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

). Collision–coalescence increases not only the size of water droplets but also size of the aerosol inside. The advantage of the 2D bin framework is that the resulting aerosol mass can be saved after collision–coalescence takes place, which may be important for the temporal evolution of DSDs. The hybrid bin scheme developed by Chen and Lamb (1994 ; CL scheme) is applied to treat condensation and evaporation processes. The two-dimensional flux method developed by Bott (2000 ; Bott scheme) is used to treat

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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

fluxes increase over warmer waters ( Bretherton and Wyant 1997 ; Wyant et al. 1997 ). As several studies have shown ( Martin et al. 1995 ; Zhou et al. 2015 ), stratocumulus cloud breakup is not an immediate response to MBL decoupling but can be delayed by as much as 1–3 days with cloud cover often remaining above 50% until 500–2000 km downstream of decoupling onset ( Zhou et al. 2015 ). Given the importance of the SCT, it is remarkable that few dedicated aircraft observations have sampled the MBL

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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

shallow Sc-topped MBLs over cool coastal waters advect westward and equatorward in the trade winds, the boundary layer deepens and eventually the Sc cloud breaks up, leaving behind a cumulus MBL with lesser cloud fraction. The dynamics of the marine cloud-topped boundary layer has a rich history of investigation. Early seminal work was performed by Lilly (1968) , who explored cloud-topped MBL mixing, crucially describing the role of cloud -top radiative cooling in driving MBL mixing (in contrast to

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Jenny V. Turton, Thomas Mölg, and Dirk Van As

the KPC weather stations ( van As 2011 ). During summer at KPC_U, 26% of days have a cloud-cover fraction of less than 0.1 (clear skies), while during winter, this number decreases to 6% of days. Similarly, during winter, 32% (219 days) of days observed a cloud-cover fraction of greater than 0.9 (full cloud cover), whereas in summer, only 6% of days experience overcast conditions. Over the Arctic Ocean, two well-defined wintertime cloud states have been identified from observations; radiatively

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

shallow cloud transition is primarily dependent upon the ratio of surface latent heat fluxes to cloud-top longwave radiative cooling ( Krueger et al. 1995 ; Bretherton and Wyant 1997 ). More recent research has focused on articulating the pace of the transition. One comprehensive analysis of Lagrangian trajectories based on reanalyses and satellite observations concluded that changes in the underlying sea surface temperature, more so than in the atmosphere, dominate the speed of the cloud transition

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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

energy and moisture fluxes associated with these clouds are critical in maintaining the thermodynamic structure of the lower troposphere. Thus, both the turbulent mixing and the radiative impact on the surface associated with marine boundary layer (MBL) clouds need to be adequately parameterized in large-scale models ( Bony and Dufresne 2005 ). The inadequate representation of MBL cloud processes in large-scale models continues to be a major contributor to model uncertainties in cloud feedback

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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

and deepening of the marine boundary layer, in which turbulence entrains free-tropospheric air through the MBL’s top ( Bretherton and Wyant 1997 ; Sandu and Stevens 2011 ). Other proposed mechanisms that influence the characteristics of the transition, as opposed to the occurrence of the transition itself, include the precipitation flux within the MBL, changes in the large-scale subsidence, diurnal variations in the warming of the MBL clouds, changes in the water vapor above the MBL, and changes

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