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1 ENTRAINMENT and MICROPHYSICS in RICO Cu Hermann Gerber NASA/GISS Workshop Sept. 2006
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2 Scorer, R.S., and F.H. Ludlam: 1953: Bubble theory of penetrative convection. Q.J. Roy. Meteor. Soc., 79, 317-341. Erosion (Detrainment) Entrainment Rising Toroidal Thermal (Blyth, A.M., et al., 1988: J. Atmos. Sci., 45, 3944-3964.) (Baker, B., A., 1992: J. Atmos. Sci., 49, 387-404.) CLASSICAL ENTRAINMENT CONCEPT X (Damiani, et al, 2006: J. Atmos. Sci., 63, 1432-1450)
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3 MICROPHYSICS ISSUES 2. What about entrained CCN? 1. Homogenous or inhomogeneous mixing? 3. Entrainment scales? 4. Super-Adiabatic Drops?
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4 (Lasher-Trapp, S., W. Cooper, and A. Blyth, 2005: QJRMS, 195-220) SUPER ADIABATIC ADIABATIC PEAK HOMOGENOUS MIXINGINHOMOGENEOUS MIXING
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5 RICO FLIGHTS
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6 CONDITIONAL SAMPLING FOR ACTIVE TURRETS VERTICAL VELOCITY IS POSITIVE (~80%) IN AREA WITHLWC VERTICAL VELOCITY IS POSITIVE (~80%) IN AREA WITH LWC TOP OF CLOUD IS VISIBLE IN FORWARD-LOOKING VIDEO A SINGLE TURRET IS TRAVERSED CLOUD IS TRAVERSED NEAR CLOUD TOP (Raga, G.B., et al, 1990: J. Atmos. Sci., 47, 338-355.)
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8 (m)
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10 PVM FSSP Fast FSSP
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11 PVM
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12 10-cm RESOLUTION (1000 Hz) LWC DATA PVM
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13 (Gerber, H., et al, 2001: J. Atmos. Sci., 58, 497-503) (Burnet,F., and J.-L. Brenguier, 2006: J. Atmos. Sci., in print) (Schleuter, M.H., 2006: Master’s Thesis, U. of Utah) HOMOGENEOUS INHOMOGENEOUS EXTREME or (Brenguier, J.-L.,and F. Burnet, 1996: 12 th Int. Conf. Clouds and Precip; Zurich; 67-70)
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14 (Blyth A.M., and J. Latham, 1991: J.A.S., 48, 2367-2371) (Gerber, H., et al, 2000: 13 th Int.Conf. Clouds and Precip., Reno, NV, 105-108)
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16 COMPOSITE OF 35 Cu IN
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17 RICO, RF12 c z c e fractional entrain. scalar = q T c = cloud e =environment COMPOSITE FRACTIONAL ENTRAINMENT. 0062
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18 TKE (diss. rate) = [v’(rms)] 3 /L L = penetration length = 40m v’ = gust velocity COMPOSITE TKE DISSIPATION TKEINHOMOGENEOUS
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19 CLOUD EDGE (Brenguier, J.-L, 1993: J. Appl. Meteor., 32, 783-793) -60 -50 -40 -30 -20 -10 0 10 20 1000 Hz
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20 COMPOSITE OF ENTRAINED PARCEL LENGTH (Brenguier, J-L, and W.W. Grabowski, 1993: J. Atmos. Sci., 50, 120-136 ) (Kreuger, S.K., et al, 1997: J. Atmos. Sci., 54, 2697-2712)
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21 COMPOSITE OF ENTRAINED PARCEL PENETRATION
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22 ENTRAINMENT SHEATH NO HOLES SMALL PARCELS DILUTION DOMINATES RH HALO? NEW CCN ACTIVATION VORTEX RINGS? SUPER-ADIABATIC DROPS? ENTRAINMENT CONCEPT X
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23 TURRET SPECTRA
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24 THANK YOU hgerber6@comcast.net
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29 SPARE SLIDES FOLLOW
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32 Cu (Courtesy of Dr. Jim Hudson)
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33 Turb. (s) = (D 2 / TKE diss. ) 1/3 Drop (s) = 4r 2 / [4x10 -10 x (1-S)] RELAXATION TIME ANALYSIS D = entrained parcel width (m) r = droplet radius [10 --5 (m)] Drop (s ) Turb. (s ) Drop (s ) Turb. (s ) R = >> 1 << 1 INHOMOGENEOUS MIXING HOMOGENEOUS MIXING
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34 S.77.99 drop (s ) 5 100 D(m) 2 20 2 20 turb (s) 8.5 40 8.5 40 R.59.12 12 2.5 RELAXATION TIME RATIO, R CLOUD #21
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35 (Damiani, R., G. Vali, and S. Haimov, 2006: J.A.S., 1432-1450)
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