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JAMES C. BARNES

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William K. Widger Jr. and James C. Barnes

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Gary M. Barnes, James C. Fankhauser, and Wesley D. Browning

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The evolution of the vertical mass flux in isolated cumulus and cumulus congestus clouds is documented using two King Airs during the Convection and Precipitation/Electrification Experiment (CaPE,), conducted in east-central Florida during the summer of 1991. These clouds develop over the sea-breeze convergence in an environment characterized by low shear and moderate convective available potential energy. The aircraft, separated vertically by 600–1000 m, commence flying near-simultaneous penetrations as the cloud top passes through the altitude of the upper aircraft and continue sampling until the cloud disappears. The net vertical mass flux for each level is estimated; the difference in the mass flux between the two levels leads to a diagnosis of the net entrainment or detrainment that occurs laterally in the intervening cloud layer. This kinematic technique relies on determination of cloud edge based on liquid water measurements, a cloud shape factor, and the vertical velocity. The technique is not limited to the period prior to precipitation fall out like most conserved variable techniques nor does it require accurate measurement of in-cloud total water and temperature.

Results from 12 isolated clouds with radii of 0.5–1.5 km and lifetimes less than 25 min demonstrate that the vertical mass flux evolves in a well-behaved manner with clear growth and decay phases. Significant net lateral entrainment or detrainment is diagnosed, which complements the top entrainment that has been inferred from conserved thermodynamic variable techniques. Net entrainment dominates the growth stage, whereas net detrainment is most often seen during the decay stage of the cloud. An approximate entrainment rate averaged over cloud life is 1 km−1. The continuous nature of the updrafts demonstrates that these small clouds are best described as a single shedding thermal, not a series of bubbles ascending in the wake of each preceding bubble.

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Arnold H. Glaser, James C. Barnes, and Donald W. Beran

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A Monte Carlo technique simulates the effects of cloudcover on the performance of the Apollo On-board Navigation System. For each of three simulated Apollo missions, the probability of sighting at least a specific number of landmarks within the first two and one-half revolutions is determined. Cloudcover over the landmarks is derived from meteorological satellite data. These cloud amounts were found to be generally less than ground observed; the difference is believed to be due to the existence of small cumulus cells not resolved by the satellite, and the overestimation of sky cover by ground observers. A discussion of these factors is included.

The results of the mission simulation program indicate that the number of sightings can be materially increased by a choice of landmarks that are distributed to conform to the operational characteristics of the On-board Navigation System as much as by choice for optimum climate.

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Margaret A. LeMone, Gary M. Barnes, James C. Fankhauser, and Lesley F. Tarleton

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Perturbation pressure fields are measured by aircraft around the cloud base updrafts of seven clouds ranging in size from weak cumulus congestus to intense cumulonimbus during CCOPE (1981). The fields are characterized by a high-low pressure couplet of similar size to the updraft, but a quarter-wavelength out of Phase, with the minimum pressure downshear of the updraft maximum. An estimate of the terms in the Poisson equation for pressure show that the pressure perturbation results chiefly from the interaction of the updraft with the vertical shear of the environmental horizontal wind. The behavior of the pressure oscillation is well predicted by inserting sinusoidal functions in the corresponding terms in the Poisson equation. The amplitude of the pressure oscillation is proportional to the wavelengths of the pressure and vertical-velocity fields, the amplitude of the vertical-velocity oscillation, and the vertical shear of the horizontal environmental wind through cloud base, measured in the direction of the maximum pressure gradient.

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M. Ades, R. Adler, Rob Allan, R. P. Allan, J. Anderson, Anthony Argüez, C. Arosio, J. A. Augustine, C. Azorin-Molina, J. Barichivich, J. Barnes, H. E. Beck, Andreas Becker, Nicolas Bellouin, Angela Benedetti, David I. Berry, Stephen Blenkinsop, Olivier. Bock, Michael G. Bosilovich, Olivier. Boucher, S. A. Buehler, Laura. Carrea, Hanne H. Christiansen, F. Chouza, John R. Christy, E.-S. Chung, Melanie Coldewey-Egbers, Gil P. Compo, Owen R. Cooper, Curt Covey, A. Crotwell, Sean M. Davis, Elvira de Eyto, Richard A. M de Jeu, B.V. VanderSat, Curtis L. DeGasperi, Doug Degenstein, Larry Di Girolamo, Martin T. Dokulil, Markus G. Donat, Wouter A. Dorigo, Imke Durre, Geoff S. Dutton, G. Duveiller, James W. Elkins, Vitali E. Fioletov, Johannes Flemming, Michael J. Foster, Richard A. Frey, Stacey M. Frith, Lucien Froidevaux, J. Garforth, S. K. Gupta, Leopold Haimberger, Brad D. Hall, Ian Harris, Andrew K Heidinger, D. L. Hemming, Shu-peng (Ben) Ho, Daan Hubert, Dale F. Hurst, I. Hüser, Antje Inness, K. Isaksen, Viju John, Philip D. Jones, J. W. Kaiser, S. Kelly, S. Khaykin, R. Kidd, Hyungiun Kim, Z. Kipling, B. M. Kraemer, D. P. Kratz, R. S. La Fuente, Xin Lan, Kathleen O. Lantz, T. Leblanc, Bailing Li, Norman G Loeb, Craig S. Long, Diego Loyola, Wlodzimierz Marszelewski, B. Martens, Linda May, Michael Mayer, M. F. McCabe, Tim R. McVicar, Carl A. Mears, W. Paul Menzel, Christopher J. Merchant, Ben R. Miller, Diego G. Miralles, Stephen A. Montzka, Colin Morice, Jens Mühle, R. Myneni, Julien P. Nicolas, Jeannette Noetzli, Tim J. Osborn, T. Park, A. Pasik, Andrew M. Paterson, Mauri S. Pelto, S. Perkins-Kirkpatrick, G. Pétron, C. Phillips, Bernard Pinty, S. Po-Chedley, L. Polvani, W. Preimesberger, M. Pulkkanen, W. J. Randel, Samuel Rémy, L. Ricciardulli, A. D. Richardson, L. Rieger, David A. Robinson, Matthew Rodell, Karen H. Rosenlof, Chris Roth, A. Rozanov, James A. Rusak, O. Rusanovskaya, T. Rutishäuser, Ahira Sánchez-Lugo, P. Sawaengphokhai, T. Scanlon, Verena Schenzinger, S. Geoffey Schladow, R. W Schlegel, Eawag Schmid, Martin, H. B. Selkirk, S. Sharma, Lei Shi, S. V. Shimaraeva, E. A. Silow, Adrian J. Simmons, C. A. Smith, Sharon L Smith, B. J. Soden, Viktoria Sofieva, T. H. Sparks, Paul W. Stackhouse Jr., Wolfgang Steinbrecht, Dimitri A. Streletskiy, G. Taha, Hagen Telg, S. J. Thackeray, M. A. Timofeyev, Kleareti Tourpali, Mari R. Tye, Ronald J. van der A, Robin, VanderSat B.V. van der Schalie, Gerard van der SchrierW. Paul, Guido R. van der Werf, Piet Verburg, Jean-Paul Vernier, Holger Vömel, Russell S. Vose, Ray Wang, Shohei G. Watanabe, Mark Weber, Gesa A. Weyhenmeyer, David Wiese, Anne C. Wilber, Jeanette D. Wild, Takmeng Wong, R. Iestyn Woolway, Xungang Yin, Lin Zhao, Guanguo Zhao, Xinjia Zhou, Jerry R. Ziemke, and Markus Ziese
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