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RACORO Continental Boundary Layer Cloud Investigations: 1. Case Study Development and Ensemble Large-Scale ForcingsObservation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60 h case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in situ measurements from the Routine AAF (Atmospheric Radiation Measurement (ARM) Aerial Facility) CLOWD (Clouds with Low Optical Water Depth) Optical Radiative Observations (RACORO) field campaign and remote sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functions for concise representation in models. Values of the aerosol hygroscopicity parameter, kappa, are derived from observations to be approximately 0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing data sets are derived from the ARM variational analysis, European Centre for Medium-Range Weather Forecasts, and a multiscale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in "trial" large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.
Document ID
20160003596
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Vogelmann, Andrew M. (Brookhaven National Lab. Upton, NY, United States)
Fridlind, Ann M. (NASA Goddard Inst. for Space Studies New York, NY United States)
Toto, Tami (Brookhaven National Lab. Upton, NY, United States)
Endo, Satoshi (Brookhaven National Lab. Upton, NY, United States)
Lin, Wuyin (Brookhaven National Lab. Upton, NY, United States)
Wang, Jian (Brookhaven National Lab. Upton, NY, United States)
Feng, Sha (California Univ. Los Angeles, CA, United States)
Zhang, Yunyan (Lawrence Livermore National Lab. Livermore, CA, United States)
Turner, David D. (National Oceanic and Atmospheric Administration Highlands, NJ, United States)
Liu, Yangang (Brookhaven National Lab. Upton, NY, United States)
Li, Zhijin (California Univ. Los Angeles, CA, United States)
Xie, Shaocheng (Lawrence Livermore National Lab. Livermore, CA, United States)
Ackerman, Andrew S. (NASA Goddard Inst. for Space Studies New York, NY United States)
Zhang, Minghua (Stony Brook Univ. Stony Brook, NY, United States)
Khairoutdinov, Marat (Stony Brook Univ. Stony Brook, NY, United States)
Date Acquired
March 22, 2016
Publication Date
June 27, 2015
Publication Information
Publication: Journal of Geophysical Research: Atmospheres
Volume: 120
Issue: 12
ISSN: 2169-8996
Subject Category
Meteorology and Climatology
Report/Patent Number
GSFC-E-DAA-TN30575
Funding Number(s)
WBS: WBS 281945.02.20.02.37
Distribution Limits
Public
Copyright
Other
Keywords
Boundary layers
Cloud physics
Aerosols
Large eddy simulation