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L. P. Riishøjgaard
,
R. Atlas
, and
G. D. Emmitt

remains a high priority for the global observing system. Such observations are expected to be especially valuable in situations in which the balance assumptions used for assimilation of satellite sounding data are invalid and in regions where the geostationary wind observations are either poor or missing altogether. A spaceborne Doppler wind lidar (DWL) is one of the candidate systems for providing these data. The measurement principle is based on the fact that the Doppler shift of the return from an

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N. L. Abshire
,
R. L. Schwiesow
, and
V. E. Derr

DECEMBEaI974 NOTES AND CORRESPONDENCE 951 Doppler Lidar Observations of Hydrometeors N. L. ABSItlRE, 1~. L. SCttWIESOW AND V. E. DERR En~ronmental Research -aboratories, NOAA, Boulder, Colo. 80302 6 November 1973 and 24 July 1974 ABSTRACT Significant Doppler lidar returns have been observed from snow and rain. This demonstrates the

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Volker Wulfmeyer
and
Tijana Janjić

because of their complex vertical variability. As a consequence, detailed clear-air observations of MBL variables are essential to improve modeling and simulation of transport processes and modeling and simulation of cloud and precipitation development. In recent years, considerable progress has been made in the development, improvement, and application of active remote sensing systems such as lidar for boundary layer research (e.g., Sullivan et al. 1998 ; Wulfmeyer 1999a , b ; Grund et al. 2001

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D. D. Turner

property retrieval algorithm (MIXCRA), which uses the physical iterative optimal estimation approach, was developed to retrieve cloud optical depth, ice fraction, liquid and ice water paths, and the effective radius of the water droplets and ice particles from single-layer optically thin clouds using data from ground-based AERI radiance and lidar cloud boundary observations. Simulated data and case studies were used to characterize this retrieval algorithm. The case studies demonstrated good agreement

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Tobias Marke
,
Susanne Crewell
,
Vera Schemann
,
Jan H. Schween
, and
Minttu Tuononen

meteorological-tower measurements ( Dörenkämper et al. 2015 ). Even though these observations provide good vertical resolution, they are lacking in temporal resolution (radiosondes) and vertical extent (towers). Therefore, many previous studies have utilized remotely sensing radio acoustic or (ultra–high frequency) radar wind profilers to obtain detailed case analyses and continuous long-term records of LLJs (e.g., Baas et al. 2009 ; Lampert et al. 2016 ; Mitchell et al. 1995 ). Doppler wind lidars (DWLs

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Andrew Heymsfield
,
Dave Winker
,
Melody Avery
,
Mark Vaughan
,
Glenn Diskin
,
Min Deng
,
Valentin Mitev
, and
Renaud Matthey

microphysical properties necessary to model accurately the radiative transfer in cloudy regions and to assess the role of clouds in climate. The National Aeronautics and Space Administration (NASA) A-Train constellation of satellites flying in formation includes two active cloud-profiling instruments. The Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations ( CALIPSO ) satellite is a nadir-viewing, polarization

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Chusei Fujiwara
,
Kazuya Yamashita
,
Mikio Nakanishi
, and
Yasushi Fujiyoshi

(e.g., Sinclair 1969 ). A number of invisible, intense, low-level vortices were detected by a research aircraft over boreal forests ( MacPherson and Betts 1997 ), however, suggesting that these phenomena may occur over various types of environments and a wide range of surface conditions ( Hess and Spillane 1990 ). For instance, in the urban area of Oklahoma City, some apparent vertical vortices can be found in the results of the Doppler lidar observations made by Newsom et al. (2005 , see their

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Donald E. Holland
,
Judith A. Berglund
,
Joseph P. Spruce
, and
Rodney D. McKellip

commonly used approaches to assigning Z 0 values are geometric models and micrometeorological observations. In an urban environment, geometric models require clear delineation of the surface obstacles (buildings and trees) that influence surface roughness. This paper describes a totally automated approach to the generation of Z 0 values from lidar terrain data that does not rely on any other data sources (e.g., aerial imagery or three-dimensional building datasets). Using only lidar data, this

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Andrew J. Heymsfield
,
Alain Protat
,
Dominique Bouniol
,
Richard T. Austin
,
Robin J. Hogan
,
Julien Delanoë
,
Hajime Okamoto
,
Kaori Sato
,
Gerd-Jan van Zadelhoff
,
David P. Donovan
, and
Zhien Wang

reflectivity measurements. They found that radar Z e -only approaches suffer from significant problems related to basic temperature-dependent cirrus cloud processes; however, excellent results were obtained when used with ancillary lidar or radiometric measurements. Mace et al. (2005) used a statistical approach to compare Moderate Resolution Imaging Spectroradiometer (MODIS) overpasses of cirrus with ground-based remote sensing observations. Using retrievals of cloud properties, it was found that there

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S. Pal
,
S. F. J. De Wekker
, and
G. D. Emmitt

z i based on only lidar-derived profiles of aerosol backscatter is considered to be an important future research task. Despite the challenges involved in comparing observations from a sensor launched from a particular place (radiosonde) with a moving platform (TODWL), we can conclude that TODWL- and radiosonde-derived z i are in reasonably good agreement, which confirms that high-resolution z i estimates using TODWL-derived backscatter profiles are appropriate for investigating z i

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