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Investigating Entrainment and Microphysics in RICO Cu: Insights from NASA/GISS Workshop

This document summarizes discussions from the September 2006 NASA/GISS workshop focused on entrainment and microphysics in cloud dynamics, specifically related to RICO Cu. Key topics include classical entrainment concepts, erosion and detrainment processes, and various microphysics issues such as homogeneous versus inhomogeneous mixing. It highlights contributions from prominent researchers and provides a detailed analysis of data from RICO flights, emphasizing the importance of entrainment scales, cloud condensation nuclei (CCN), and turbulence effects on microphysical processes.

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Investigating Entrainment and Microphysics in RICO Cu: Insights from NASA/GISS Workshop

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  1. ENTRAINMENT and MICROPHYSICS in RICO Cu Hermann Gerber NASA/GISS Workshop Sept. 2006

  2. CLASSICAL ENTRAINMENT CONCEPT Erosion (Detrainment) Rising Toroidal Thermal Entrainment X Scorer, R.S., and F.H. Ludlam: 1953: Bubble theory of penetrative convection. Q.J. Roy. Meteor. Soc., 79, 317-341. (Blyth, A.M., et al., 1988: J. Atmos. Sci., 45, 3944-3964.) (Baker, B., A., 1992: J. Atmos. Sci., 49, 387-404.) (Damiani, et al, 2006: J. Atmos. Sci., 63, 1432-1450)

  3. MICROPHYSICS ISSUES 1. Homogenous or inhomogeneous mixing? 2. What about entrained CCN? 4.Super-AdiabaticDrops? 3. Entrainment scales?

  4. HOMOGENOUS MIXING INHOMOGENEOUS MIXING ADIABATIC PEAK SUPER ADIABATIC (Lasher-Trapp, S., W. Cooper, and A. Blyth, 2005: QJRMS, 195-220)

  5. RICO FLIGHTS

  6. CONDITIONAL SAMPLING FOR ACTIVE TURRETS VERTICAL VELOCITY IS POSITIVE (~80%) IN AREA WITHLWC TOP OF CLOUD IS VISIBLE IN FORWARD-LOOKING VIDEO CLOUD IS TRAVERSED NEAR CLOUD TOP A SINGLE TURRET IS TRAVERSED (Raga, G.B., et al, 1990: J. Atmos. Sci., 47, 338-355.)

  7. (m)

  8. PVM FSSP Fast FSSP

  9. PVM

  10. 10-cm RESOLUTION (1000 Hz) LWC DATA PVM

  11. INHOMOGENEOUS EXTREME HOMOGENEOUS c or (Brenguier, J.-L.,and F. Burnet, 1996: 12th Int. Conf. Clouds and Precip; Zurich; 67-70) (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)

  12. (Blyth A.M., and J. Latham, 1991: J.A.S., 48, 2367-2371) (Gerber, H., et al, 2000: 13th Int.Conf. Clouds and Precip., Reno, NV, 105-108)

  13. COMPOSITE OF 35 Cu IN

  14. COMPOSITE FRACTIONAL ENTRAINMENT RICO, RF12 .0062 djc /dz = -e (jc- je) e = fractional entrain. j = scalar = qT e =environment c = cloud

  15. COMPOSITE TKE DISSIPATION TKE (diss. rate) = [v’(rms)]3/L v’ = gust velocity L = penetration length = 40m TKE INHOMOGENEOUS

  16. CLOUD EDGE 1000 Hz -60 -50 -40 -30 -20 -10 0 10 20 (Brenguier, J.-L, 1993: J. Appl. Meteor., 32, 783-793)

  17. 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)

  18. COMPOSITE OF ENTRAINED PARCEL PENETRATION

  19. ENTRAINMENT CONCEPT ENTRAINMENT SHEATH DILUTION DOMINATES RH HALO? VORTEX RINGS? NO HOLES SMALL PARCELS X SUPER-ADIABATIC DROPS? NEW CCN ACTIVATION

  20. TURRET SPECTRA

  21. THANK YOU hgerber6@comcast.net

  22. SPARE SLIDES FOLLOW

  23. Cu (Courtesy of Dr. Jim Hudson)

  24. RELAXATION TIME ANALYSIS tDrop(s)= 4r2 / [4x10-10 x (1-S)] tTurb.(s) = (D2 / TKEdiss.)1/3 D = entrained parcel width (m) r = droplet radius [10--5 (m)] tDrop(s) >> 1 R = HOMOGENEOUS MIXING tTurb.(s) tDrop(s) << 1 R = INHOMOGENEOUS MIXING tTurb.(s)

  25. RELAXATION TIME RATIO, R CLOUD #21 S .77 .99 tdrop(s) 5 100 D(m) 2 20 2 20 tturb(s) 8.5 40 8.5 40 R .59 .1212 2.5

  26. (Damiani, R., G. Vali, and S. Haimov, 2006: J.A.S., 1432-1450)

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