Martin Köhler, DWD - Meteo
Transcript of Martin Köhler, DWD - Meteo
cloud cover parameterisationMartin Köhler, DWD
ICON cloud communityMaike Ahlgrimm, Uli Blahak, Daniel Klocke, Alberto de Lozar, Ekaterina Machulskaya,
Matthias Raschendorfer, Sophia Schäfer, Axel Seifert
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ICON-atmo solar bias ICON-coupled SST bias
SST bias vs ERA5 TOA net solar bias vs CERES
ICON NWP 40km12 months 2019
Sophia Schäfer, Martin Köhler
ICON-seamless 160km12th month 1979(1st prototype)
Stephan Lorenz, Martin Köhler, Rene Redler
Clouds in ICON
• dynamics: 1/0• microphysics: 1/0• convection: small cloud updraft• turbulence: Gaussian distribution for buoyancy flux• radiation: diagnostic cloud cover
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diagnostic ICON cloud cover
k
k+1/2
k-1/2
Du ql,up
liquidvapor
qsat
∆q ∆q
qtopqbot
p
¶CC¶t
= (1-CC)Du
r-CCt decay
Tuning Parameters
tune_box_liq box width liquid cloudtune_box_liq_asy asymmetry liquid cloudtune_thicklayfac in-box overlapicpl_turb_clc turb. coupling to cloudlcalib_clcov post-calibration of TCC,…
… and more …
turbulent cloud convective cloud
EUREC4a 1.3.2020 NASA Worldview
TERRA VIIRSAQUA
equator overpass:10:30am
equator overpass:1:00pm
equator overpass:1:30pm
EUREC4a 7.2.2020 NASA Worldview
TERRA VIIRSAQUA
equator overpass:10:30am
equator overpass:1:00pm
equator overpass:1:30pm
EUREC4a 7.2.2020 NASA Worldview
TERRA VIIRSICON
equator overpass:10:30am
equator overpass:1:00pm12:00am (36h forecast)
ICON at 1.25km1º ⎼ 23º North-66º ⎼ -44ºEast
EUREC4a 1.25km ICONsimulations: Daniel Klocke
specific humidity
wTKE
liquid water cloud cover θv
simulation• 1.25km resolution• 36h forecast• 7.2.2020 12UTC• mean over ocean only• no convective parameterisation• TKE parameterisation• fractional cloud cover• graupel 1-moment microphysics
total water (qv+qc) PDF
3000m
4000m
2000m
1500m
1000m
Adrian Tompkins, 2002
beta distribution G:
beta function B:
PDF (cloud cover, total water) height
Box Width 20km
4000m
1500m
3000m 2000m
1000m
PDF (cloud cover, total water) resolution
Box Width 10km Box Width 20km Box Width 40km Box Width 80km
dw/dz
Box Width 20km
4000m
1500m
3000m 2000m
1000m
TKE
Box Width 20km
4000m
1500m
3000m 2000m
1000m
diagnostic ICON cloud cover
k
k+1/2
k-1/2
Du ql,upliquidvapor
qsat
qq qtopqbot
p
Beta distributionTompkins JAS (2002)
mean: dynamicsstandard deviation: TKE scheme
skewness: convection
goals:• combined cloud with turbulent and
convective source terms• diagnostic, simplified• resolution dependant• with and without convection
parameterisation
Extra Slides
EUREC4a 1.3.2020 NASA Worldview
TERRA VIIRSICON 1.25km
equator overpass:10:30am
equator overpass:1:00pm
snapshot:12:00am (36h forecast)
PDF (cloud cover, total water) height
Box Width 40km
theta,v
Box Width 20km
4000m
1500m
3000m 2000m
1000m
w
Box Width 20km
4000m
1500m
3000m 2000m
1000m
W,local – W,mean20km