Search Results

You are looking at 1 - 10 of 900 items for :

  • Lidar observations x
  • Journal of the Atmospheric Sciences x
  • All content x
Clear All
Katrina S. Virts, John M. Wallace, Qiang Fu, and Thomas P. Ackerman

–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, launched in 2006, carries a two-wavelength polarization lidar, the first space-based lidar optimized for cloud and aerosol layer detection. This instrument is capable of detecting subvisible cirrus layers with optical depths of 0.01 or less ( Winker et al. 2007 ). Two contrasting formation mechanisms for TTL cirrus have been advanced in the literature: Detrainment: Outflow from the anvil region of deep convective clouds has

Full access
Steven Beck, David Stoker, James Hecht, and Richard Walterscheid

, and vertical structure. Temperature profiles and wind data were obtained for the lidar operational period from the Aircraft Communication Addressing and Reporting System (ACARS) of commercial aircraft data. Profiles obtained for aircraft departing and arriving at Los Angeles International Airport (LAX) were selected for temporal and spatial coincidence with the lidar observations. In addition, satellite images of the smoke distribution over the basin were obtained from Moderate Resolution Imaging

Full access
Irina Strelnikova, Marwa Almowafy, Gerd Baumgarten, Kathrin Baumgarten, Manfred Ern, Michael Gerding, and Franz-Josef Lübken

. 2010 ; Ern et al. 2018 ). On the other hand, different instruments covering different spectral windows of the GW spectrum yield complementary observations. The combination of different instruments, e.g., lidar and satellite, usually provide a more detailed picture of GW parameters ( Llamedo et al. 2019 ). In practice, it is often convenient to have an average reference GW field being representative for a certain latitude and season. Such averaged GW fields, also called climatologies, were

Open access
Vincent Noel, Helene Chepfer, Martial Haeffelin, and Yohann Morille

crystals in ice clouds, as their infinite variety makes this an unrealistic goal. Instead, the depolarization ratio is used to classify particles in a given cloud area into three distinct groups: platelike, columnlike, and irregular shapes. It is important to note that platelike and columnlike refer to particles that scatter light respectively like plates (including aggregates of plates) or columns (including aggregate of columns and bullet rosettes). As lidar observations are vertically resolved, the

Full access
Michael Hill, Ron Calhoun, H. J. S. Fernando, Andreas Wieser, Andreas Dörnbrack, Martin Weissmann, Georg Mayr, and Robert Newsom

larger-scale flows in the lee of mountains ( Doyle and Durran 2007 ). These simulations are helping to illuminate the importance of surface friction in rotor development by showing, for example, that rotors can fail to develop, even in instances of high shear, if the atmospheric state is unfavorable for lee wave formation. In this paper, we show that two coherent Doppler lidar scanning the same vertical–horizontal plane can provide direct observational evidence showing the spatial extent, strength

Full access
Katrina S. Virts and John M. Wallace

1. Introduction In the companion paper ( Virts et al. 2010 ; hereafter, VWFA ), we introduce an analysis protocol for relating features in the frequency of occurrence of cirrus clouds in the tropical tropopause transition layer (TTL), as observed by the polar-orbiting Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), to fields of atmospheric variables throughout the tropics. The protocol involves the generation of a TTL cirrus index (cloud fraction; i.e., the

Full access
Gijs de Boer, Edwin W. Eloranta, and Matthew D. Shupe

tens of meters thick and the thickest around 1000 m thick on average. The thickest clouds exist during fall and the thinnest during spring. Barrow observations show substantially thicker clouds, on average, than those observed in Eureka. Thirty-minute average lidar cloud optical depths are reviewed in Fig. 5d . These statistics are skewed by the AHSRL’s inability to penetrate deeper than an optical depth of around 5 before suffering from attenuation. As shown in Fig. 4 , a large fraction of these

Full access
Min Deng, Gerald G. Mace, Zhien Wang, J.-L. F. Li, and Yali Luo

that this result may not be exactly applicable to other datasets since the definition of lidar–radar regions depends on the sensitivities of instruments used in different projects. For the three-species ice-phase scheme in models, the cloud ice mass is generally contributed by the small particles, given the small size assumption of cloud ice. However, snow and graupel are not equivalent to the median and large modes in observations, respectively. Therefore, they need to be repartitioned with a

Full access
David Atlas, Bernard Walter, Shu-Hsien Chou, and P. J. Sheu

(Manuscript received 3 September 1985, in final form 29 January 1986)ABSTRACTThe combination of vertical lidar and in situ meteorological observations from two aircraft provide an unprecedented view of the marine atmospheric boundary layer (MABL) during a cold air outbreak. To a firstapproximation, the lidar reflectivity is associated with the concentration of sea salt aerosols. Across the cappinginversion, the lidar reflectivity contours approximate isentropes and streamlines thereby defining the

Full access
Timothy J. Beatty, Chris A. Hostetler, and Chester S. Gardner

15MARCH 1992 BEATTY ET AL. 477Lidar Observations of Gravity Waves and Their Spectra near the Mesopause and Stratopause at AreciboTIMOTHY J. BEATTY, CHRIS A. HOSTETLER, AND CHESTER S. GARDNERDepartment of Electrical & Computer Engineering, Everitt Laboratory, Urbana, Illinois(Manuscript received 31 May 1990, in final form 16 July 1991)ABSTRACT The UIUC CEDAR Rayleigh

Full access