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Richard H. Johnson and Paul E. Ciesielski

soundings. The smaller dimension of Malé compared with Gan argues for a smaller heat-island effect there; nevertheless, land effects cannot be ignored in the interpretation of the lowest 50 m of the Malé soundings. The soundings from Revelle are the most representative of open-ocean conditions, but the ship superstructure no doubt impacted the lowest 50 m or so for some of the soundings. 3. Results a. Mean properties of the mixed layer The focus of the study is on well-mixed boundary layers, which can

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Simon P. de Szoeke

1. Introduction Processes that control the moist static energy (MSE) of the boundary layer (BL) determine updraft buoyancy, affecting deep convection that drives the atmospheric circulation ( Raymond 1995 ; Neelin and Zeng 2000 ; DeMott et al. 2015 ). Climate models with stronger mixing of water vapor between the atmospheric BL and the free troposphere have stronger positive low-cloud feedback and stronger climate sensitivity to greenhouse gases ( Sherwood et al. 2014 ), yet the mechanism for

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Eric D. Skyllingstad and Simon P. de Szoeke

systems affect the environment leading up to the active phase of the MJO. The paper begins with a description of the coupled large-eddy simulation model, its initial conditions, and its boundary conditions in section 2 . In section 3 , results from a basic case simulation are presented with an analysis of cold pool formation. Section 4 compares the heat and moisture budgets from the suite of experiments. The role of ocean surface properties is presented in section 5 . Section 6 summarizes the

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H. Bellenger, R. Wilson, J. L. Davison, J. P. Duvel, W. Xu, F. Lott, and M. Katsumata

) suggested that the usually neglected free-tropospheric clear-air turbulent mixing might also play some role in vertical moisture transport in the presence of steep vertical gradients of moisture above the boundary layer as observed during the suppressed phase of the MJO or in conjunction with dry intrusions. Fig . 1. Locations of the observation sites and research vessels stations (triangles) for the MISMO (blue), CIRENE (green), and C/D (red) experiments. Positions and tracks of vortices ( Duvel 2015

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James H. Ruppert Jr. and Richard H. Johnson

) in the Indian Ocean and ceases in the central Pacific Ocean ( Madden and Julian 1972 ; Hendon and Salby 1994 ; Wheeler and Hendon 2004 ). During the transition from suppressed to active conditions in the MJO (from an Eulerian viewpoint), the prevailing character of convective clouds evolves from shallow cumulus, to congestus, to deep cumulonimbus as the free troposphere transitions from dry, to moist up to midlevels, to fully moistened, respectively ( DeMott and Rutledge 1998 ; Johnson et al

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Simon P. de Szoeke, Eric D. Skyllingstad, Paquita Zuidema, and Arunchandra S. Chandra

active MJO conditions . J. Geophys. Res. Atmos. , 120 , 10 324 – 10 350 , doi: 10.1002/2014JD022948 . 10.1002/2014JD022948 Saxen , T. R. , and S. A. Rutledge , 1998 : Surface fluxes and boundary layer recovery in TOGA COARE: Sensitivity to convective organization . J. Atmos. Sci. , 55 , 2763 – 2781 , doi: 10.1175/1520-0469(1998)055<2763:SFABLR>2.0.CO;2 . 10.1175/1520-0469(1998)055<2763:SFABLR>2.0.CO;2 Schlemmer , L. , and C. Hohenegger , 2014 : The formation of wider and deeper

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David M. Zermeño-Díaz, Chidong Zhang, Pavlos Kollias, and Heike Kalesse

available directly from observations. Large-scale cloud distributions during the life cycle of the MJO have been studied largely using satellite observations ( Lau and Wu 2003 ; Masunaga et al. 2008 ; Riley et al. 2011 ; Del Genio et al. 2012 ; Barnes and Houze 2013 ). These observations have shown a relatively large population of shallow clouds during suppressed phases of the MJO. The detection of shallow clouds from space is challenging because of partial beam-filling conditions (cloud sizes

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Sue Chen, Maria Flatau, Tommy G. Jensen, Toshiaki Shinoda, Jerome Schmidt, Paul May, James Cummings, Ming Liu, Paul E. Ciesielski, Christopher W. Fairall, Ren-Chieh Lien, Dariusz B. Baranowski, Nan-Hsun Chi, Simon de Szoeke, and James Edson

/DYNAMO period are 1–14 October, 6–16 November, 6–12 December, and 29 December to 9 January. The focus of this study is to investigate the moisture resurgence processes during the suppressed phase prior to the November MJO that covers a 4-day period between 12–16 November (~10 days prior to the MJO2 initiation in the DYNAMO array). The coupled hindcast simulations consist of a three-component (air–ocean–wave), six-way fully coupled run using the initial and boundary conditions from the real-time COAMPS run

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Xiouhua Fu, Wanqiu Wang, June-Yi Lee, Bin Wang, Kazuyoshi Kikuchi, Jingwei Xu, Juan Li, and Scott Weaver

. Figures 2a and 2b show the phase diagrams of the observations and forecasts under different SST settings ( Table 1 ) for a period of one month with two different initial conditions. For the case initialized on 7 October ( Fig. 2a ), the observed initial MJO is in phase 7 with a convective center in western Pacific ( Figs. 3a and 4a ). Regardless of what SST boundary conditions were used, all four forecasts capture the eastward propagation and the reinitiation of the October MJO in the Indian Ocean

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Brandon W. Kerns and Shuyi S. Chen

when the data are updated with new swaths. Also, moderate changes in midlevel moisture with the boundary layer and upper levels remaining moist are not easily distinguished in terms of TPW. For these reasons, the evolution of TPW is most useful at determining strong gradients between moist (>~55 mm) and dry air (<~45 mm) masses, where there are large gradients of moisture through a deep layer of the atmosphere. Fortunately, these sharp moisture gradients are common ( Zhang et al. 2003 ). 3

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