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A two-moment microphysical scheme for mesoscale and microscale cloud resolving models

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A two-moment microphysical scheme for mesoscale and microscale cloud resolving models Axel Seifert National Center for Atmospheric Research Motivation WRF simulation ... – PowerPoint PPT presentation

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Date added: 31 October 2019
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Title: A two-moment microphysical scheme for mesoscale and microscale cloud resolving models


1
A two-moment microphysical scheme for mesoscale
and microscale cloud resolving models
Axel Seifert National Center for Atmospheric
Research
2
Motivation
  • Aerosol-Cloud interactions can be a strong
    feedback in the climate system
  • Quantitative precipitation forecasts suffer from
    oversimplified microphysical models
  • Many ongoing projects on weather
    modification, but little scientific knowledge
  • ? improved microphysical models are necessary

3
Microphysical models
x particle mass
4
Generalized Gamma Distribution
x particle mass, ? shape parameter, ?
tail parameter
D in ?m
D in ?m
5
A two-moment warm phase scheme
Use mass and number concentrations to get an
explicit size information ? 4 Variables
(Seifert and Beheng 2001, Atmos. Res.)
6
A two-moment mixed-phase cloud scheme
7
A two-moment mixed-phase cloud scheme
8
What happend so far ....
  • Comparison with bin microphysics
  • Sensitivity study showed that especially high
    CAPE, low wind shear convective systems are
    sensitive to aerosols/CCN
  • Simulation of isolated observed thunderstorms
  • Severe storms during BAMEX
  • WRF, MM5 and LM implementation

9
Comparison within HUCM
10
Comparison within HUCM
11
Timeseries of maximum mass concentrations
BIN BULK
CONT MARI
12
Total grid averaged precipitation
13
CCN effects on different storm types
Weisman and Klemp (1982) sensitivity study, but
now including CCN as a third external
parameter Variation of 1. CAPE 2. vertical
wind shear 3. CCN concentration Effects on total
precipitation?
(Seifert and Beheng 2003, submitted)
14
Total 3h-precipitation
multicell conv.
supercell convection
15
Total 3h-precipitation and rel. change for cont.
CCN
16
WRF simulation of a CRYSTAL-FACE storm
(100x80 km, 250 m resolution, warm bubble, single
sounding)
17
Observations vs. WRF simulation X-band
reflectivity
18
Observations vs. WRF simulation W-band
reflectivity
19
Attenuation by liquid water
20
Real-time WRF 4 km BAMEX Forecast
Valid 6/10/03 12Z
Composite NEXRAD Radar
4 km BAMEX forecast 36 h Reflectivity
4 km BAMEX forecast 12 h Reflectivity
21
BAMEX 10 June 00 UTC 09h
Column max. reflectivity (WRF)
WRFs Lin-type scheme
Reisner-Thompson scheme
Seifert-Beheng scheme
22
BAMEX 10 June 00 UTC 23h
Column max. reflectivity (WRF)
WRFs Lin-type scheme
Reisner-Thompson scheme
Seifert-Beheng scheme
23
BAMEX 10 June 00 UTC 23h
Accumulated precip during 23 h
WRFs Lin-type scheme
Reisner-Thompson scheme
Seifert-Beheng scheme
24
Acknowledgements Klaus D. Beheng, Karlsruhe Uli
Blahak, Karlsruhe Michael Baldauf,
Karlsruhe Jochen Förstner, Karlsruhe Alexander
Khain, Jerusalem Andrei Pokrovsky, Jerusalem Bill
Hall, NCAR Andy Heymsfield, NCAR Morris Weisman,
NCAR Gerry Heymsfield, NASA Scientific Computing
Centers at Karlsruhe and NCAR
25
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26
(No Transcript)
27
Various one- and two-moment schemes
28
BAMEX 10 June 00 UTC 19h
Column max. reflectivity (WRF)
WRFs Lin-type scheme
Reisner-Thompson scheme
Seifert-Beheng scheme
29
Maximum vertical velocities (HUCM)
30
Coupling of microphysics and dynamics!
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