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Ren-Chieh Lien, Michael J. McPhaden, and Dave Rebert

Science, Oregon &ate University, Corvallis, Oregon(Manuscript received 7 May 1993, in final form 28 Januar~ 1994)ABSTRACT Three sets of horizontal velocity measurements obtained within 3 miles of each other at 0-, 140-W arecompared. Measurements were taken by acoustic Doppler current profilers (ADCPs) on different platforms, .with different tracking filter configurations, and were processed by three different group~ Averaged over morethan 12 days, mean velocity measurements differ by less than

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G. A. Davidson

).REFERENCESCole, J. E., and R.A. Dobbins, 1970: Propagation of sound through atmospheric fog. Y. Atmos. S-i., 27, 426-434. , and , 1971: Measurements of the attenuation of sound by a warm air fog. J. Atmos. S-i., 28, 202-209.Davidson, G. A., and D. S. Scott, 1973: Finite-amplitude acoustics of aerosols. J. A -oust. So~. A mer., 53, 1717-1729.Einaudi, F., and D. P. Latas, 1973: The propagation of acoustic gravity waves in a moist atmosphere. J. Atmos. S-i., 30, 365 376.Marble, F. E., 1969: Some

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Shixuan Pang and Hartmut Graßl

-phase precipitation. a. Using high-frequency sodars to simultaneously measure precipitation and turbulence Doppler spectra Microwave remote sensing techniques for rainfall measurements suffer from effects by the unknown mean vertical wind velocity ( w ) and spectral broadening ( Atlas et al. 1973 ; Lee 1988 ; Gossard et al. 1990 ; Wakasugi et al. 1986 , 1987 ; Ulbrich 1992 ; Pang and Grassl 1994 , 1995 ). To correct such effects, the Doppler spectra of precipitation and turbulence need to be measured

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R. L. Coulter and M. L. Wesely

-correlationgear was mounted 11 m above the surface on a boomextending 4 m from the southwest corner of thetower. This orientation necessitated a choice of winddirection from about 135 to 360-, to eliminate undesirable tower-wind effects. Simultaneous measurements were taken of eddycorrelation fluxes of heat and momentum, line integrals of optical C,? weighted nonlinearly overpaths which were within the surface layer, and volume averages (in a narrow column 17 m in height)of acoustic C,? in the lower PBL, at

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Brian D. Dushaw, Peter F. Worcester, Bruce D. Cornuelle, and Bruce M. Howe

September 1987. The accuracy of acoustical measurements ofrange-averaged heat content is comparable to estimates from CTD and XBT data. Transmissions at four-dayintervals allow the continuous observation of heat content and show that it varies on time scales of weeks orless. The magnitude of these variations is of the same order as that observed from XBT sections, which are onlyoccasionally available. Ocean-atmosphere heat exchange from bulk formulas accounts for only about half ofthe observed heat

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John E. Cole III and Richard A. Dobbins

thermal relaxation time for the droplet, ~o the circular acoustic frequency, and C,, the liquidmass fraction), near unity where the effects of mass transfer are dominant. The tests are made in a Wilsoncloud chamber by measuring the rate of decay of the fundamental mode of acoustic oscillation which isexcited during the operation of the chamber. Measurements of pressure and volume are made continuouslyduring the expansion. Droplet size and concentration of the monodisperse fog are determined from

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D. Hurther and U. Lemmin

constant beamwidth transducer system, which is capable of generating an extended focal zone by electronically focusing the beam over the desired water depth range. The sample volume has a constant width (∼7 mm from −6 dB acoustic beam measurements) over a range of 60 cm. Due to this configuration, the effects of process 2 and variance 4 cited in the introduction can be significantly reduced. Four 1-MHz large angle receivers are placed symmetrically around the emitter ( Fig. 1a ). They are used to

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Friedrich Schott

profilers (ADCPs), in particularfor studying surface-mixed-layer dynamics from underneath, would be to combine them with a thermistor cablefor obtaining simultaneous current and temperature profiles. Measurements with an ADCP, operating at 150kHz and sampling at 2.2 m vertical bin lengths, were carried out from a barge moored in Lake San Vincente,California, over a water depth of 45 m, to investigate the effects of a thermistor string running along the axisof the instrument between the acoustic beams

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B. L. Weber, D. B. Wuertz, D. C. Law, A. S. Frisch, and J. M. Brown

VOL. 9, NO. 3 JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY JUNE1992Effects of Small-Scale Vertical Motion on Radar Measurements of Wind and Temperature Profiles B. L. WEBER, D. B. WUERTZ, D. C. LAW,* A. S. I~RISCH, AND J. M. BROWN*Wave Propagation Laboratory, * Forecast Systems Laboratory, National Oceanic and Atmospheric Administration, U.S. Department of Comrnerce, Boulder, Colorado (Manuscript

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Ann E. Gargett

acoustic Doppler current profiler (ADCP), the Doppler turbulence (DOT) system described by Gargett (1994) . Velocities derived from a standard ADCP cannot be used to determine characteristics of the large eddies of turbulent flows because of spatial aliasing associated with the (depth dependent) spread of the slant beams. The vertical beam that differentiates DOT from standard Janus-configuration ADCPs provides unambiguous measurements of the vertical velocity component, which is most crucial to

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