Search Results

You are looking at 61 - 70 of 321 items for :

  • Planetary waves x
  • Journal of Atmospheric and Oceanic Technology x
  • All content x
Clear All
M. Portabella and A. Stoffelen

understanding of the unexplained year-to-year variability of these wind events. Wind information is available from conventional platform observations, such as ship or buoy. These systems measure the atmospheric flow at a measurement height that can vary between 4 and 60 m and, therefore, are not a direct measure of surface 10-m wind or of stress. Stress computation requires the transformation of these winds by planetary boundary layer (PBL) parameterization schemes to represent the sea surface conditions

Full access
Yoshiki Ito, Yasuhiro Kobori, Mitsuaki Horiguchi, Masato Takehisa, and Yasushi Mitsuta

follows. Phase shifted five-channel transmitting signals oscillated in the phase controller are provided to row orcolumn transducer elements, through power amplifiersand row/column gwitches. When transmitting signalswith phase lag of q are fed into transducer elements,the zenith angle 0 of steering beam is written as0 = sin-~(~o/2,r- x/d)(l)where X is the acoustic wave length and d is the distancebetween the centers of horns. The present system isable to generate phase shifted signals by ~r/8

Full access
Amin R. Nehrir, Kevin S. Repasky, and John L. Carlsten

housed on a 61 cm × 122 cm optical breadboard. A widely tunable external cavity diode laser (ECDL), based on a Littman–Metcalf configuration ( Nehrir et al. 2009 ), is capable of accessing the water vapor absorption band ranging from 824 to 841 nm is used as the seed source for the water vapor DIAL instrument. The output from a widely tunable ECDL in the Littman–Metcalf configuration has the narrow linewidth and broad tunability needed for the DIAL transmitter, but exhibits low continuous wave (cw

Full access
Wynn L. Eberhard, Richard E. Cupp, and Kathleen R. Healy

OCTOBER 1989 EBERHARD, CUPP AND HEALY 809Doppler Lidar Measurement of Profiles of Turbulence and Momentum Flux WYNN L. EBERHARD AND RICHARD E. CUPPNOAA /ERL Wave Propagation Laboratory, Boulder, Colorado KATHLEEN R. HEALYCIRES, University of Colorado, Boulder, Colorado(Manuscript received 14 September 1988, in final form 22 March 1989)ABSTRACT A short-pulse CO2 Doppler lidar with 150-m range

Full access
Vladimir N. Kapustin, Antony D. Clarke, Steven G. Howell, Cameron S. McNaughton, Vera L. Brekhovskikh, and Jingchuan Zhou

1. Introduction In the remote marine atmosphere there are four principal sources of natural aerosols. Sea salt aerosol (SSA) production by wind and breaking waves is the dominant source of primary aerosol mass ( Lewis and Schwartz 2004 ). In situ atmospheric oxidation of reduced sulfur derived from marine dimethyl sulfide (DMS) emission is another source of marine boundary layer (MBL) aerosol ( Clarke et al. 1998b ; Kulmala et al. 2004 ). Entrainment of aerosol from the free troposphere in

Full access
Kyoung-Ho Cho, Yan Li, Hui Wang, Kwang-Soon Park, Jin-Yong Choi, Kwang-Il Shin, and Jae-Il Kwon

rescue The leeway model, developed by the Norwegian Meteorological Institute ( Hackett et al. 2006 ), is adopted for search and rescue modeling. Assuming a linear relationship between wind speed and the leeway of a floating object and ignoring wave effects, the trajectory model calculates the arc traced by the superposition of the leeway vector and the surface current vector as follows ( Breivik and Allen 2008 ): where x 0 is the initial position of the object, x ( T ) is the position at time T

Full access
Igor Smalikho

model described by Eq. (2) . The wind vector estimate V̂ is obtained by the fitting of the radial velocities V̂ ri to the theoretical dependence of the radial wind velocity versus the azimuth angle θ i [ Eq. (3) ]. Such a procedure is called the sine wave fitting (SWF), because V ri ≡ V r ( θ i ) = V z sin ϕ + U cos ϕ sin( θ i − θ V + π /2), where U = V 2 x + V 2 y is the horizontal wind velocity and θ V = arg( V x + jV y ) is the angle of the wind direction ( Lhermitte

Full access
J. M. White, J. F. Bowers, S. R. Hanna, and J. K. Lundquist

1. Background and objectives Nearly all atmospheric transport and dispersion (ATD) models make use of inputs of the mixing depth, also known as the mixing height or the planetary boundary layer height ( Arya 1999 ). The mixing depth defines the top of the layer near the surface where turbulent mixing is occurring. During the daytime, the mixed layer typically has an adiabatic or superadiabatic temperature lapse rate and the mixing depth is often marked by a capping inversion. During sunny

Full access
Ulrich Görsdorf and Volker Lehmann

1. Introduction The Radio Acoustic Sounding System (RASS) is a useful device for remote sensing of vertical temperature profiles with high temporal resolution in the lower troposphere. Most frequently, a so-called BRAGG–RASS ( Peters et al. 1983 ) is integrated in wind profiler radars (WPRs), where the sound velocity is determined from the acoustic frequency that fulfills the Bragg condition (the acoustic wave number k a is equal to twice of the electromagnetic wavenumber k e ). Although the

Full access
Markus Furger, Philippe Drobinski, AndréS. H. Prévôt, Rudolf O. Weber, Werner K. Graber, and Bruno Neininger

measurements during a severe downslope windstorm, when significant wave activity and turbulence occurs in mountainous terrain ( Brinkmann 1971 ; Hoinka 1985 ; Seibert 1990 ). Under such conditions, unusually strong vertical components show up in the measurements. An estimate of the accuracy of the vertical crosswind velocity measurement is prerequisite for further use of the data, for example, for calculations of turbulent kinetic energy or momentum fluxes. The observed high crosswind velocities led to

Full access