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J. Brent Roberts, Franklin R. Robertson, Carol A. Clayson, and Michael G. Bosilovich

fluxes. These lowest model level variables are affected in part by the planetary boundary layer (PBL) scheme. The PBL parameterization relies on the Lock et al. (2000) scheme during unstable conditions but uses components of the Louis et al. (1982) scheme under stable regimes. Neutral transfer coefficients are computed based on standard similarity relationships using a momentum roughness length based on Charnock (1955) , a roughness length for heat based on Beljaars (1995) , and a roughness

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Aaron D. Kennedy, Xiquan Dong, Baike Xi, Shaocheng Xie, Yunyan Zhang, and Junye Chen

assimilation technology. Because the errors of reanalyses and their underlying models are relatively unknown, their benefit for answering more complex questions involving the climate is questionable. For this reason, reanalyses have been used sparingly to generate forcing that provides initial and boundary conditions for single-column model (SCM) and cloud-resolving model (CRM) studies that can help develop improvements for general circulation models (GCMs). To circumnavigate these issues, extensive work

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Michael A. Brunke, Zhuo Wang, Xubin Zeng, Michael Bosilovich, and Chung-Lin Shie

1. Introduction The atmosphere and ocean interact at their interface through surface turbulent fluxes of temperature [sensible heat (SH)], moisture [latent heat (LH)], and momentum (wind stress τ ). Knowledge of these fluxes is important to understand the ocean heat and freshwater budget and the partitioning of the global pole-to-equator heat transport between the atmosphere and the ocean. The fluxes are also needed to provide a boundary condition for both atmospheric and ocean models and are

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Yonghong Yi, John S. Kimball, Lucas A. Jones, Rolf H. Reichle, and Kyle C. McDonald

land surface hydrological processes through explicit modeling of subgrid-scale soil moisture variability and its effect on runoff and evaporation ( Koster et al. 2000 ). The basic computational unit of the model is the hydrological catchment (or watershed), with boundaries defined by topography. Within each element, the vertical profile of soil moisture is given by the equilibrium soil moisture profile and deviations from the equilibrium profile in a 0–2-cm surface layer and 0–100-cm “root zone

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Michele M. Rienecker, Max J. Suarez, Ronald Gelaro, Ricardo Todling, Julio Bacmeister, Emily Liu, Michael G. Bosilovich, Siegfried D. Schubert, Lawrence Takacs, Gi-Kong Kim, Stephen Bloom, Junye Chen, Douglas Collins, Austin Conaty, Arlindo da Silva, Wei Gu, Joanna Joiner, Randal D. Koster, Robert Lucchesi, Andrea Molod, Tommy Owens, Steven Pawson, Philip Pegion, Christopher R. Redder, Rolf Reichle, Franklin R. Robertson, Albert G. Ruddick, Meta Sienkiewicz, and Jack Woollen

surface meteorological conditions (precipitation, radiation, wind speed, etc.) generated by the AGCM during the corrector segment. b. Boundary and ancillary data Unlike more recent versions of the GEOS-5 system, the MERRA AGCM uses a climatological aerosol distribution generated using the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) model with transport based on a previous (GEOS-4) version of the AGCM ( Colarco et al. 2010 ). The MERRA AGCM does, however, use the analyzed ozone

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Rolf H. Reichle, Randal D. Koster, Gabriëlle J. M. De Lannoy, Barton A. Forman, Qing Liu, Sarith P. P. Mahanama, and Ally Touré

computational unit of the model is the hydrological catchment (or watershed), with boundaries defined by topography (see below). Within each element, the vertical profile of soil moisture is given by the equilibrium soil moisture profile and the deviations from the equilibrium profile (described by variables in a 0–2-cm surface layer and in a “root zone” layer that extends from the surface to a depth z R , with 75 cm ≤ z R ≤ 100 cm depending on local soil conditions). The spatial variability of soil

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Derek J. Posselt, Andrew R. Jongeward, Chuan-Yuan Hsu, and Gerald L. Potter

instrument energy point spread function ( Minnis et al. 1997 ). CERES on TRMM was only operational during January–August 1998 and March 2000; however, these periods correspond to the rapid 1998 El Niño–La Niña transition during January–August 1998 and to La Niña conditions during March 2000. A detailed description of the TRMM instrument packages can be found in Kummerow et al. (1998) and the CERES SSF data are documented online (at http://ceres.larc.nasa.gov/products.php?product=SSF-Level2 ). Cloud

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Behnjamin J. Zib, Xiquan Dong, Baike Xi, and Aaron Kennedy

sea ice concentration fields ( Rayner et al. 2003 ) for prescribed boundary conditions ( Compo et al. 2011 ). As a result, a global analysis of the atmospheric state along with an uncertainty estimate is produced, which covers the entire twentieth century (1871–present). Such a long-term dataset can be advantageous in understanding the full range of variability in climate processes and extreme events while also providing significant information on long-term climate trends. The coupled atmosphere

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Brian E. Mapes and Julio T. Bacmeister

the highest echo-top altitude of the whole display. It is isolated and narrow, however, quite distinct from the wide, overlapping mesoscale echo objects in the main active phases (3–6 in this random sample from MJO events in 2006–09). Also consistently, lightning peaks in off-peak phases of the MJO ( Morita et al. 2006 ), indicating intense but sparse convection in conditions like phase 2. Based on all of these indications, it appears that the lifted-parcel instability driving isolated

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Michael G. Bosilovich, Franklin R. Robertson, and Junye Chen

, and a residual that results from maintaining energy balance in the presence of numerical dissipation, each of which are also included in the output diagnostics ( Suarez et al. 2011 ). The vertically integrated radiation term can be expanded to its top of the atmosphere and surface boundary conditions: The radiation term includes solar [net shortwave (SW), at the top of the atmosphere T and at the surface S ] radiation, the net surface longwave radiation (LW S ), and the outgoing longwave

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