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2. Seasonal and Local Time Variation in the Observed Peak of the Meteor Altitude Distributions by Meteor Radars.

Author

Dawkins, E. C. M., Janches, D., Stober, G., Carrillo‐Sánchez, J. D., Lieberman, R. S., Jacobi, C., Moffat‐Griffin, T., Mitchell, N. J., Cobbett, N., Batista, P. P., Andrioli, V. F., Buriti, R. A., Murphy, D. J., Kero, J., Gulbrandsen, N., Tsutsumi, M., Kozlovsky, A., Lester, M., Kim, J.‐H., and Lee, C.

Subjects
GREENHOUSE gases, GRAVITY waves, SOLAR cycle, ATMOSPHERIC density, ATMOSPHERE, METEOROIDS, METEOR showers
Abstract

Meteoroids of sub‐milligram sizes burn up high in the Earth's atmosphere and cause streaks of plasma trails detectable by meteor radars. The altitude at which these trails, or meteors, form depends on a number of factors including atmospheric density and the astronomical source populations from which these meteoroids originate. A previous study has shown that the altitude of these meteors is affected by long‐term linear trends and the 11‐year solar cycle related to changes in our atmosphere. In this work, we examine how shorter diurnal and seasonal variations in the altitude distribution of meteors are dependent on the geographical location at which the measurements are performed. We use meteoroid altitude data from 18 independent meteor radar stations at a broad range of latitudes and investigate whether there are local time (LT) and seasonal variations in the altitude of the peak meteor height, defined as the majority detection altitude of all meteors within a certain period, which differ from those expected purely from the variation in the visibility of their astronomical source. We find a consistent LT and seasonal response for the Northern Hemisphere locations regardless of latitude. However, the Southern Hemisphere locations exhibit much greater LT and seasonal variation. In particular, we find a complex response in the four stations located within the Southern Andes region, which indicates that the strong dynamical atmospheric activity, such as the gravity waves prevalent here, disrupts, and masks the seasonality and dependence on the astronomical sources. Plain Language Summary: Small meteoroids burn up high in the Earth's atmosphere producing trails of plasma detectable by ground‐based meteor radar instruments. The altitude at which these trails occur depends on a number of factors including atmospheric density and the astronomical source populations from which these meteoroids originate. Previous work demonstrated that the altitude at which the majority of these meteoroids burn up (termed "peak meteor altitude") is affected by long‐term atmospheric changes, such as those related to greenhouse gas emissions and the 11‐year solar cycle. Here, we focus on shorter timescales and analyze meteoroid altitude data from 18 geographically diverse meteor radars to examine the local time (LT) and seasonal variation in the peak meteor altitudes on a latitude basis. We find a consistent LT and seasonal response among the six Northern Hemisphere meteor radar station locations irrespective of latitude. However, we find a more complex response among the 12 Southern Hemisphere stations with much greater LT and seasonal variation. In particular, we found a complex response in the four stations located within the Southern Andes region, a geographic region known for intense atmospheric gravity wave activity, which acts to mask and disrupt the seasonality and dependence on the astronomical sources. Key Points: Local time (LT) and seasonal variations in the peak meteor height exist, which differ from those expected from astronomical variation aloneThere is a consistent LT and seasonal response in the Northern Hemisphere locations regardless of latitudeA complex response in the Andes region where a strong gravity wave component acts to mask seasonality and dependence on astronomical sources [ABSTRACT FROM AUTHOR]

Published
2024
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4. Solar Cycle and Long‐Term Trends in the Observed Peak of the Meteor Altitude Distributions by Meteor Radars.

Author

Dawkins, E. C. M., Stober, G., Janches, D., Carrillo‐Sánchez, J. D., Lieberman, R. S., Jacobi, C., Moffat‐Griffin, T., Mitchell, N. J., Cobbett, N., Batista, P. P., Andrioli, V. F., Buriti, R. A., Murphy, D. J., Kero, J., Gulbrandsen, N., Tsutsumi, M., Kozlovsky, A., Kim, J. H., Lee, C., and Lester, M.

Subjects
SOLAR cycle, GREENHOUSE gases, THERMOSPHERE, METEORS, EFFECT of human beings on climate change, MIDDLE atmosphere, UPPER atmosphere
Abstract

The mesosphere/lower thermosphere (MLT, 80–100 km) region is an important boundary between Earth's atmosphere below and space above and may act as a sensitive indicator for anthropogenic climate change. Existing observational and modeling studies have shown the middle atmosphere and the MLT is cooling and contracting because of increasing greenhouse gas emissions. However, trend analyses are highly sensitive to the time periods covered, their length, and the measurement type and methodology used. We present for the first time the linear and 11‐year solar cycle responses in the meteor ablation altitude distributions observed by 12 meteor radars at different locations. Decreasing altitudes were seen at all latitudes (linear trends varying from −10.97 to −817.95 m dec−1), and a positive correlation with solar activity was seen for most locations. The divergence of responses at high latitudes indicates an important and complex interplay between atmospheric changes and dynamics at varying time scales. Plain Language Summary: High up in our atmosphere lies the mesosphere/lower thermosphere region (80–100 km); an important transition zone between the atmosphere below and space above. Existing studies indicate that this region is changing (cooling and contracting) in response to increasing greenhouse gas emissions, quite unlike the net warming we see near the surface. However these trend studies are often highly sensitive to choice and length of time period covered, and the methodology and type of measurements used. Here we present for the first time a self‐consistent methodology applied to 12 different meteor radar station datasets located at a diverse range of latitudes. We looked at changes in the mean peak altitude of individual meteoroid detections, and found decreasing peak altitudes at all locations examined (linear trends varying from −10.97 to −817.95 m decade−1) consistent with a global cooling and contracting of the upper atmosphere. We also examined the response to the 11‐year solar cycle and found a positive correlation with solar activity (i.e., increased meteoroid peak altitudes during solar maximum, and vice versa) for low and mid‐latitude locations. However we found an anti‐correlation at high latitudes suggestive of an important and complex interplay between atmospheric changes and dynamics at varying time scales. Key Points: Use of geographically diverse meteor radar peak detection altitudes to assess long‐term and 11‐year solar cycle (SC) trends in mesopause regionThe altitude of observed peak meteor height has decreased over time at all locations, regardless of latitude and data setPositive correlation at low‐ and mid‐latitude locations with the 11‐year SC, but more complex response at high‐latitudes [ABSTRACT FROM AUTHOR]

Published
2023
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10. A Conjugate Study of Mean Winds and Planetary Waves Employing Enhanced Meteor Radars at Rio Grande, Argentina (53.8degS) and Juliusruh, Germany (54.6degN)

Author

Fritts, D. C, Imura, H, Lieberman, R, Janches, D, and Singer, W

Subjects
Meteorology And Climatology
Abstract

Two meteor radars with enhanced power and sensitivity and located at closely conjugate latitudes (54.6degN and 53.8degS) are employed for inter-hemispheric comparisons of mean winds and planetary wave structures. Our study uses data from June 2008 through May 2010 during which both radars provided nearly continuous wind measurements from approx.80 to 100 km. Monthly mean winds at 53.8degS exhibit a somewhat stronger westward mean zonal jet in spring and early summer at lower altitudes and no westward monthly mean winds at higher altitudes. In contrast, westward mean winds of approx.5-10 m/s at 54.6degN extend to above 96 km during late winter and early spring each year. Equatorward monthly mean winds extend approximately from spring to fall equinox at both latitudes, with amplitudes of approx.5-10 m/s and more rapid decreases in amplitude at 54.6degN at higher altitudes. Meridional mean winds are more variable at both latitudes during fall and winter, with both poleward and equatorward monthly means indicating longer-period variability. Planetary waves seen in the 2-day mean data are episodic and variable at both sites, exhibit dominant periodicities of approx.8-10 and 16-20 days and are more confined to late fall and winter at 54.6degN. At both latitudes, planetary waves in the two period bands coincide closely in time and exhibit similar horizontal velocity covariances that are positive (negative) at 54.6degN (53.8degS) during peak planetary wave responses.

Published
2011

13. 93rd annual convention podium and poster abstracts

Author

Davis, C. M., Strong, S. A., Hellinger, M. D., Williamson, P. R., Larach, S. W., Ferrara, A., Blake, T. B., Medich, D. S., Ziv, Y., Oakley, J. R., Reissman, P., Piccirillo, M., Ulrich, A., Nogueras, J. J., Wexner, S. D., Rubin, M. S., Bodenstein, L. E., Kent, K. C., Williamson, M. E. R., Lewis, W. G., Sagar, P. M., Holdsworth, P. J., Johnston, D., Fazio, V. W., Goldblum, J. R., Sirimarco, M. T., Lavery, I. C., Petras, R. E., Treem, W. R., Cohen, J., Davis, P. M., Hyams, J. S., Eu, K. W., Bartolo, D. C. C., Green, J. D., Riether, R. D., Rosen, L., Stasik, J. J., Sheets, J. A., Reed, J., Khubchandani, I. T., Armitage, N. C., Chapman, M., Hardcastle, J. D., Viamonte, M., Plasencia, G., Wiltz, O., Jacobs, M., Finan, P. J., Passaro, M., Church, J. M., McGannon, E., Wilson, M., Hull-Boiner, S., Kollmorgen, C. F., Meagher, A. P., Wolff, B. G., Pemberton, J. H., Martenson, J. A., Ilstrup, D. M., Moran, M. R., Ramos, A., Rothenberger, D. A., Goldberg, S. M., Johnson, D., Madoff, R. D., Wong, W. D., Finne, III, C. O., Konishi, F., Furuta, K., Kanazawa, K., Lockhart, D., Schmitt, S., Caushaj, P. P., Garcia-Aguilar, J., Belmonte, C., Schiesel, E. C., Mazier, W. P., Senagore, A. J., Piccirillo, M. F., Teoh, T. -A., Yoon, K. -S., Paul, R. A. Patino, Lucas, J., Nelson, R., Norton, N., Cautley, E., Schouten, W. R., Briel, J. W., Auwerda, J. J. A., de Graaf, E. J. R., Lowry, A. C., Sentovich, S. M., Blatchford, G. J., Rivela, L. J., Thorson, A. G., Christensen, M. A., Jorge, J. M. N., Yang, Y. K., Shafik, A., Allendorf, J. D. F., Kayton, M. L., Libutti, S. K., Trokel, M. J., Whelan, R. L., Treat, M. R., Nowygrod, R., Bessler, M., Frank, R. E., Saclarides, T. J., Leurgans, S., Speziale, N. J., Drab, E., Rubin, D., Hull, T. L., Schroeder, T. K., Scholefield, J. H., Ogunbiyi, O. A., Smith, J. H. F., Rogers, K., Sharp, F., Longo, W. E., Vernava, III, A. M., Wade, T. P., Coplin, M. A., Virgo, K. S., Johnson, F. E., Brady, M., Kavolius, J., Quan, S. H. Q., Goldstein, E. T., Feldman, S., Shub, H. A., Bennett, D. R., Kumar, R., McMillen, M. A., Thornton, S., Khoury, D. A., Opelka, F. G., Teoh, T -A., Cohen, S. M., Weiss, E. G., Ortiz, H., De Miguel, M., Armendáriz, P., Rodriguez, J., Chocarro, C., Farouk, R., Dorrance, H. R., Duthie, G. S., Rainey, J. B., Morgado, Jr., P. J., Corman, M. L., Kawamura, Y. J., Sawada, T., Muto, T., Nagai, H., Hill, J., MacLennan, I., Binderow, S. R., Daniel, N., Ehrenpreis, E. D., Jensen, J. E., Bonner, G. F., Ruderman, W. B., Milsom, J. W., Gibbs, D. H., Beck, D. E., Hicks, T. C., Timmcke, A. E., Gathright, Jr, J. B., Cheong, D., Lucas, F. V., McGinity, M., Taylor, B. A., Godwin, P., Holdsworth, P., Lewis, W., Quirke, P., Williamson, M., Kokoszka, J., Pavel, D., Abcarian, H., Stephenson, B. M., Morgan, A. R., Salaman, J. R., Wheeler, M. H., Tran, T. C. K., Willemsen, W., Kuijpers, H. C., Lehman, J. F., Wiseman, J. S., MacFie, J., Sedman, P., May, J., Mancey-Jones, B., Johnstone, D., Nwariaku, F. E., Rochon, R. B., Huber, P. J., Carrico, C. J., Ortega, A., Beart, R., Winchester, D., Steele, G., Green, R., Caushaj, P. F., Devereaux, D., Griffey, S., Reiver, D., Kmiot, W. A., Baker, R., Luchtefeld, M. A., Anthone, G., Schlinkert, R., Roig, J. V., Villoslada, C., Solana, A., Alos, R., Hinojosa, J., Lledo, S., Johnson, D. R. E., Buie, W. D., Jensen, L. L., Heine, J., Hoffmann, B., Timmcke, A., Hicks, T., Opelka, F., Beck, D., Sousa, Jr., A., AraÚjo, S. A., Damico, F. M., Cordeiro, A. C., Pinotti, H. W., Gama, A. H., Fengler, S., Pearl, R., Orsay, C., Seow-Choen, F., Ho, J. M. S., Wiltz, O. H., Torregrosa, M., Brasch, R. C., Bufo, A. J., Krienberg, P., Johnson, G. P., Gowen, G. F., Mullen, P. D., Behrens, D., Hughes, T. G., Wynn, M., Pollack, J. S., Rajagopal, A. S., Huynh, T., Schanbacher, C., Hickson, W. G. E., Yang, Y. -K., Heymen, S., Choi, S. -K., Teoh, T. -A., Wexner, S. D., Vaccaro, C. A., Teoh, T. A., Nogueras, J. J., Choi, S. K., Cheong, D. M. O., Salanga, V. D., MacDonald, A., Baxter, J. N., Finlay, I. G., Mellgren, A., Bremmer, S., Dolk, A., Gillgren, P., Johansson, C., Ahlbäck, S. O., Udén, R., Holmström, B., Ferrara, A., O'Donovan, S., Larach, S. W., Williamson, P. R., Neto, J. A. Reis, Ciquini, S., Quilici, F. A., Reis, Jr., J. A., Torrabadella, L., Salgado, G., Whelan, R. L., Horvath, K. D., Golub, R., Ahsan, H., Cirocco, W., Ziv, Y., Fazio, V. W., Oakley, J. R., Church, J. M., Milsom, J. W., Lavery, L. C., Cohen, S. M., Kmiot, W. A., Reiver, D., Reissman, P., Weiss, E. G., Alós, R., García-Granero, E., Roig, J. V., Uribe, N., Sala, C., Lledo, S., Ozuner, G., Strong, S. A., Bufo, A. J., Daniels, G., Lieberman, R. C., Feldman, S., Lucas, F. V., Longo, W. E., Polites, G., Deshpande, Y., Vernava, A. M., Niehoff, M., Chandel, B., Berglund, D. D., Madoff, R. D., Gemlo, B. T., Spencer, M. P., Goldberg, S. M., Lowry, A. C., Marcello, P. W., Roberts, P. L., Schoetz, D. J., Murray, J. J., Coller, J. A., Veidenheimer, M. C., Koltun, W. A., Bloomer, M. M., Colony, P., Ruggeiro, F., Fleshner, P. R., Michelassi, F., Lewis, W., Williamson, M., Holdsworth, P., Finan, P., Ash, D., Johnston, D., Moran, M. R., Ramos, A., Rothenberger, D. A., Antonenko, D. R., Khanduja, K. S., Fitzgerald, S. D., Meagher, A. P., Moniz-Pereira, P., Wolff, B. G., Outwater, E. K., Marks, G. J., Mohiuddin, M., Sagar, P. M., Hartley, M. N., Mancey-Jones, B., Sedman, P., May, J., MacFie, J., Holbrook, R. F., Rodriguez-Bigas, M. A., Ramakrishnan, K., Palmer, M. L., Petrelli, N. J., Takahashi, T., Nivatvongs, S., Batts, K. P., Lucas, S. W., Klein, S. N., Keidan, R. D., Bannon, J. P., Zhou, J., Armitage, N. C., Hunt, L. M., Robinson, M. H., Hugkulstone, C. E., Clarke, B., Vernon, S. A., Gregson, R. H., Hardcastle, J. D., Ryan, M., Dutta, S., Levine, A., Ortega, A., Anthone, G., Beart, R., Dominguez, J. M., Saclarides, T. J., Bolan, P., Bines, S. D., Adachi, M., Watanabe, T., Sawada, T., Okinaga, K., Muto, T., Hase, K., Shatney, C., Mochizuki, H., Johnson, D., Ure, T., Dehghan, K., Andrus, C. A., Daniel, G. L., D'Emilia, J. C., Rodriguez-Bigas, M., Suh, O. K., Brewer, D. A., Fung, C., Chapuis, P., Bokey, E. L., Garcia, J. C., Banerjee, S., Remzi, F. H., Lavery, I. C., Jorge, J. M. N., Ger, G. C., Gonzalez, L., Gee, A. S., Roe, A. M., Durdey, P., Kaye, M. D., Kyzer, S., Gordon, P. H., Hasegawa, M., Bun, P. Tae, Ikeuchi, D., Onodera, H., Imamura, M., Maetani, S., Blake, T., Hellinger, M., Grewal, H., Klimstra, D. S., Cohen, A. M., Guillem, J. G., Rooney, P. S., Gifford, K. -A., Clarke, P. A., Kuhn, J. A., Bryce, K., Frank, N., Dignan, R. D., Lichliter, W. E., Franko, E., Jacobson, R. M., Preskitt, J. T., Lieberman, Z., Tulanon, P., Steinbach, H., McCarty, T., Simons, T., Plasencia, G., Viamonte, M., Wiltz, O., Jacobs, M., Chen, W. S., Leu, S. Y., Hsu, H., Bessler, M., Halverson, A., Kayton, M. L., Treat, M. R., Nowygrod, R., Congilosi, S., Madoff, R., Wong, W. D., Rothenberger, D., Buie, W. D., Paterson, R., Cartmill, J. A., Trokel, M. J., Gingold, B. S., Cooper, M., Gorfine, S. R., Bauer, J. J., Gelernt, I. M., Kreel, I., Harris, M. T., Vallejo, J. F., Kestenberg, A., Miyajima, N., Kano, N., Ishikawa, Y., Sakai, S., Yamakawa, T., Otchy, D. P., Van Heerden, J. A., Ilstrup, D. M., Weaver, A. L., Winter, L. D., Mav, J., Lee, P. Y., Vetto, J. T., Sullivan, E. S., Rabkin, J., Mayoral, J. L., Matas, A. J., Bove, P., Visser, T., Barkel, D., Villalba, M., Bendick, P., Glover, J., Golub, R. W., Cirocco, W. C., Daniel, N., Altringer, W., Domingues, J. M., Brubaker, L. T., Smith, C. S., Kumar, S., and Gilbert, P.

Published
1994
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14. Podium presentations

Author

Foley, E. F., Marcello, P. W., Roberts, P. L., Murray, J. J., Coller, J. A., Veidenheimer, M. C., Schoetz, D. J., McIntyre, P. B., Pemberton, J. H., Wolff, B. G., Beart, Jr., R. W., Kelly, K. A., Dozois, R. R., Sugita, A., Fukushima, T., Harada, H., Yamamoto, M., Shimada, H., Tjandra, J. J., Fazio, V. W., Milson, J. W., Lavery, I. C., Oakley, J. R., Fabre, J. M., Karch, L. A., Bauer, J. J., Gorfine, S. R., Gelernt, I. M., Metcalf, A. M., Varilek, G., Keck, J. O., Hoffmann, D. C., Sgambati, S. A., Sardella, W. V., Marts, B. C., Longo, W. E., Vernava, III, A. M., Kennedy, D. J., Daniel, G. L., Jones, I., Venkatesh, K. S., Diamond, L. W., Larson, D. M., Ramanujam, P. J., Hicks, J. R., Ellis, C. N., Blakemore, W. S., Nathanson, S. D., Linden, M. D., Tender, P., Zarbo, R. J., Nelson, L., Bannon, J., Marks, G., Zhou, J., Mohiuddin, M., Marks, J., Pollard, C. W., Nivatvongs, S., Rojanasakul, A., Ilstrup, D. M., Speziale, N. J., Saclarides, T. J., Rubin, D. B., Szeluga, D. J., Morgado, P. J., Gomez, L. G., Morgado, Jr., P. J., Neto, J. A. Reis, Quilici, F. A., Cordeiro, F., Reis, Jr., J. A., Nitecki, S., Benn, P., Sarr, M. G., Weiland, L. H., Elhadad, A., Rouffet, F., Baillet, P., Akasu, T., Moriya, Y., Hojo, K., Sugihara, K., Oshima, H., Liu, S. K., Church, J. M., Kirkpatrick, J. R., Danielson, C. L., Dominguez, J. M., Jakate, S. M., Savin, M. H., Altringer, W. J., Lee, C. S., Spencer, M. P., Madoff, R. D., Barrett, R. C., Oster, M. A., Durdey, P., Stein, B. L., Staniunas, R. J., Grewal, H., Guillem, J. G., Quan, S., Enker, W. E., Cohen, A. M., van Tets, W. F., Kuijpers, H. C., Kerner, B. A., Wise, Jr., W. E., Golub, R. W., Arnold, M. W., Aguilar, P. S., Pernikoff, B. J., Eisenstat, T. E., Rubin, R. J., Oliver, G. C., Salvati, E. P., Lunniss, P. J., Sultan, A. H., Barker, P. G., Armstrong, P., Bartram, C. I., Phillips, R. K. S., Schouten, W. R., Briel, J. W., Auwerda, J. J. A., Harnsberger, J. R., Robbins, P. L., Brabbee, G. W., Ryhammer, A. M., Bek, K. M., Hanberg-Sørensen, F., Laurberg, S., Hoff, S. D., Bailey, H. R., Butts, D. R., Max, E., Smith, K. W., Zamora, L. F., Skakun, G. B., Khanduja, K. S., Lee, H., Beart, R. W., Spencer, R., Wiseman, J. S., Senagore, A. J., Bain, I. M., Oliff, J., Min, L., Neoptolomos, J., Keighley, M. R. B., O'Kelly, T. J., Davies, J., Brading, A. F., Mortensen, N. J. McC, Park, J. -G., Han, H. J., Kang, M. S., Nakamura, Y., Goldberg, G. S., Orkin, B. A., Smith, L. E., Fleshner, P. R., Freilich, M. I., Meagher, A. P., Adams, W. J., Lubowski, D. Z., King, D. W., Moran, M., Opelka, F., Timmcke, A., Hicks, T., Gathright, Jr., J. B., Leu, S. Y., Hsu, H., Dean, P. A., Ramsey, P. S., Nelson, H., Philpott, G., Siegel, B., Schwarz, S., Fleshman, J., Welch, M., Connett, J., Buie, W. D., Johnson, D. R., Heine, J. A., Wong, W. D., Rothenberger, D. A., Goldberg, S. M., Shafik, A., MacDonald, A., Craig, J. W., Finlay, I. G., Baxter, J. N., Muir, T. C., Parikh, S., Gold, R. P., Gottesman, L., Annibali, R., Öresland, T., Hallgren, T., Fasth, S., Hultén, L., Farouk, R., Duthie, G. S., MacGregor, A. B., Bartolo, D. C. C., Williamson, M. E. R., Lewis, W. G., Holdsworth, P. J., Hall, N., Finan, P. J., Johnston, D., Seow-Choen, F., Goh, H. S., Motson, R. W., Walsh, C. J., Mooney, E., Yamashita, H. J., Wise, W. E., Hartmann, R. F., Seccia, M., Menconi, C., Ghiselli, G., Cavina, E., Salomon, M. C., Ferrara, A., Larach, S. W., Williamson, P. R., Bass, E. M., Orsay, C. P., Firfer, B., Ramakrishnan, V., Abcarian, H., Bufo, A. J., Feldman, S., Daniels, G. A., Lieberman, R. C., Loder, P. B., Kamm, M. A., Nicholls, R. J., Kum, C. K., Ngoi, S. S., Goh, P. M. Y., Tekant, Y., Isaac, J. R., Gerstle, J. T., Kauffman, G. L., and Koltun, W. A.

Published
1993
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15. Observations of Intermediate-Scale Diurnal Waves in the Equatorial Mesosphere and Lower Thermosphere

Author

Lieberman, R. S, Riggin, D. M, Garcia, R. R, Wu, Qian, and Remsberg, E. E

Subjects
Geophysics
Abstract

The purpose of this study is to seek observational evidence for diurnal, vertically propagating inertia-gravity waves (IGWs) in the mesosphere and lower thermosphere (MLT). Numerical modeling studies indicate that vertically propagating IGWs excited by tropical heating provide a significant source of momentum for the semiannual oscillation (SAO) in the equatorial zonal mean winds. The power spectrum of these waves has a strong diurnal component. We analyze global patterns of ascending and descending node differences in MLT satellite temperatures, which are assumed in this study to be proxies for waves of diurnal period. Juxtaposed upon the planetary-scale features are localized variations with longitudinal wavelengths ranging from 25 deg to 50 deg, and with vertical wavelengths between 13 and 25 km. These intermediate-scale variations are spatially coherent, and persist for several weeks. Their amplitudes generally increase with altitude, while their phase structures suggest both eastward and westward propagation. The variance of wave numbers 9-17 in the MLT is examined in relation to the underlying stratospheric zonal mean zonal gradient winds. Stronger variances generally coincide with periods where the underlying zonal mean winds are relatively light, or unidirectional. The weak inverse association between variance strength and zonal wind magnitude is suggestive of a wave filtering mechanism.

Published
2006
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18. Development of an Early Warning Fire Detection System using Correlation Spectroscopy

Author

Goswami, K, Voevodkin, G, Rubstov, V, Lieberman, R, and Piltch, N

Subjects
Inorganic, Organic And Physical Chemistry
Abstract

Combustion byproducts are numerous. A few examples of the gaseous byproducts include carbon dioxide, carbon monoxide, hydrogen chloride, hydrogen cyanide and ammonia. For detecting these chemical species, classic absorption spectroscopy has been used for many decades, but the sensitivity of steady-state methods is often unsuitable for the detection of trace compounds at the low levels (parts per million to parts per billion) appropriate for scientific purposes. This is particularly so for monitoring equipment, which must be compact and cost-effective, and which is often subjected to shock, vibration, and other environmental effects that can severely degrade the performance of high-sensitivity spectrometers in an aircraft. Steady-state techniques also suffer from a lack of specificity; the deconvolution of the spectra of complex mixtures is a laborious and error prone process. These problems are exacerbated in remote fiber-optic monitoring where, for practical reasons, the fundamental absorbance region of the spectrum (often between 3 and 8 microns) is inaccessible, and the low-strength, closely spaced, near-infrared overtone absorbance bands must be used. We circumvented these challenges by employing correlation spectroscopy, a variation of modulation spectroscopy.

Published
2001

23. The Role of Inertial Instability in Cross-Hemispheric Coupling.

Author

Lieberman, R. S., France, J., Ortland, D. A., and Eckermann, S. D.

Subjects
*NOCTILUCENT clouds, *OZONE layer, *ROSSBY waves, *STRESS waves, *STRATOSPHERE
Abstract

Recent studies suggest linkages between anomalously warm temperatures in the winter stratosphere, and the high-latitude summer mesopause. The summer temperature anomaly is manifested in the decline of polar mesospheric clouds. The 2-day wave is a strong-amplitude and transient summer feature that interacts with the background state so as to warm the high-latitude summer mesopause. This wave has been linked to a low-latitude phenomenon called inertial instability, which is organized by breaking planetary waves in the winter stratosphere. Hence, inertial instability has been identified as a possible nexus between the disturbed winter stratosphere, and summer mesopause warming. We investigate a sustained occurrence of inertial instability during 19 July–8 August 2014. During this period, stratospheric winter temperatures warmed by about 10 K, while a steep decline in polar mesospheric clouds was reported between 26 July and 6 August. We present, for the first time, wave driving associated with observed inertial instability. The effect of inertial instability is to export eastward momentum from the winter hemisphere across the equator into the summer hemisphere. Using a primitive equation model, we demonstrate that the wave stresses destabilize the stratopause summer easterly jet. The reconfigured wind profile excites the wavenumber-4 component of the 2-day wave, leading to enhanced warming of the summer mesopause. This work supports previous numerical investigations that identified planetary wave–driven inertial instability as a source of the 2-day wave. [ABSTRACT FROM AUTHOR]

Published
2021
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25. Observations of the diurnal tide from space

Author

Hays, Paul B, Wu, D. L, Burrage, M. D, Gell, D. A, Grassl, H. J, Lieberman, R. S, Marshall, A. R, Morton, Y. T, Ortland, D. A, and Skinner, W. R

Subjects
Geosciences (General)
Abstract

This study presents a climatology of mesospheric and lower-thermospheric diurnal tidal winds obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS). The observations reveal that although tidal structures are present at all times, like the prevailing zonal winds, they exhibit significant semiannual as well as other shorter-term variations in amplitude. Results are presented for a period extending over more than one year from November 1991 to July 1993. The 1,1 diurnal tidal amplitude of the meridional component, characterized by the value at an altitude of 90 km and a latitude of 22 deg, ranges from a minimum at solstice of less than 20 m per sec to an equinox maximum of over 70 m per sec. The vertical wavelength and phase of the tide show only slight variations throughout the year, with a suggestion of semiannual variations in both.

Published
1994
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26. Observations of the quasi 2-day wave from the High Resolution Doppler Imager on UARS

Author

Wu, D. L, Hays, P. B, Skinner, W. R, Marshall, A. R, Burrage, M. D, Lieberman, R. S, and Ortland, D. A

Subjects
Geophysics
Abstract

A strong westward traveling oscillation, with a period of 2 days and zonal wave number 3, is observed in the mesospheric and lower thermospheric winds from the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS). The important events happen in January, July, and September/October, of which the occurrence in January is the strongest with an amplitude over 60 m/s. Detailed analyses for the periods of January 1992 and January 1993 reveal a cause-and-effect relationship in the wave developing process at 95 km. The global structures of the wave amplitude and phase are also presented.

Published
1993

27. Zonal mean winds in the equatorial mesosphere and lower thermosphere observed by the High Resolution Doppler Imager

Author

Lieberman, R. S, Burrage, M. D, Gell, D. A, Hays, P. B, Marshall, A. R, Orthland, D. A, Skinner, W. R, Wu, D. L, Vincent, R. A, and Franke, S. J

Subjects
Geophysics
Abstract

This paper presents analyses of mesospheric and lower thermospheric zonal mean winds observed by the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS). Monthly averages of the equatorial zonal mean zonal winds are presented for January 1992 through June 1993. Equatorial zonal winds in the 70-90 km region are dominated by a semiannual oscillation (SAO), ranging from 30 m/s (westerly) to -100 m/s (easterly). At high latitudes the zonal wind variations are predominantly annual. Above 90 km, the low-latitude flow is easterly at all times, punctuated by a small semiannual variation. This behavior may be related to the deposition of momentum by the diurnal tides.

Published
1993

28. Comparison of HRDI wind measurements with radar and rocket observations

Author

Burrage, M. D, Skinner, W. R, Marshall, A. R, Hays, P. B, Lieberman, R. S, Franke, S. J, Gell, D. A, Ortland, D. A, Morton, Y. T, and Schmidlin, F. J

Subjects
Meteorology And Climatology
Abstract

Wind fields in the mesosphere and lower thermosphere are obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) by observing the Doppler shifts of emission lines in the O2 Atmospheric band. The validity of the measured winds depends on an accurate knowledge of the positions on the detector of the observed lines in the absence of a wind-induced Doppler shift. These positions have been determined to an accuracy of approximately 5 m/s from the comparison of winds measured by HRDI with those obtained by MF radars. Excellent agreement is found between HRDI measured winds and winds observed with radars and rockets. In addition, the sensitivity of HRDI to migrating tides and other large scale waves is demonstrated.

Published
1993

29. Optical fiber sensors for life support applications

Author

Lieberman, R. A, Schmidlin, E. M, Ferrell, D. J, and Syracuse, S. J

Subjects
Instrumentation And Photography
Abstract

Preliminary experimental results on systems designed to demonstrate sensor operation in regenerative food production and crew air supply applications are presented. The systems use conventional fibers and sources in conjunction with custom wavelength division multiplexers in their optical signal processing sections and nonstandard porous optical fibers in the optical sensing elements. It is considered to be possible to create practical sensors for life-support system applications, and particularly, in regenerative food production environments, based on based on reversible sensors for oxygen, carbon monoxide, and humidity.

Published
1992

30. Communication Strategies Used By Language-Impaired and Language-Normal Children.

Author

Lieberman, R. Jane and Hutchinson, Edward C.

Abstract

The acquisition of communicative competence is explored in a study of the emergence of functional use of language among early school-aged children. Cognitive communication strategies and language use in the context of early academic success or lack of success are discussed. Results are presented. (DF)

Published
1984

31. Content Relevance and Content Coverage in Tests of Grammatical Ability.

Author

Lieberman, R. Jane and Michael, Ann

Abstract

Three tests of grammatical ability (Carrow Elicited Language Inventory, Test of Language Development, and Clinical Evaluation of Language Functions) were evaluated for content-oriented test construction. Content domains were found deficient when judged against an external standard as well as when examined according to their own content specifications. (Author/CL)

Published
1986

32. A Comparison of Four Adolescent Language Tests.

Author

Lieberman, R. Jane

Abstract

While no significant differences were found for sixth-graders' (N=30) performance on the Fullerton Test for Adolescents, Test of Adolescent Language, and the Clinical Evaluation of Language Functions, significantly fewer students were identified as needing further evaluation by the Screening Test of Adolescent Language than by the other three tests. (Author/CB)

Published
1987

36. Feasibility of Long-Term Outcomes Measurement by Residential Providers.

Author

Weiner, Dana, Lieberman, R. E., Huefner, J. C., Thompson, R., McCrae, J., and Blau, G.

Subjects
*RESIDENTIAL care, *BEST practices, *PROBLEM youth, *INSTITUTIONAL care, *CAREGIVERS
Abstract

Policy makers and funders working to address best practices for residential care and treatment require evidence for the effectiveness of residential interventions, particularly related to maintenance of effects post-discharge. With support from the Substance Abuse and Mental Health Services Administration of the US Department of Health and Human Services, the Building Bridges Initiative and providers of residential interventions partnered with Chapin Hall to study the feasibility of a method for collecting follow-up data on the functioning of young people who were recently discharged from residential treatment. This paper describes the implementation and findings regarding the feasibility of (1) identifying the location of youth 6 months post-discharge, (2) contacting the caregivers of these youth for the purpose of administering a follow-up survey, and (3) administering a brief (10-min) survey inquiring about youth functioning in key domains. The results of this research provide guidance for measuring youth progress and outcomes after residential interventions. This study also lays the groundwork for a larger post-discharge outcomes study that includes linkage to administrative data, baseline data on youth functioning, and assessment of the services received in the context of residential interventions. Data and information obtained from the feasibility study provide evidence for the viability of a brief, telephone-administered post-discharge survey with caregivers. [ABSTRACT FROM AUTHOR]

Published
2018
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37. Local and Remote Planetary Wave Effects on Polar Mesospheric Clouds in the Northern Hemisphere in 2014.

Author

France, J. A., Randall, C. E., Lieberman, R. S., Harvey, V. L., Eckermann, S. D., Siskind, D. E., Lumpe, J. D., Bailey, S. M., Carstens, J. N., and Russell, III, J. M.

Abstract

Abstract: Observations by the Cloud Imaging and Particle Size (CIPS) instrument on the Aeronomy of Ice in the Mesosphere (AIM) satellite show an anomalous decline in Northern Hemisphere polar mesospheric clouds (PMCs) from 26 July to 6 August 2014. The decline is attributed to local warming associated with the quasi‐two‐day wave and interhemispheric coupling (IHC) triggered by planetary wave breaking in the Antarctic (winter) stratosphere. The results indicate that the IHC in 2014 occurred via a pathway that previous studies have not emphasized. Based on observations from the Aura Microwave Limb Sounder (MLS) and reanalyses from both the Modern‐Era Retrospective analysis for Research and Applications, Version 2 (MERRA‐2) and the Navy Global Environmental Model (NAVGEM), we argue that a strengthening of the summer easterly jet gave rise to enhanced meridional and vertical shear along its equatorward flank, which supported growth of the two‐day wave. The two‐day wave led to enhanced meridional mixing in northern midlatitudes and a weakening of the northern branch of the mesospheric residual circulation, reducing ascent and warming the polar summer mesopause. In 2014, the five‐day planetary wave modulated the response to IHC such that PMCs persisted in its cold phases even though zonal mean temperatures were too high to support PMCs, and were absent in the warm phases when zonal mean temperatures were low enough to support PMCs. [ABSTRACT FROM AUTHOR]

Published
2018
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38. The Contributions of Phonological Awareness, Alphabet Knowledge, and Letter Writing to Name Writing in Children With Specific Language Impairment and Typically Developing Children.

Author

Pavelko, Stacey L., Lieberman, R. Jane, Schwartz, Jamie, and Hahs-Vaughn, Debbie

Subjects
*CONFIDENCE intervals, *STATISTICAL correlation, *INTELLECT, *LANGUAGE acquisition, *LANGUAGE disorders, *LITERACY, *PHONETICS, *PROBABILITY theory, *T-test (Statistics), *INTER-observer reliability, *DATA analysis software, *DESCRIPTIVE statistics, *CHILDREN, WRITING
Abstract

Purpose: Name writing is one aspect of emergent writing that has been used to understand emergent literacy development. Name-writing skills and the relationship of name writing to other emergent literacy skills have not been studied extensively in children with specific language impairment (SLI). Children with SLI consistently demonstrate delays in phonological awareness (PA), alphabet knowledge (AK), print awareness, and emergent writing. The purpose of this study was to examine the contributions of PA, AK, and letter writing to name writing in children with SLI and typically developing (TD) children. Method: Participants were 65 children (22 SLI, 43 TD) with an average age of 53 months. Participants completed the Assessment of Literacy and Language (Lombardino, Lieberman, & Brown, 2005), a letter-writing task, and a name-writing task. Results: Data were analyzed using correlation and mediation modeling. Mediation modeling, a more sophisticated analysis, revealed that PA, AK, and letter writing, in serial, were mediating variables for language status on name writing. Conclusion: Phonemic awareness, AK, and letter writing help to explain the relationship between language status and name writing. These skills should be integrated during treatment, using a horizontal approach with developmentally appropriate activities, particularly for children with SLI. [ABSTRACT FROM AUTHOR]

Published
2018
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39. The development of writing skills in 4-year-old children with and without specific language impairment.

Author

Pavelko, Stacey L., Lieberman, R. Jane, Schwartz, Jamie, Hahs-Vaughn, Debbie, and Nye, Chad

Subjects
*ABILITY, *CONFIDENCE intervals, *INTELLIGENCE tests, *LANGUAGE disorders, *QUESTIONNAIRES, *T-test (Statistics), *TRAINING, *EFFECT sizes (Statistics), *DATA analysis software, *MEDICAL coding, *DESCRIPTIVE statistics, WRITING
Abstract

Research shows that many preschool children with specific language impairment (SLI) have difficulty acquiring literacy skills including phonological awareness, print concepts, and alphabet knowledge. Limited research suggests that preschool children with SLI also have difficulty with emergent writing tasks such as name writing and word writing. In typically developing children, research indicates that emergent writing skills are acquired in a developmental sequence: (1) linearity, (2) segmentation, (3) simple characters, (4) left-right orientation, (5) complex characters, (6) random letters, and (7) invented spelling. This study compared the emergent writing skills of 4-year-old children with SLI (n = 22) to their age- and gender-matched peers (n = 22). Results indicated that children with SLI demonstrate difficulty with a variety of writing tasks, including letter writing, name writing, word writing, and sentence writing when compared to their typically-developing peers. Children with SLI followed the same developmental sequence in acquiring writing skills as their typically-developing peers. [ABSTRACT FROM AUTHOR]

Published
2017
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42. Safety of intravitreous fomivirsen for treatment of cytomegalovirus retinitis in patients with AIDS

Author

Boyer, D. S., Cowen, S. J., Danis, R. P., Diamond, J. G., Fish, R. H., Goldstein, D. A., Jaffe, G. J., Lalezari, J. P., Lieberman, R. M., Belfort, R., Muccioli, C., Palestine, A. G., Perez, J. E. A., Territo, C., Andreu-Andreu, D., Deschennes, J. G., de Smet, M. D., Fisher, M., Gastaut, J. A., Gazzard, B. G., Lightman, S., Johnson, M. A., Klauss, V., Gumbel, H., Knospe, V., Mallolas-Masferrer, J., Cornish, M. J., Holland, G. N., Ransome, S. S., Tufail, A., Weisz, J. M., Crooke, S. T., Kishner, D. L., Frost, K. R., Hutscherson, S. L., Whitley, R. J., Chandler, J. W., Grillone, L. R., Hutcherson, S. L., Lanz, R., and Ophthalmology

Published
2002

43. Randomized dose-comparison studies of intravitreous fomivirsen for treatment of cytomegalovirus retinitis that has

Author

Boyer, D. S., Cowen, S. J., Danis, R. P., Diamond, J. G., Fish, R. H., Goldstein, D. A., Jaffe, G. J., Lalezari, J. P., Lieberman, R. M., Belfort, R., Muccioli, C., Palestine, A. G., Perez, J. E. A., Territo, C., Andreu-Andreu, D., Deschennes, J. G., de Smet, M. D., Fisher, M., Gastaut, J. A., Gazzard, B. G., Lightman, S., Johnson, M. A., Klauss, V., Gumbel, H., Knospe, V., Mallolas-Masferrer, J., Cornish, M. J., Holland, G. N., Ransome, S. S., Tufail, A., Weisz, J. M., Crooke, S. T., Kishner, D. L., Frost, K. R., Hutscherson, S. L., Whitley, R. J., Chandler, J. W., Grillone, L. R., Hutcherson, S. L., Lanz, R., and Ophthalmology

Published
2002

44. Florida program spotlights language and literacy; speech-language students add a focus on reading

Author

Lieberman, R. Jane and Rosa-Lugo, Linda I.

Subjects
University of Central Florida -- Services, University of Central Florida -- Curricula, Literacy programs -- Evaluation, Speech therapists -- Practice, Audiologists -- Practice, Language disorders -- Care and treatment
Abstract

In 2004 the Department of Communication Sciences and Disorders (DCSD) at the University of Central Florida (UCF) in Orlando began offering specialized coursework and practicum experiences to prepare students to [...]

Published
2007

45. Characterization of uterine epithelium apoptotic cell death kinetics and regulation by progesterone and RU 486

Author

Rotello, R. J., Lieberman, R. C., Lepoff, R. B., and Gerschenson, L. E.

Subjects
Mifepristone, Cell Death, Uterus, Animals, Epithelial Cells, Female, DNA, Rabbits, Progesterone, Research Article
Abstract

The authors show here that progesterone suppresses apoptosis, and its antagonist RU 486 induces it in rabbit uterine epithelium, as assessed by morphologic and biochemical studies. The authors' studies demonstrate that internucleosomal DNA fragments are identifiable as early as 24 hours after ovariectomy of pseudopregnant rabbits, and become undetectable 6 days after ovariectomy. Maximal levels of DNA fragmentation (about 74% of total isolated DNA) were observed 36 hours after ovariectomy. The number of apoptotic cells appeared to increase parallel to the increased DNA breakdown, and accounted for approximately 26% of the uterine epithelial cells at 48 hours after ovariectomy. Levels of progesterone in serum dropped precipitously 6 hours after ovariectomy and remained very low for several days. Administration of progesterone, more than any other steroid hormone, to pseudopregnant ovariectomized rabbits, prevented the increase in apoptotic cell death. By contrast, administration of the anti-progestin RU 486 to pseudopregnant rabbits triggered apoptosis, which attained levels similar to those observed in ovariectomized animals. The authors' findings establish that uterine epithelium apoptosis occurs in a time-dependent fashion and provides strong evidence that the actions of progesterone in that tissue are not only to stimulate cell proliferation and differentiation, but also to suppress apoptosis.

Published
1992

46. Evaluation of a Novel 'Intelligent' Dosing System for Optimizing FK 506 Therapy

Author

Mcmichael, J., Irish, W., Mccauley, J., Shapiro, R., Gordon, R., Thiel, D. H., Lieberman, R., Warty, V. S., John Fung, and Starzl, T. E.

Subjects
Artificial Intelligence, Humans, Prospective Studies, Kidney Transplantation, Models, Biological, Article, Algorithms, Tacrolimus, Liver Transplantation
Published
1991

47. Topologies on directed graphs

Author

Lieberman, R. N

Subjects
Mathematics
Abstract

Given a directed graph, a natural topology is defined and relationships between standard topological properties and graph theoretical concepts are studied. In particular, the properties of connectivity and separatedness are investigated. A metric is introduced which is shown to be related to separatedness. The topological notions of continuity and homeomorphism. A class of maps is studied which preserve both graph and topological properties. Applications involving strong maps and contractions are also presented.

Published
1972

49. Insufficient methodologically-sound evidence exists for the use of computer-based interventions to teach communication skills to individuals with autism.

Author

Schwartz, Jamie B., Lieberman, R. Jane, and Nye, Chad

Subjects
MEANS of communication for people with disabilities, AUTISM spectrum disorders in children, ASSISTIVE technology, COMMUNICATIVE competence
Abstract

Ramdoss, S., Lang, R., Mulloy, A., Franco, J., O’Reilly, M., Didden, R., & Lancioni, G. (2011). Use of computer-based instructions to teach communication skills to children with autism spectrum disorders: A systemic review.Journal of Behavioral Education,20, 55–76. Sources of Funding and Declaration of Interests: No source of funding was reported and no conflicts of interests were reported. [ABSTRACT FROM PUBLISHER]

Published
2015
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