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Markus Furger, C. David Whiteman, and James M. Wilczak

the simulations To examine the effects of various measurement errors on the uncertainty of the heat budget equation, wefirst performed a control simulation. This control runserved as a basis for comparison with other scenariosin which one parameter at a time was varied, while allother parameters were kept fixed.a. Control run Our strategy lbr the simulations was to start withstationary and horizontally homogeneous temperature,wind, and radiation fields. In such a setting all horizontal

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Barry B. Ma and Jeffrey A. Nystuen

). The rainfall rate directly converted from the acoustic sound level has the potential for very high temporal resolution as the measurement is an instantaneous acoustic measure ( Nystuen and Amitai 2003 ). During the EPIC 2001 phase of the study, the underwater acoustic sensors—passive aquatic listeners [PALs; also known as acoustic rain gauges (ARGs)] were deployed at 10° and 12°N, 95°W and were in place for several years. Periods of rain and wind are identified through an acoustic discrimination

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J. E. Gaynor and P. A. Mandics

G. F. Dreyer, 1975: Effects of temperature and humidity fluctuations on the optical refractive index in the marine boundary layer. J. Opt. So6. Am~r., 65, 1502-1511.Gaynor, J. E., 1977: Acoustic Doppler measurement of atmo spheric boundary layer velocity structure functions and energy dissipation rates. J. Appl. Meteor., 16, 148-155.--, P. A. Mandics, A. B. Wahr and F. F. Hall, Jr., 1976: Studies of the tropical marine boundary layer using acoustic backscattering during GATE. t

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A. J. Bedard

1. Introduction This paper reviews the background of past measurements of acoustic energy at audible and infrasonic frequencies from severe weather and tornadoes. Infrasonic frequencies (i.e., sound below 20 Hz) can travel for great distances without significant absorption. Whereas a 1 kHz signal will have 90% of its energy absorbed after traveling 7 km at sea level, for a 1-Hz signal this distance is 3000 km ( Cook 1962 ). Background concerning the measurements provided by infrasonic observing

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Dimitris Menemenlis and Michael Chechelnitsky

H , and also possibly in the measurement error covariance matrix, R . These are readily accommodated by using a Monte Carlo approach to compute the Green’s functions, G [xe3] D , k . An example of this approach, with a time-varying H ( t ), is the treatment of acoustic time series of differing lengths in section 4 . The second type of time dependence is fluctuations of the “unknown” model parameters, α k ( t ) in (6) , (7) . In principle, this situation can be addressed through piecewise

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Peter G. Black, John R. Proni, John C. Wilkerson, and Christopher E. Samsury

submerged to a depth of 1.5 m, which provided a surface monitoring area with a radius of about 4.5 m. Contributions from bottom and boundary reflection effects resulting from the very shallow depth of the pond may be present but are thought to be negligible. Acoustic data were sampled at 100 kHz and processed as FFT (fast Fourier transform) spectra to 50 kHz. Surface wind and rain measurements were made with an anemometer and a rain gauge mounted on a fixed platform in the pond, 6 m from the hydrophone

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. F.), "Ma~s Waves: 3. Changes in the Densities of the Different Ion Species,"Property Variablility in Three Closely Spaced Deep-sea Sediment Journal of Geophysical Research, Space Physics, Val. 75, No. 34,Cores," Journal of Sedimentary Petroleum, Vol. 40, No. 3, Sept. Dec. 1, 1970, pp. 7239-7243.1970, pp. 1038-1043. Hooke, William H. (with Hines, C. Q.), "Discussion of IonizationBouricius, G. M. B., and Clifford, S. F., "An Optical Interferometer Effects on the Propagation of Acoustic

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J. E. Gaynor and C. F. Ropelewski

undisturbed situations (e.g.,Wylie, 1976; Emmitt, 1978). The recent efforts ofZipser (1977) and Houze (1977) have combinedradar, surface, tethered sonde and radiosonde profiles, and aircraft and acoustic sounder data in anattempt to look at the total picture of precipitatingconvection in GATE. Not only did they study theevolution of individual convective elements within amesoscale structure, but they also looked at someof the effects of this convection on the entire troposphere, including the boundary

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Peter T. May and James M. Wilczak

) ABSTRACT A wind profiler-radio acoustic sounding system at Denver collected hourly wind and virtual-temperaturedata through the boundary layer in the latter half of 1989. Analyzed monthly averages of 24-h time-heightcross sections of the daily measurements show a number of significant features. The growth of the nocturnaltemperature inversion is observed, followed by a rapid transition to a deep daytime mixed layer. The progressionfrom a strong diurnal temperature signal in the summer to weak

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William C. Skamarock and Joseph B. Klemp

physicalinterest often are of much lower frequency than thehighest-frequency modes admitted by the equations,such as high-frequency gravity and acoustic modes,that are meteorologically unimportant. Numerical techniques used to integrate the equations are often timestep limited by these irrelevant modes, and a popularintegration approach is to integrate the high-frequencycomponents with a smaller time step, or with an implicit technique, while integrating the lower-frequencycomponents with an explicit scheme

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