Numerical simulations of microphysical processes in pyro-convective clouds [Elektronische Ressource] / Philipp Reutter

Numerical simulations ofmicrophysical processes inpyro-convective cloudsDissertationzur Erlangung des Grades”Doktor der Naturwissenschaften”am Fachbereich Physikder Johannes Gutenberg-Universit¨atin MainzPhilipp Reuttergeboren inStuttgartiiTag der mundlic¨ hen Prufung:¨ Freitag, 13. November 2009iiiivAbstractDeep convection induced by vegetation fires is one of the most intense forms of at-mospheric convection. The extreme cloud dynamics with high updraft velocities (up−1to 20ms ) already at the cloud base, high water vapor supersaturations (up to 1%),and high number concentrations of aerosol particles freshly emitted by the fire (up to5 −31·10 cm ) represent a particular setting for aerosol-cloud interactions.A crucial step in the microphysical evolution of a convective cloud is the activationof aerosol particles to form cloud droplets. The activation process affects the initialnumber and size of cloud droplets, and can thus influence the evolution of the con-vective cloud and the formation of precipitation. The main parameters determiningthe initial number and size of cloud droplets are the number, size and hygroscopic-ity of aerosol particles available at the cloud base as well as the updraft velocity.