PBL transports and clouds 32007 Martin Khler 1

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ECMWF PBL cloud parameterization futureMartin
Köhler, ECMWF

• Sept2006 ice supersaturation, implicit
  cumulus numerics
• June2007 radiation McICA, RRTM SW (14 bands)
• Fall2007 cumulus entrainment, PBL
  stratocumulus upgrades
• Spring2008 EDMF shallow convection DualM
• EDMF momentum transport
• exact parcel solution

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coupled ECMWF-ERA40 Surface temperature years
3-4 of integration
Antje Weisheimer ENSEMBLES
CY31R1 Sept 2006
CY32R1 June 2007
CY32R3 Fall 2007
model cycle impl. date
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Integral appraoch to PBL transports EDMF
operational
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EDMF two box M/K decomposition(Siebesma and
Cuijpers, 1995)
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Shallow ConvectionRoel Neggers, Martin Köhler,
Anton Beljaars
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• II. A proposed set of modifications
• Enables EDMF to also represent shallow cumulus
• (replacing the current shallow cumulus
  scheme)
• increased number of resolved updrafts
• flexible area partitioning of the updraft
  ensemble
• -gt determined by moist convective
  inhibition
• Allows gradual transitions to and from
  shallow cumulus
• flexible updraft entrainment
• The same entraining plume model is applied
  to all model updrafts
• flexible vertical structure of cumulus mass
  flux
• Dependent on inversion stability a bulk
  Kain Fritsch (1990) scheme
• -gt to reproduce cloud layers with
  varying degrees of conditional instability
• top-entrainment efficiency closure at shallow
  cumulus inversion
• Wyant et al. (JAS, 1997)
• a bimodal statistical cloud scheme within the
  PBL

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So does it work better?

• Step 1 Revisit as many prototype LES/CRM cases
  as possible

ql
qsat
qt
This should be a routine step in model development
Cloud fraction
Condensate
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Shallow ConvectionRoel Neggers , Martin Köhler,
Anton Beljaars
moist
dry
K
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EDMF PBL analytical updraft(with Peter Janssen)

• Parcel dominates PBL height (wu0) and updraft
  properties (?u, qu, uu).
• PBL height dominates mixing.
• Parcel is dominated by entrainment.
• Entrainment rule gives
  infinite entrainment at surface and PBL top.

Rescale
Updraft equations
Then
Solution
PBL height
Assume
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EDMF PBL analytical updraft(with Peter Janssen)
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Diffusion outside convective PBL
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MJO Tropical Velocity Potential
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MJO Power Symmetrical Tropical OLRA
CY32R3
NOAA obs
CY31R1
CY32R1
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Precipitation (DJF 1990-2005)
GPCP obs
CY32R3 - obs
CY32R1 - obs
CY31R1 - obs
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Cloud cover against ISCCP D2
ISCCP obs
CY32R3 - obs
CY31R1 - obs
CY32R1 - obs