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Ronald W. Fegley
,
Howard T. Ellis
, and
J. L. Heffter

calculations suggested that the source was Nyiragongovolcano in central Africa (1.5-S, 29.2-E). The presence of an adiabatic temperature profile through thedust layer suggests that the volcanic layer was being convected by means of radiative absorption. Thismechanism may provide sulfate for the maintenance of a background level of stratospheric sulfate.During the six years of lidar observations in Hawaii (19.5-N), we have rarely observed such layers.Visual, lidar and other observations of the volcanic

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V. E. Derr
,
N. L. Abshire
,
R. E. Cupp
, and
G. T. McNice

insufficient to precisely account for this experimental result,but is shown possible in principle by Liou and Lahore(1974). Depoarization by multiple scatter may occur indense water clouds. It is a function of optical depth,the phase function, and receiver beamwidth. It canapproach depolarization values found in ice cloudswithout multiple scatter (Werner, 1974). It will be seenthat it is not important in the observation presentedhere.3. Observation Lidar observations of virga were made at Boulder

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J. D. Spinhirne
,
M. Z. Hansen
, and
J. Simpson

lidaroperated from a high altitude aircraft. Case studies of measurements acquired from cumuliform cloud systemsare presented, two from September 1979 observations in the area of Florida and adjacent waters and a thirdduring the May 1981 CCOPE experiment in southeast Montana. Accurate cloud top height structure andrelative density of hydrometers are obtained from the lidar return signal intensity. Correlation between thesignal return intensity and active updrafts was noted. Thin cirrus overlying developing

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R. Boers
,
H. Russchenberg
,
J. Erkelens
,
V. Venema
,
A. van Lammeren
,
A. Apituley
, and
S. Jongen

the next range point on the lidar signal profile. After this first regression the new cloud base value is now located between two points on the original extinction profiles separated by 30 m. The new value for z B is used to update D using Eq. (4) while leaving LWP constant. Using the new value of D, which is typically between 0.01 and 0.07 different from the original value, a final regression of the theoretical extinction curve to the observations is performed as a second step. Excellent

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R. L. Schwiesow
,
S. D. Mayor
,
V. M. Glover
, and
D. H. Lenschow

System (NAILS) observed the edge of an extended, sloping aerosol layerthat intersected a stratocumulus cloud deck over the Pacific Ocean during the First ISCCP (International SatelliteCloud Climatology Project) Regional Experiment, 260 km WNW of San Diego. In situ measurements supportthe interpretation of the lidar observations as arising from a particle-laden layer with relatively clean air above,below, and to the SW. Intersection of tbese sloping layers with cloud top leads to substantial

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Kenneth Sassen

568JOURNAL OF CLIMATE AND APPLIED. METEOROLOGYVOLUME 23Deep Orographic Cloud Structure and Composition Derived fromComprehensive Remote Sensing MeasurementsKENNETH SASSENDepartment of Meteorology, University of Utah, Salt Lake City, UT 84112(Manuscript received 18 July 1983, in final form 20 January 1984)ABSTRACTCoordinated polarization lidar, K.,-band radar and dual-channel microwave radiometer observations of adeep orographic cloud system were collected from a mountain-base site in

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Plamen B. Savov
,
Toni S. Skakalova
,
Ivan N. Kolev
, and
Francis L. Ludwig

formation and destruction all determine the temporal and spatial distribution of the aerosol pollutants in the valley atmosphere. All these factors are strongly affected by the valley configuration. Mountain-valley circulations often recirculate pollution from industrial sources. It is obviously important that the above processes be understood. Prior to this study, Collis (1968) had made some of the earliest lidar observations of the atmospheric properties over forested valleys. Other early studies of

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Yuying Zhang
and
Gerald G. Mace

equivalent the Cloud Profiling Lidar (CPL; McGill et al. 2004 ). The ACR, CPL, and MAS have flown on the NASA ER-2 in several recent field programs, and the CloudSat, CALIPSO, and Aqua satellites will fly in close formation so that their footprints will overlap spatially and will very nearly overlap temporally. In this paper, section 2 describes the physical background of the observations, the simplifying assumptions we use to derive the forward-model equations, and the mathematical framework we use

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J.-P. Vernier
,
T. D. Fairlie
,
J. J. Murray
,
A. Tupper
,
C. Trepte
,
D. Winker
,
J. Pelon
,
A. Garnier
,
J. Jumelet
,
M. Pavolonis
,
A. H. Omar
, and
K. A. Powell

airspace between 20 and 24 June 2011. In section 4 , we validate the analyses using independent daytime CALIPSO observations of volcanic ash, which were excluded from the trajectory mapping. In section 5 , we discuss the advantages and limitations of the system and its potential to improve aviation safety during future volcanic events. 2. CALIPSO detection of volcanic ash clouds The primary instruments on the CALIPSO payload are the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP), which

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Magdalena Rucker
,
Robert M. Banta
, and
Douw G. Steyn

Kali Gandaki Valley ( Egger et al. 2000 ). In this contribution, we investigate the along-valley structure of daytime flows in the Wipp Valley, Austria, using high-resolution Doppler lidar observations. These measurements, which also show along-valley volume flux divergence, were obtained in fall 1999 as part of the Mesoscale Alpine Program (MAP) field campaign ( Bougeault et al. 2001 ). Although the MAP–Wipp Valley field work focused on foehn and gap flow events, a sequence of fine weather days

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