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Natalie Midzak, John E. Yorks, Jianglong Zhang, Bastiaan van Diedenhoven, Sarah Woods, and Matthew McGill

derived from airborne polarimeter observations. However, only broad plate-like or column-like categories can be derived using polarimeter observations alone. Noel et al. (2004) found lidar depolarization ratio to be sensitive to modeled aspect ratio which allowed for a coarse classification of habit types. Still only broad ice crystal categories including plates or spheroids, irregulars and columns were derived from the study. Also, distinguishing small from large ice crystals is a challenging task

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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

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Minttu Tuononen, Ewan J. O’Connor, Victoria A. Sinclair, and Ville Vakkari

observations at Cabauw in the Netherlands. Sodar data have also been used to determine the occurrence and characteristics of LLJs—for example, in Florida ( Karipot et al. 2009 ) and in Moscow ( Kallistratova and Kouznetsov 2012 ). High-resolution Doppler lidar has proven to be an ideal instrument to measure vertical wind profiles ( Banta et al. 2002 , 2013 ), and Doppler lidar systems have even been deployed on ships ( Tucker et al. 2010 ; Pichugina et al. 2012 ), enabling the investigation of LLJs in

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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

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H. Luce, T. Takai, T. Nakamura, M. Yamamoto, and S. Fukao

acquisition time and the radar resolution volume. Its range resolution (typically 150 m or more) is a limitation because the humidity (and temperature) gradients are frequently shallower. Obviously, colocalized and continuous observations of humidity would more properly help to validate the radar technique approach. This can be achieved from colocalized Raman lidar observations ( Imura et al. 2007 ). Lidar observations can be performed continuously during favorable conditions (clear nights). Humidity is

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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

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Christian Kühnlein, Andreas Dörnbrack, and Martin Weissmann

strong and possibly severe turbulence. However, as already pictured by Förchgott (1949) and impressively shown by Hertenstein and Kuettner (2005) using numerical simulations, a variation of the upstream shear at mountaintop level results in a totally different downslope flow and rotor types. Moreover, observations of downslope flows and rotors revealing the spatial structure in the boundary layer and the temporal evolution were missing. Some ground-based coherent Doppler lidar observations were

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Stuart A. Young, Mark A. Vaughan, Ralph E. Kuehn, and David M. Winker

1. Introduction The Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations ( CALIPSO ) satellite began acquiring scientific data in mid-June 2006. CALIPSO carries three coaligned, nadir-viewing instruments: a three-channel elastic-backscatter lidar, an imaging infrared radiometer, and a wide-field camera. An overview of the CALIPSO mission, science objectives, and instruments is presented in Winker et al. (2010) . The CALIPSO lidar [Cloud–Aerosol Lidar with Orthogonal

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Brian J. Carroll, Belay B. Demoz, David D. Turner, and Ruben Delgado

reanalysis datasets reveal the LLJ patterns already discussed but are limited in their ability to resolve some important details of the spatiotemporal evolution of the LLJ throughout its domain (e.g., Whiteman et al. 1997 ; Song et al. 2005 ; Walters et al. 2008 , 2014 ). Targeted observations have been utilized over the years to improve our understanding of LLJs, MCSs, NCI, and their interplay. Wind, water vapor, and elastic backscatter lidars have been some of the key tools in these advanced

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Michael Bennett, Simon Christie, Angus Graham, and David Raper

field trials at Heathrow and Manchester airports using a rapid-scanning lidar in conjunction with various other observations. This paper describes the field work undertaken and how we have elaborated the hardware and software of the lidar system so that it should be capable of monitoring aviation emissions. We illustrate this capability with images of dispersing aircraft plumes under a range of operational modes. Subsequent papers ( Bennett and Christie 2010 ; A. Graham et al. 2010, unpublished

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