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Bart Geerts, David Parsons, Conrad L. Ziegler, Tammy M. Weckwerth, Michael I. Biggerstaff, Richard D. Clark, Michael C. Coniglio, Belay B. Demoz, Richard A. Ferrare, William A. Gallus Jr., Kevin Haghi, John M. Hanesiak, Petra M. Klein, Kevin R. Knupp, Karen Kosiba, Greg M. McFarquhar, James A. Moore, Amin R. Nehrir, Matthew D. Parker, James O. Pinto, Robert M. Rauber, Russ S. Schumacher, David D. Turner, Qing Wang, Xuguang Wang, Zhien Wang, and Joshua Wurman

, 406 – 419 , doi: 10.1175/1520-0493(1975)103<0406:DVIPAT>2.0.CO;2 . 10.1175/1520-0493(1975)103<0406:DVIPAT>2.0.CO;2 Wang , Z. , and Coauthors , 2011 : Observations of boundary layer water vapor and aerosol structures with a compact airborne Raman lidar. Fifth Symp. on Lidar Atmospheric Applications , Seattle, WA, Amer. Meteor. Soc., 3.6. [Available online at .] Weckwerth , and Coauthors , 2004 : An overview of the

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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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Joshua G. Gebauer, Alan Shapiro, Evgeni Fedorovich, and Petra Klein

to other no-boundary CI events. These three events were examined in the present study to determine the role of the LLJ in initiating the nocturnal CI. Unfortunately, the three CI events considered in this study occurred on nights during which there was either no PECAN intensive operation period (IOP) or the PECAN IOP was focused on a region away from the CI. Since the mobile platforms were not positioned to observe these CI episodes, the best available observations were provided by the fixed

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W. G. Blumberg, T. J. Wagner, D. D. Turner, and J. Correia Jr.

latest version, AERIoe, version 2.2, surface layer observations and observations from additional sources of upper-air thermodynamic profiles (e.g., radiosondes, NWP forecast soundings, Raman lidar) can be included within Y . The inclusion of NWP forecast soundings in the mid- to upper troposphere improves the overall retrieval as short-term forecast models are often most accurate at these altitudes ( Thompson et al. 2003 ; Benjamin et al. 2004a , b ). The intent of including these observations in

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David B. Parsons, Kevin R. Haghi, Kelton T. Halbert, Blake Elmer, and Junhong Wang

dynamical relationship among density currents, bores, and the nocturnal environment utilizing observations taken during the International H 2 O Project (IHOP_2002; Weckwerth et al. 2004 ). Through an application of a variant of hydraulic theory, Haghi et al. (2017) were able to show that as the night progressed, the interaction between convective outflows and the nocturnal environment tended to increasingly fall within a partially blocked flow regime where atmospheric bores would be generated. This

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Matthew D. Flournoy and Michael C. Coniglio

did enhance the near-surface wind speeds and backed the winds to a more southerly direction. This added to the already substantial low-level vertical wind shear in the simulated environment that was oriented nearly parallel to the gust front ( Fig. 13 ), which is consistent with observations from velocity–azimuth display wind retrievals from a Doppler wind lidar obtained in the region ahead of the main system in the enhanced southerly winds. Fig . 13. Evolution of both observed and simulated low

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Tammy M. Weckwerth, John Hanesiak, James W. Wilson, Stanley B. Trier, Samuel K. Degelia, William A. Gallus Jr., Rita D. Roberts, and Xuguang Wang

) suggested that an optimal combination of observations and assimilation of thermodynamic profiles is necessary for improved understanding of the planetary boundary layer. Developments of a small network of advanced differential absorption lidars (DIALs) to measure water vapor (e.g., Spuler et al. 2015 ; Weckwerth et al. 2016 ), calibrated aerosol ( Hayman and Spuler 2017 ) and temperature profiles ( Bunn et al. 2018 ) and the proposed Lower Troposphere Observing System (LOTOS) may aid in providing

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Shushi Zhang, David B. Parsons, and Yuan Wang

elevated layer can be neutral, as in many idealized studies, or weakly stable as is sometimes observed. 2. Observational analysis The MCS took place on 11–12 June 2015 during PECAN intensive observing period (IOP) 9. The surface observations at 2107 local standard time (LST) 11 June ( Fig. 2 ) depict a quasi-stationary front near where convection first formed. The front separated warm, moist air with temperatures generally exceeding ~28°C with dewpoints of ~19°C from cooler, drier air to the north. The

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Alan Shapiro, Evgeni Fedorovich, and Joshua G. Gebauer

Hays, KS. Among the observational platforms were research aircraft, the NCAR Earth Observing Laboratory (EOL) S-Pol Ka radar (S-Pol), mobile Doppler radars, Doppler lidars, Raman lidars, ceilometers, micropulse lidars (MPLs), water vapor differential absorption lidars (WV-DIALs), sodars, wind profilers, and radiosondes. Data were gathered in 31 Intensive Observing Periods (IOPs) and 12 Unofficial Field Operations (UFOs), 5 each with a focus on MCSs, bores, CI, or LLJs. Only seven IOPs were LLJ or

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