been widely used for model verification. We present here pluriannual simulations of ²¹⁰Pb made with the multiscale global to regional model MOCAGE of Météo-France, which allows to investigate resolution effects over Europe and specially anomalies in link with the heat wave episode of summer 2003 and associated increased convection.

Precisely, simulations over Europe over 3 years, 2002 to 2004, are compared with the original dataset gathered in particular over high-altitude sites during the CARBOSOL project. We particularly focus our attention on the vertical unresolved-scale transport parameterisation and analyse the strong seasonality in ²¹⁰Pb concentrations (maximum in summer, minimum in winter), which was exceptionnally marked in 2003.