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Bruce Albrecht, Virendra Ghate, Johannes Mohrmann, Robert Wood, Paquita Zuidema, Christopher Bretherton, Christian Schwartz, Edwin Eloranta, Susanne Glienke, Shaunna Donaher, Mampi Sarkar, Jeremy McGibbon, Alison D. Nugent, Raymond A. Shaw, Jacob Fugal, Patrick Minnis, Robindra Paliknoda, Louis Lussier, Jorgen Jensen, J. Vivekanandan, Scott Ellis, Peisang Tsai, Robert Rilling, Julie Haggerty, Teresa Campos, Meghan Stell, Michael Reeves, Stuart Beaton, John Allison, Gregory Stossmeister, Samuel Hall, and Sebastian Schmidt

stabilized platform, the aircraft motion can be accounted for under most conditions. The above-cloud downward-looking measurements at visible and near-infrared wavelengths can be combined to produce estimates of the cloud optical depth and cloud-top effective radius following the approach of Nakajima and King (1990) . This provides additional insights into the evolving cloud properties, for example, the relationship of the cloud-top effective radius to precipitation. The upwelling broadband irradiance

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M. Christian Schwartz, Virendra P. Ghate, Bruce. A. Albrecht, Paquita Zuidema, Maria P. Cadeddu, Jothiram Vivekanandan, Scott M. Ellis, Pei Tsai, Edwin W. Eloranta, Johannes Mohrmann, Robert Wood, and Christopher S. Bretherton

(GV) aircraft, owned and operated by the National Science Foundation (NSF) and the National Center for Atmospheric Research (NCAR; Laursen et al. 2006 ), was used to make detailed measurements of aerosol, cloud, precipitation, and thermodynamic properties. The HIAPER made a total of 16 research flights (RFs) during CSET, 14 of which were transects between Sacramento, California, and Kona, Hawaii. On the outbound flight from Sacramento to Kona, detailed low-level sampling was made in 3–4 locations

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Robert Wood, Kuan-Ting O, Christopher S. Bretherton, Johannes Mohrmann, Bruce. A. Albrecht, Paquita Zuidema, Virendra Ghate, Chris Schwartz, Ed Eloranta, Susanne Glienke, Raymond A. Shaw, Jacob Fugal, and Patrick Minnis

, albeit one with 40% coverage by optically thin upper-PBL stratiform clouds. The remainder of this paper is as follows: Section 2 describes the observational datasets used and the methodological approach. Section 3 examines the statistical occurrence of both clear and cloudy UCLs including their frequency, altitude, and geographical distribution. Section 4 documents properties of both cloudy and clear UCLs using in situ G-V data. Section 5 explores several case studies from CSET, combining in

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Jothiram Vivekanandan, Virendra P. Ghate, Jorgen B. Jensen, Scott M. Ellis, and M. Christian Schwartz

drizzle or larger cloud droplets is ubiquitous in stratocumulus clouds ( Fox and Illingworth 1997 ). In the present study, radar and lidar measurements are used for detecting bulk properties of cloud and drizzle droplets remotely. In addition, airborne in situ probes provide a direct estimate of droplet diameter and LWC, but their sampling volumes are extremely limited compared to radar and lidar sample volumes. Radar reflectivity Z and lidar backscatter β of cloud and drizzle are generally

Open access
Kuan-Ting O, Robert Wood, and Christopher S. Bretherton

were commonly the veil clouds associated with aggregated Cu clusters. Visible satellite images indicate that a large fraction of clouds observed in the UCLs were optically thin ( τ < 3). In part, this is caused by the extremely low in the UCL clouds (see discussion in Part I ). Aircraft in situ measurements showed that (i) UCL coverage in CSET was as high as 40%–60% between 135° and 155°W [i.e., stratocumulus-to-cumulus transition (SCT) region with deep PBL height] but that UCLs occurred very

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Johannes Mohrmann, Christopher S. Bretherton, Isabel L. McCoy, Jeremy McGibbon, Robert Wood, Virendra Ghate, Bruce Albrecht, Mampi Sarkar, Paquita Zuidema, and Rabindra Palikonda

-scale variability is removed, possibly due to other drivers such as FT RH. That work and others have also highlighted the utility of a Lagrangian perspective for studying drivers of MBL evolution, as there is a lag in the MBL response to changing stability ( Klein et al. 1995 ) and upwind factors must be controlled for ( Mauger and Norris 2010 ). However, Eastman et al. (2016) showed that many MBL cloud properties decorrelate faster (in a day or less) following advecting boundary layer air columns (Lagrangian

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Christopher S. Bretherton, Isabel L. McCoy, Johannes Mohrmann, Robert Wood, Virendra Ghate, Andrew Gettelman, Charles G. Bardeen, Bruce A. Albrecht, and Paquita Zuidema

during each flight, with three main goals. Our first goal is to develop a composite description of the transition suitable for comparison with regional summertime climatology simulated by climate models, with an emphasis on those measurements unique to CSET. Our second goal is to briefly characterize day-to-day variability of the Sc–Cu transition and compare the space–time variation of cloud properties with our current understanding, including the correlation with “cloud-controlling factors” such as

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Mampi Sarkar, Paquita Zuidema, Bruce Albrecht, Virendra Ghate, Jorgen Jensen, Johannes Mohrmann, and Robert Wood

). For a 94-GHz radar, the Mie effect becomes apparent when drop diameters exceed 200 μ m (e.g., O’Connor et al. 2005 ), CSET radar-based precipitation estimates might be largely affected by Mie scattering. An assessment of the radar-lidar rain-rate retrieval for RF06a and RF07c is also included in section 6 . In situ precipitation is calculated from Two-Dimensional Cloud (2DC) optical array probe measurements. The probe samples drops every second across the 75–3200- μ m diameter range at 25- μ m

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