idealized wintertime cloud simulations as performed by meso-nh
DESCRIPTION
Idealized wintertime cloud simulations as performed by Meso-NH. J.-P. Chaboureau and J.-P. Pinty Laboratoire d’Aérologie, Toulouse. IMPROVE orographic precipitation (CASE3) Cold air outbreak over the Japan Sea (CASE4). 2 bulk microphysical schemes. - PowerPoint PPT PresentationTRANSCRIPT
Idealized wintertime cloud simulations as performed
by Meso-NH
J.-P. Chaboureau and J.-P. PintyLaboratoire d’Aérologie, Toulouse
1. IMPROVE orographic precipitation (CASE3)
2. Cold air outbreak over the Japan Sea (CASE4)
2 bulk microphysical schemes
5 species: cloud, rain, ice, snow, graupel• 1-moment (Pinty and Jabouille 1998)
– Prognostic {rc} + {rr} + {ri} + {rs} + {rg}
– Diagnostic {Nc} + {Nr} + {Ni} + {Ns} + {Ng}
• 2-moment (Pinty 2002)
– Prognostic {rc, Nc} + {rr, Nr} + CCNact (Cohard and Pinty 2000)
{ri, Ni} + {rs} + {rg} + INnuc
– Diagnostic {Ns} + {Ng} with Ns/g=Cxas deduced from Field (1999) and
others
IMPROVE set-up• 2D domain
– 1-km mesh with 360 points (instead of 344)– 50 levels from 20 m (bottom) to 750 m (9-16 km)
• Open boundaries/6-h run• Initialization with RS (ice/snow set to 0)
Rela
tive
Hu
mid
ity
00
10 10 kmkm
Vertical X-sections after 4-h runMNH 1-m
clou
d
MNH 2-m
w +
tem
p
MM5
00
10 10 kmkm
Accumulated Precipitation
Domain-maximum mixing ratio time series
MM5 MNH 1-m MNH 2-m
00 6 h6 h 6 h6 h6 h6 h00 00cloud ice
cloud water
snowrairai
nn graupel
11
00
3030
344 km344 km 344 km344 km 344 km344 km
Japan Sea cloud set-up• 2D domain
– 2-km mesh with 512 points– 50 levels from 50 m (bottom) to 500 m (top)
• 24-h run / SST forcing• Initialization with Japan Sea sounding
(00 UTC 29 Jan 1993)
SST273 K
283 K
268 K
0 m
600 m
Vertical X-sections after 24-h runRel Hum %ice
MN
H 2
-mM
NH
1-m
Surface flux (H, LE) w and
0 km0 km-60 W/m2
4 km4 km240 W/m2
2 km2 km
200200 00
Vertical X-sections after 24-h runGraupel
MN
H 2
-mM
NH
1-m
Cloud water/ice Snow
Cloud top varying from 1.8 km to 2.5 km (close to the coast)
4 km4 km
2 km2 km
0 km0 km
Ice conc/mix ratio
Domain-maximum mixing ratio time series
MNH 1-m MNH 2-m
0024 h24 h 24 h24 h
1 g/kg1 g/kg
2-moment scheme: less cloud water and ice more snow
00
Conclusion
• 1-moment cloud scheme– Standard results
• 2-moment cloud scheme– More degree of freedom– Need further tests