ccn effects on numerically simulated mixed-phase convective storms
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
CCN effects on numerically simulated mixed-phase
convective storms
with
Klaus D. Beheng, University Karlsruhe, Germany
Alexander Khain, Hebrew University Jerusalem, Israel
Axel Seifert
National Center for Atmospheric Research (ASP/MMM)
Motivation
• Explicit simulation of aerosol-cloud interactionis necessary to estimate indirect aerosol effects on climate
• Considering aerosol conditions might increasethe forecast skill of NWP models
• How can we improve the representation of clouds in weather and climate models?
(Seifert and Beheng 2001)
A two-moment 5-class cloud scheme
Nucleation? RICO!
(Seifert and Beheng 2003, submitted)
Comparison within theHebrew Univ. Cloud Model (HUCM)
Comparison within theHebrew Univ. Cloud Model (HUCM)
BIN BULK
CONT
MARI
Timeseries of maximum mass concentrations
Maximum vertical velocities
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
supercell convection
multicell conv.
Total 3h-precipitationand rel. change for cont. CCN
Coupling of microphysics and dynamics!
Continuous transition from maritime to cont. CCN
Confronting the model with real data!
Dual-wavelength radar data from CRYSTAL-FACE:
(data provided by G. Heymsfield, NASA)
Observations vs. WRF Simulation
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 spectralbin microphysics in the Hebrew Univ. Cloud Model
• A sensitivity study shows an inverse aerosol effectfor multicellular convection (latent heat effect)
• Validation with dual-wavelength radar?
Autoconversion
GATE squall line – total precip.
Bulk nucleation scheme