Search Results

You are looking at 41 - 50 of 521 items for :

  • Lidar observations x
  • Monthly Weather Review x
  • Refine by Access: All Content x
Clear All
Jason A. Otkin, Daniel C. Hartung, David D. Turner, Ralph A. Petersen, Wayne F. Feltz, and Erik Janzon

periods with little manual intervention. Profile observations were created to emulate the Doppler wind lidar (DWL), microwave radiometer (MWR), and Atmospheric Emitted Radiance Interferometer (AERI) sensors. Observations were also created to emulate the state-of-the-art Raman lidar (RAM) system run operationally at the Department of Energy’s Atmospheric Radiation Measurement (ARM) site in north-central Oklahoma ( Goldsmith et al. 1998 ; Turner et al. 2000 , 2002 ); however, this sensor is currently

Full access
David B. Parsons, Melvyn A. Shapiro, R. Michael Hardesty, Robert J. Zamora, and Janet M. Intrieri

obtained from the Doppler lidar measurementswere combined with the equations of motion to derive perturbation fields of pressure and virtual potentialtemperature By. Our observations indicate that the circulations associated with this retrogressing dryline weredominated by hot, dry air riding over a westward moving denser, moist flow in a manner similar to a densitycurrent. Gravity waves were observed above the dryline interface. Previous observational and numerical studieshave shown that differential

Full access
Ali Behrangi, Terry Kubar, and Bjorn Lambrigtsen

launch and operation of the millimeter-wavelength cloud-profiling radar (CPR) ( Im et al. 2005 ) on CloudSat ( Stephens et al. 2002 ) and the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) ( Winker et al. 2007 ) on Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations ( CALIPSO ) occurred in late April 2006, and has offered unprecedented opportunities for global studies of hydrometeors and the vertical structure of cloud systems. CloudSat and CALIPSO are part of the A

Full access
David O'C. Starr, C. Laurence Korb, Geary K. Schwemmer, and Chi Y. Weng

June 1991, in final form 29 April 1992) Airborne observations using a downward-looking, dual-frequency, near-infrared, differential absorption lidar(DIAL) system provide the first measurements of the height-dependent pressure-perturbation field associatedwith a strong mesoscale gravity wave. A pressure-perturbation amplitude of 3.5 mb was measured within thelowest 1.6 km of the atmosphere over a 52.kin flight line. Corresponding vertical displacements of 250-500 mwere inferred from lidar

Full access
C. J. Grund and E. W. Eloranta

-zenith observations. Correlations between small-scale wind structure andcirrus cloud morphology have been observed. These correlations can bias the range averaging inherent in windpwfding lidars of modest vertical resolution, leading to increased measurement errors at drrus altitudes. Extendedperiods of low intensity hackscatter were noted between more strongly organized cirrus cloud activity. Opticalthicknesse/ranging from 0.01-1.4, backscatter-phase functions between 0.02-0.065 sr-~, and backscatter

Full access
Shane D. Mayor, Gregory J. Tripoli, and Edwin W. Eloranta

lidar data to monitor the evolution of convective structures in a convective boundary layer. Avissar et al. (1998) compared autocorrelation functions of lidar backscatter with simulated aerosol scattering in an LES of a homogeneous convective boundary layer. Therefore, this paper builds upon the previous research and demonstrates how techniques that use aerosol backscatter data can be applied to the testing of LESs of inhomogeneous convective boundary layers. 2. Lidar observations The University

Full access
B. B. Demoz, D. O’C. Starr, K. D. Evans, A. R. Lare, D. N. Whiteman, G. Schwemmer, R. A. Ferrare, J. E. M. Goldsmith, and S. E. Bisson

activity during a dryline–frontal merger ( Shapiro et al. 1985 ; Parsons et al. 2000 ). In addition, it is the only lidar-based observational study that clearly illustrates the time–height evolution of the interaction between a dryline, undular bore, and a cold front. This paper focuses only on the observations; numerical simulations and wavelet-based-analysis aspects of the data will follow in a subsequent work. Section 2 describes the synoptic conditions, time series surface mesonet observations

Full access
Robert M. Banta

California, or perhaps even a largercontinental scale. The lidar observations also included the evening transition, which began as a very shallowland breeze observed only by surface observing stations. In the deep sea-breeze layer between 250 m and 1 kmAGL, the flow returned to offshore gradient flow simultaneously through the entire layer 2-4 h after sunset.The sea breeze was thus seen as a daytime interruption of the basic gradient offshore flow.1. Introduction Sea breezes occurring on two different

Full access
Daniel C. Hartung, Jason A. Otkin, Ralph A. Petersen, David D. Turner, and Wayne F. Feltz

Raman lidar is evident ( Figs. 4a–d ). Contrary to the positive impacts on the thermodynamic fields, assimilation of RAM profiles alone degraded the vector wind analysis below 400 hPa in the CONV-RAM case ( Figs. 4e,f ). Minor differences exist below 400 hPa between cases in which DWL wind observations are assimilated, supporting the conclusion from Part I that the improved wind accuracy relative to the CONV case is due to the DWL wind observations. However, as an indirect affect on the wind field

Full access
David H. Levinson and Robert M. Banta

the ASCOTdomain. The NOAA/ERL Environmental Technology Laboratory Doppler lidar, one of an ensemble of instrumentsparticipating in the ASCOT field experiment, obtained high-resolution measurements of the structure of boththe vortex and the canyon drainage flows. The lidar observations documented the kinematic and structuralchanges in the cyclone and their relationship to a drainage jet exiting a nearby canyon. Lidar analyses clearlyshow the layering and stratification present during this case

Full access