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Freeman F. Hall Jr.

Abstract

Wind power spectral density measured in the lower and middle troposphere under zonal flow conditions is consistent with a −5/3 slope to frequencies as high as 10−2 Hz. By conversion of frequency to a spatial coordinate it is found that a satellite-borne lidar when averaging such winds over a 300 km grid scale would measure the synoptic-scale wind with a 98% representativeness index.

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Freeman F. Hall Jr.
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D. W. Beran and F. F. Hall Jr.

The application of ground-based remote-sensing systems for monitoring those meteorological parameters of importance in urban air pollution is discussed. Typical system considerations include an analysis of site characteristics and sensor location. Examples of how remote-sensing systems might be applied to air pollution meteorology are given.

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P. A. Mandics and F. F. Hall Jr.

An acoustic echo sounder mounted on the NOAA ship Oceanographer during GATE proved to be a valuable tool for investigating the structure and dynamics of the tropical marine boundary layer up to 800 m in height. Under suppressed weather conditions the facsimile-recorded echo intensity returns depicted a mixed layer characterized by convective plumes rising from the surface of the water to 400 m. Disturbed weather events resulted in a substantial modification of the boundary layer; layered structures formed that at times limited the depth of the mixed layer to 100 m. The Doppler frequency shift of the acoustic returns made it possible to determine the vertical velocity field.

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F. F. Hall Jr. and W. D. Neff

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F. F. Hall Jr., J. G. Edinger, and W. D. Neff

Abstract

The turbulent temperature structure and winds in thermal convective plumes over prairie grassland have been investigated with an acoustic echo sounder system. Three spaced acoustic antennas, with two inclined at 45° elevation, were used to provide plume shape information and Doppler-derived total wind-vector patterns between heights of 70 and 500 m. Supporting in situ measurements were made on a 15 m tower, with a tethered balloon-supported Boundary Layer Profiler, and from a light aircraft. The most probable orientation of the plumes was nearly vertical, but frequent upwind and downwind tilts were also observed. Maximum positive vertical velocities in the plumes at midday were near 2 m s−1, while maximum downward currents were one-half this value. Acoustic echoes from regions above the mixed layer, corresponding in height to an elevated temperature inversion, correlate well with regions of maximum wind shear.

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R. J. Wyckoff, D. W. Beran, and F. F. Hall Jr.

Abstract

Temperature profiles measured with a radiosonde are compared with returns from an acoustic echo sounder throughout the height range 50–700 m. In general, the sounder records indicate the temperature inversion to be somewhat lower than do the radiosonde records. Reasons for this apparent discrepancy and the advantage of the sounder, in being able to monitor continuously the inversion structure and undulations produced by wind shear, are discussed. It was proved feasible to operate the acoustic sounder in a noisy commercial district with little detrimental effect on the ability to detect atmospheric temperature structure. It is concluded from this preliminary investigation that the combination of the radiosonde and the acoustic echo sounder provides a much more valuable tool for monitoring structure in the stable planetary boundary layer than either device used alone.

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W. J. Gutowski Jr, P. A. Ullrich, A. Hall, L. R. Leung, T. A. O’Brien, C. M. Patricola, R. W. Arritt, M. S. Bukovsky, K. V. Calvin, Z. Feng, A. D. Jones, G. J. Kooperman, E. Monier, M. S. Pritchard, S. C. Pryor, Y. Qian, A. M. Rhoades, A. F. Roberts, K. Sakaguchi, N. Urban, and C. Zarzycki

ABSTRACT

Regional climate modeling addresses our need to understand and simulate climatic processes and phenomena unresolved in global models. This paper highlights examples of current approaches to and innovative uses of regional climate modeling that deepen understanding of the climate system. High-resolution models are generally more skillful in simulating extremes, such as heavy precipitation, strong winds, and severe storms. In addition, research has shown that fine-scale features such as mountains, coastlines, lakes, irrigation, land use, and urban heat islands can substantially influence a region’s climate and its response to changing forcings. Regional climate simulations explicitly simulating convection are now being performed, providing an opportunity to illuminate new physical behavior that previously was represented by parameterizations with large uncertainties. Regional and global models are both advancing toward higher resolution, as computational capacity increases. However, the resolution and ensemble size necessary to produce a sufficient statistical sample of these processes in global models has proven too costly for contemporary supercomputing systems. Regional climate models are thus indispensable tools that complement global models for understanding physical processes governing regional climate variability and change. The deeper understanding of regional climate processes also benefits stakeholders and policymakers who need physically robust, high-resolution climate information to guide societal responses to changing climate. Key scientific questions that will continue to require regional climate models, and opportunities are emerging for addressing those questions.

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W. J. Gutowski Jr., P. A. Ullrich, A. Hall, L. R. Leung, T. A. O’Brien, C. M. Patricola, R. W. Arritt, M. S. Bukovsky, K. V. Calvin, Z. Feng, A. D. Jones, G. J. Kooperman, E. Monier, M. S. Pritchard, S. C. Pryor, Y. Qian, A. M. Rhoades, A. F. Roberts, K. Sakaguchi, N. Urban, and C. Zarzycki
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Robert J. H. Dunn, F. Aldred, Nadine Gobron, John B. Miller, Kate M. Willett, M. Ades, Robert Adler, Richard, P. Allan, Rob Allan, J. Anderson, Anthony Argüez, C. Arosio, John A. Augustine, C. Azorin-Molina, J. Barichivich, H. E. Beck, Andreas Becker, Nicolas Bellouin, Angela Benedetti, David I. Berry, Stephen Blenkinsop, Olivier Bock, X. Bodin, Michael G. Bosilovich, Olivier Boucher, S. A. Buehler, B. Calmettes, Laura Carrea, Laura Castia, Hanne H. Christiansen, John R. Christy, E.-S. Chung, Melanie Coldewey-Egbers, Owen R. Cooper, Richard C. Cornes, Curt Covey, J.-F. Cretaux, M. Crotwell, Sean M. Davis, Richard A. M. de Jeu, Doug Degenstein, R. Delaloye, Larry Di Girolamo, Markus G. Donat, Wouter A. Dorigo, Imke Durre, Geoff S. Dutton, Gregory Duveiller, James W. Elkins, Vitali E. Fioletov, Johannes Flemming, Michael J. Foster, Stacey M. Frith, Lucien Froidevaux, J. Garforth, Matthew Gentry, S. K. Gupta, S. Hahn, Leopold Haimberger, Brad D. Hall, Ian Harris, D. L. Hemming, M. Hirschi, Shu-pen (Ben) Ho, F. Hrbacek, Daan Hubert, Dale F. Hurst, Antje Inness, K. Isaksen, Viju O. John, Philip D. Jones, Robert Junod, J. W. Kaiser, V. Kaufmann, A. Kellerer-Pirklbauer, Elizabeth C. Kent, R. Kidd, Hyungjun Kim, Z. Kipling, A. Koppa, B. M. Kraemer, D. P. Kratz, Xin Lan, Kathleen O. Lantz, D. Lavers, Norman G. Loeb, Diego Loyola, R. Madelon, Michael Mayer, M. F. McCabe, Tim R. McVicar, Carl A. Mears, Christopher J. Merchant, Diego G. Miralles, L. Moesinger, Stephen A. Montzka, Colin Morice, L. Mösinger, Jens Mühle, Julien P. Nicolas, Jeannette Noetzli, Ben Noll, J. O’Keefe, Tim J. Osborn, T. Park, A. J. Pasik, C. Pellet, Maury S. Pelto, S. E. Perkins-Kirkpatrick, G. Petron, Coda Phillips, S. Po-Chedley, L. Polvani, W. Preimesberger, D. G. Rains, W. J. Randel, Nick A. Rayner, Samuel Rémy, L. Ricciardulli, A. D. Richardson, David A. Robinson, Matthew Rodell, N. J. Rodríguez-Fernández, K.H. Rosenlof, C. Roth, A. Rozanov, T. Rutishäuser, Ahira Sánchez-Lugo, P. Sawaengphokhai, T. Scanlon, Verena Schenzinger, R. W. Schlegel, S. Sharma, Lei Shi, Adrian J. Simmons, Carolina Siso, Sharon L. Smith, B. J. Soden, Viktoria Sofieva, T. H. Sparks, Paul W. Stackhouse Jr., Wolfgang Steinbrecht, Martin Stengel, Dimitri A. Streletskiy, Sunny Sun-Mack, P. Tans, S. J. Thackeray, E. Thibert, D. Tokuda, Kleareti Tourpali, Mari R. Tye, Ronald van der A, Robin van der Schalie, Gerard van der Schrier, M. van der Vliet, Guido R. van der Werf, A. Vance, Jean-Paul Vernier, Isaac J. Vimont, Holger Vömel, Russell S. Vose, Ray Wang, Markus Weber, David Wiese, Anne C. Wilber, Jeanette D. Wild, Takmeng Wong, R. Iestyn Woolway, Xinjia Zhou, Xungang Yin, Guangyu Zhao, Lin Zhao, Jerry R. Ziemke, Markus Ziese, and R. M. Zotta
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