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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

The evolution of the boundary layer aerosol, cloud, precipitation, and thermodynamic structures along trajectories within the North Pacific trade winds was investigated using the NSF–NCAR Gulfstream V. Boundary layer clouds in the form of stratocumulus and small marine cumulus are the most frequently observed cloud types over the Earth’s oceans, are the most abundant types globally ( Norris 1998 ), and have an important impact on the Earth’s radiation budget ( Hartmann and Short 1980 ). The

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

1. Introduction The transition from overcast stratocumulus to more broken shallow cumulus clouds is a conspicuous feature of all of Earth’s subtropical oceanic basins. The accompanying change in the top-of-the-atmosphere albedo, and the contribution to global hydrologic cycle through evaporation off the ocean’s surface as the boundary layers deepen, has inspired research into the processes underlying the stratocumulus-to-cumulus transition (SCT). The original studies established that the

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Johna E. Rudzin, Lynn K. Shay, and Benjamin Jaimes de la Cruz

1. Introduction The Caribbean Sea is a frequent pathway for tropical cyclones (TCs); these storms encounter several different ocean regimes such as the Amazon–Orinoco River plume, the Caribbean Current, the Yucatan Current, and large warm-core eddies (WCEs) that reside in the basin. During the late summer months of the Atlantic hurricane season, sea surface temperature (SST) remains fairly homogeneous throughout the basin ( Fig. 1 ). Yet, ocean heat content relative to the 26°C isotherm [OHC

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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

1. Introduction The climatological stratocumulus to cumulus (Sc–Cu) transition over the eastern subtropical oceans has been a long-standing test of our physical understanding and modeling skill. Through a combination of field and satellite observations and detailed process modeling such as large-eddy simulation (LES), the Sc–Cu transition has been explained as due to the deepening and warming of a cloud-topped marine boundary layer under a strong inversion as it advects toward warmer sea

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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

1. Introduction A physically reasonable treatment of low clouds within climate models is required for the realistic modeling of the climate’s sensitivity to greenhouse gas forcing (e.g., Wetherald and Manabe 1988 ; Tiedtke 1993 ; Stephens 2005 ). Furthermore, low clouds account for a great deal of intermodel variability in cloud feedback factors ( Bony and Dufresne 2005 ; Zhang et al. 2013 ). One persistent difficulty with modeling marine boundary layer (MBL) clouds is accurately capturing

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Bradley W. Klotz and David S. Nolan

comparisons of observational or model data to it. The uncertainty of this intensity measure is 5 m s −1 ( Landsea and Franklin 2013 ), which is slightly lower for weak tropical storms and higher for strong hurricanes. Despite these caveats, the best track intensity is a reasonable baseline value to assess the current strength of a TC. In the absence of aircraft data, TC intensity is estimated from the satellite technique developed by Dvorak (1975 , 1984 ). While the Dvorak method is extremely useful

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Patrik Benáček and Máté Mile

inaccuracies of the NWP model like parameterization, spatial and temporal discretization, the imperfect use of boundary conditions, and unrepresented physical and dynamical processes ( Lahoz et al. 2010 ; Torn and Davis 2012 ; Romine et al. 2013 ). The observation biases involve instrument error (e.g., poor calibration), approximations in forward operator and data processing such as the radiative transfer model or cloud detection ( Auligné et al. 2007 ). This creates a complex bias depending on, for

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Vasubandhu Misra and Amit Bhardwaj

), positive (negative) values on the y axis refer to the meridional MSLP gradient lagging (leading) the onset date of the NEM. Similarly, in (b), positive (negative) values on the y axis refer to the meridional MSLP gradient leading (lagging) the demise date of the NEM. b. Seasonal variations of upper-ocean variables The tropical northern Indian Ocean is unique in that its western boundary current evolves with seasonal reversal of directions from southwest to northeast during the SISM and NEM seasons

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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

1. Introduction Assessment of the physical factors controlling the coverage and albedo of marine boundary layer (MBL) clouds remains a pressing challenge. The speed at which the stratocumulus (Sc)-to-cumulus (Cu) transition (SCT) occurs in air masses downstream of the eastern subtropical ocean basins determines the albedo of the tropics, and similar cloud transitions in postfrontal air masses are important for determining midlatitude storm-track albedo. These transitions in cloudiness are

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

of warm subsurface water, triggered the mass loss and instability of 79N and nearby glaciers. It has also been shown that the northeast ice stream was sensitive to subtle changes in climate, and regularly underwent ice extent fluctuations and changes in margin (ice edge) location, in the last 45 000 years ( Larsen et al. 2018 ). Zachariae Isstrøm is a glacier immediately to the south of 79N (78.0°N), which currently loses 5 Gt yr −1 of ice ( Mayer et al. 2018 ). It is likely that the higher

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