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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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Elizabeth N. Smith, Joshua G. Gebauer, Petra M. Klein, Evgeni Fedorovich, and Jeremy A. Gibbs

, and NLLJs. Primary data sources for NLLJ cases were the boundary layer profiles measured by mobile and fixed PECAN Integrated Sounding Arrays (PISAs). These datasets included profiles of dynamic and thermodynamic parameters obtained at high temporal and vertical resolution using Doppler lidars, Atmospheric Emitted Radiance Interferometers (AERIs), radar wind profilers, radiosondes, and microwave radiometers (MWRs), providing observations to describe the SBL and NLLJ evolution. There were four

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Coltin Grasmick, Bart Geerts, David D. Turner, Zhien Wang, and T. M. Weckwerth

lidars aboard the UWKA. These observations are used in an effort to understand the lifting mechanism and effective source level for CI in LC regions. Specifically, we use the airborne lidar data to determine the actual vertical displacement for parcels at all possible source levels and compare this against the vertical distance to the parcel’s LFC. The UWKA completed a total of 20 transects across three convergent boundary zones leading this MCS. The first zone, referred to as Region I ( Fig. 2 ), is

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Dana Mueller, Bart Geerts, Zhien Wang, Min Deng, and Coltin Grasmick

associated with a nocturnal MCS. This observational case study is unique in that it explores the evolution of the vertical structure of a bore. While other fixed, surface-based profiling observations depict a blend of distance and time evolution, this study uses airborne profiling lidar data, providing a series of quasi-instantaneous vertical transects, at a time resolution corresponding with the frequency of flight traverses across the bore (in this case 10–15 min). Another advantage to using an

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Samuel K. Degelia, Xuguang Wang, and David J. Stensrud

profilers similar to that recommended by the National Research Council (2009) . The observations assimilated here consist of atmospheric emitted radiance interferometers (AERIs; Turner and Löhnert 2014 ), Doppler wind lidars (e.g., Menzies and Hardesty 1989 ), radio wind profilers (e.g., Benjamin et al. 2004 ), high-frequency rawinsondes, and special surface data taken from fixed and mobile PECAN platforms. Assimilating similar datasets individually has been shown to improve convective

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J. W. Wilson, S. B. Trier, D. W. Reif, R. D. Roberts, and T. M. Weckwerth

parameters. The UWKA mostly flew at an elevation of roughly 2.15 km MSL. The primary leg of interest was flown from west to east between 0408 and 0432 UTC. Convection initiation occurred 25 km north of the track at 0405 UTC. Other flight legs helped identify the location of a wind-shift line to be discussed later. Particularly important were Doppler lidar observations from TWOLF and MP3 to help determine vertical wind profiles and cloud base and to detect atmospheric gravity waves. In addition, there was

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David M. Loveless, Timothy J. Wagner, David D. Turner, Steven A. Ackerman, and Wayne F. Feltz

bores will change their characteristics over the course of their lifetimes. Koch et al. (2008) used a combination of observations and numerical simulations to identify changes in the turbulent nature of the bore over the course of its life cycle. They identified that the majority of turbulent kinetic energy is generated by the shear stress from the strong along-bore flow associated with the low-level jet (LLJ). Additionally, they found that early in the life cycle of the bore, in what they called

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Aaron Johnson, Xuguang Wang, Kevin R. Haghi, and David B. Parsons

from nocturnal radiative cooling. Undulations in the potential temperature contours were observed after the cooling aloft, consistent with the passage of the undular bore. Both the undulations and lifting of potential temperature contours were consistent with the vertical velocity observations described above. In the DC8 DIAL and UWKA Raman lidar retrievals ( Figs. 5d–h ), abrupt moistening aloft was also consistent with the mean layer lifting resulting from bore passage and was therefore also used

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Aaron Johnson and Xuguang Wang

Convection at Night (PECAN) field experiment took place in 2015 with the purpose of collecting comprehensive and targeted observations of bores and other phenomena related to nocturnal convection ( Geerts et al. 2017 ). One use of these unprecedented observations is the ability to validate the details of model simulated bores to better understand the sensitivities and sources of error in numerical weather prediction (NWP) involving bores. For example, Johnson et al. (2018) used data from the 11 July

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Samuel K. Degelia, Xuguang Wang, David J. Stensrud, and Aaron Johnson

PECAN will provide dense datasets for verifying the mechanisms responsible for convection at night. As nocturnal convection is often elevated and initiated by features located above the surface, the assimilation of unique thermodynamic and kinematic observations collected during PECAN (e.g., radiometers, Doppler lidars, and wind profilers) can also provide key information for estimating such environments. Future work will examine the impact of assimilating these unique observation sets. Since

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