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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.
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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 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) 10 km Relative Humidity 0
Vertical X-sections after 4-h run MM5 MNH 1-m MNH 2-m 10 km w + temp 0 cloud
30 Accumulated Precipitation MNH 2-m MM5 MNH 1-m 0 344 km 344 km 344 km Domain-maximum mixing ratio time series 1 cloud water snow rain graupel cloud ice 6 h 0 6 h 0 6 h 0
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) 283 K SST 273 K 268 K 600 m 0 m
Vertical X-sections after 24-h run Surface flux(H, LE) w and Rel Hum %ice 240 W/m2 4 km 2 km MNH 1-m 0 km -60 W/m2 200 0 MNH 2-m
Vertical X-sections after 24-h run Snow Graupel Cloud water/ice 4 km MNH 1-m 2 km 0 km Ice conc/mix ratio MNH 2-m Cloud top varying from 1.8 km to 2.5 km (close to the coast)
Domain-maximum mixing ratio time series MNH 1-m MNH 2-m 1 g/kg 24 h 0 24 h 0 2-moment scheme: less cloud water and ice more snow
Conclusion • 1-moment cloud scheme • Standard results • 2-moment cloud scheme • More degree of freedom • Need further tests