250 likes | 349 Views
CCN effects on numerically simulated mixed-phase convective storms. Axel Seifert National Center for Atmospheric Research (ASP/MMM). with Klaus D. Beheng, University Karlsruhe, Germany Alexander Khain, Hebrew University Jerusalem, Israel. Motivation.
E N D
CCN effects on numerically simulated mixed-phase convective storms Axel Seifert National Center for Atmospheric Research (ASP/MMM) with Klaus D. Beheng, University Karlsruhe, Germany Alexander Khain, Hebrew University Jerusalem, Israel
Motivation • Explicit simulation of aerosol-cloud interaction is necessary to estimate indirect aerosol effects on climate • Considering aerosol conditions might increase the forecast skill of NWP models • How can we improve the representation of clouds in weather and climate models?
A two-moment 5-class cloud scheme (Seifert and Beheng 2001)
Timeseries of maximum mass concentrations BIN BULK CONT MARI
Total grid averaged precipitation (Seifert et al. 2004, submitted)
A numerical study of CCN effects on different storm types • Weisman and Klemp (1982) • sensitivity study, but nowincluding CCN as a third external parameter: • Variation of • 1. CAPE 2. vertical wind shear3. CCN concentration • Effects on total precipitation? (Seifert and Beheng 2003, submitted)
Total 3h-precipitation multicell conv. supercell convection
Confronting the model with real data! Dual-wavelength radar data from CRYSTAL-FACE: (data provided by G. Heymsfield, NASA)
Summary • A new two-moment microphysical scheme has been developed and is implemented in WRF (KAMM2, LM, MM5) • The scheme is able to resolve CCN effects explicitly • The scheme shows a good agreement with the spectral bin microphysics in the Hebrew Univ. Cloud Model • A sensitivity study shows an inverse aerosol effect for multicellular convection (latent heat effect) • Validation with dual-wavelength radar?