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temporal behavior of the SBI layer, Wi-BLEx observational data from a winter period of collocated radiosonde–acoustic sounding observations at the NWS PAFA station are provided. The high-resolution profiling of the ABL structure is displayed in this section to illustrate the fact that low-level inversions are effectively present at the levels at which the radiosonde retrieves them, consistently throughout the entire measurement period. In this case the selected period was 11–13 January 2010. The flow
temporal behavior of the SBI layer, Wi-BLEx observational data from a winter period of collocated radiosonde–acoustic sounding observations at the NWS PAFA station are provided. The high-resolution profiling of the ABL structure is displayed in this section to illustrate the fact that low-level inversions are effectively present at the levels at which the radiosonde retrieves them, consistently throughout the entire measurement period. In this case the selected period was 11–13 January 2010. The flow
additional site-9 instrumentation was provided by the U.S. Army Research Office under DURIP Grant W911NF-10-1-0238, and we are grateful to Dr. Walter Bach for his interest and support. Glenn Hunter of PSU assisted with WRF data processing; Dr. Kenneth Underwood and Mr. Josh Underwood at Atmospheric Systems Corporation provided sodar installation services, maintenance assistance, and knowledge of sodar operating principles; and Dr. Dennis Thomson lent helpful insight on acoustic measurements of the
additional site-9 instrumentation was provided by the U.S. Army Research Office under DURIP Grant W911NF-10-1-0238, and we are grateful to Dr. Walter Bach for his interest and support. Glenn Hunter of PSU assisted with WRF data processing; Dr. Kenneth Underwood and Mr. Josh Underwood at Atmospheric Systems Corporation provided sodar installation services, maintenance assistance, and knowledge of sodar operating principles; and Dr. Dennis Thomson lent helpful insight on acoustic measurements of the
nighttime vertical profiles of potential temperature and wind velocity. Near-target remote sensing measurement techniques such as integrated sound detection and ranging (sodar) and radio acoustic sounding system (RASS) systems are able to measure vertical profiles of temperature and wind velocity, which can be used to determine the boundary layer height and its stability at high temporal resolution. However, it is challenging to reduce the wealth of data to characterize the long-term behavior of the
nighttime vertical profiles of potential temperature and wind velocity. Near-target remote sensing measurement techniques such as integrated sound detection and ranging (sodar) and radio acoustic sounding system (RASS) systems are able to measure vertical profiles of temperature and wind velocity, which can be used to determine the boundary layer height and its stability at high temporal resolution. However, it is challenging to reduce the wealth of data to characterize the long-term behavior of the
in the ABL ( Kallistratova 1994 ; Emeis et al. 2007 ). Sodar-derived vertical velocities also provide a measure of convection intensity. For urban measurements, sodar has advantages over radar and lidar wind profilers. Unlike radar, it is not necessary to allocate an electromagnetic band for sodar, and relative to low-power lidar a sodar has a greater height range (higher-power lidar has greater range but requires further governmental approval). Moreover, the cost of a sodar unit is typically
in the ABL ( Kallistratova 1994 ; Emeis et al. 2007 ). Sodar-derived vertical velocities also provide a measure of convection intensity. For urban measurements, sodar has advantages over radar and lidar wind profilers. Unlike radar, it is not necessary to allocate an electromagnetic band for sodar, and relative to low-power lidar a sodar has a greater height range (higher-power lidar has greater range but requires further governmental approval). Moreover, the cost of a sodar unit is typically
Acoustic Doppler Measurement of Atmospheric Boundary LayerVelocity Structure Functions and Energy Dissipation Rates J. E. GA~o~Wa~e Propagation Laboratory, NOAA Environmental Re. search Laboratory, Bo~, Colo. ~0302(M~u~fipt received 2 April 1976, in revised form 24 J~ua~ 1977) ABSTRACT Acoustic echo sounder (echosonde) and meteorological tower measurements of the turbulent velocitystructure parameters D(r) and C~ and the rate of dissipation of turbulent
Acoustic Doppler Measurement of Atmospheric Boundary LayerVelocity Structure Functions and Energy Dissipation Rates J. E. GA~o~Wa~e Propagation Laboratory, NOAA Environmental Re. search Laboratory, Bo~, Colo. ~0302(M~u~fipt received 2 April 1976, in revised form 24 J~ua~ 1977) ABSTRACT Acoustic echo sounder (echosonde) and meteorological tower measurements of the turbulent velocitystructure parameters D(r) and C~ and the rate of dissipation of turbulent
-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
-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
)ABSTRACT A field method of estimating the persistence of a commonly used silver iodide seeding agent is described.The method involved measurement of the AgI plume structure at two downwind distances from the groundgenerator(s). Distances between the nine available pairs of downwind measurement planes ranged fromapproximately I0 to 100 kin. An NCAR acoustical ice nucleus counter in a light twin aircraft was used tosample the AgI plumes. A series of passes was made through the entire vertical and
)ABSTRACT A field method of estimating the persistence of a commonly used silver iodide seeding agent is described.The method involved measurement of the AgI plume structure at two downwind distances from the groundgenerator(s). Distances between the nine available pairs of downwind measurement planes ranged fromapproximately I0 to 100 kin. An NCAR acoustical ice nucleus counter in a light twin aircraft was used tosample the AgI plumes. A series of passes was made through the entire vertical and
mow, of those from atmospheric thermal turbulenceand of the acoustic noise background. On the basis of the demonstrated statistical behavior of echo sounder signals, a procedure is describedfor the estimation from digitized data of this kind of mean-scattering cro~s sections and mean velocitiesof turbulent air parcels, and for the suppression of the effects of background noise.1. Introduction The frequency of sound waves scattered from atmospheric turbulence is changed by an amount relatedto
mow, of those from atmospheric thermal turbulenceand of the acoustic noise background. On the basis of the demonstrated statistical behavior of echo sounder signals, a procedure is describedfor the estimation from digitized data of this kind of mean-scattering cro~s sections and mean velocitiesof turbulent air parcels, and for the suppression of the effects of background noise.1. Introduction The frequency of sound waves scattered from atmospheric turbulence is changed by an amount relatedto
have been constructed that effectively reject noise interference, and the corresponding detectlon logic has been developed that identifies the wind velocity from the processed signal. Recent testsemployed an acoustic radar to measure the wind velocity in close prox/mity to conventlon~l anemometer andvane instrumentation. Comparison between the measurements from the two sensors shows a high degree ofcorrelation; the observed differences are also discussed.1. Background Measurement of wind speed
have been constructed that effectively reject noise interference, and the corresponding detectlon logic has been developed that identifies the wind velocity from the processed signal. Recent testsemployed an acoustic radar to measure the wind velocity in close prox/mity to conventlon~l anemometer andvane instrumentation. Comparison between the measurements from the two sensors shows a high degree ofcorrelation; the observed differences are also discussed.1. Background Measurement of wind speed
the speed at which the acousticdisturbance propagates. Recently, the Aeronomy Laboratory has devised several enhancements to RASS(Angevine et al. 1993). The most important of theseis the ability to measure the acoustic velocity and thewind velocity simultaneously. This is key to the heatflux measurement. The radar is set to cycle through four or five differentbeam directions in sequence. Four of the beam positions are separated by 90- in azimuth (in this case thefour cardinal directions are
the speed at which the acousticdisturbance propagates. Recently, the Aeronomy Laboratory has devised several enhancements to RASS(Angevine et al. 1993). The most important of theseis the ability to measure the acoustic velocity and thewind velocity simultaneously. This is key to the heatflux measurement. The radar is set to cycle through four or five differentbeam directions in sequence. Four of the beam positions are separated by 90- in azimuth (in this case thefour cardinal directions are
