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Jenny Lindvall, Gunilla Svensson, and Cecile Hannay

turbulent parameters: for example, the surface heat fluxes. A more comprehensive study from the PBL point of view is reported in Garratt et al. (2002) , where they compared 5 yr of GCM results with detailed boundary layer observations at six locations, two over the ocean and four over land. The observational data was limited to hourly data for a month or two at each site. They found overall good agreement between the observations and the model except for some unrealistic model mixed-layer temperature

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Susan C. Bates, Baylor Fox-Kemper, Steven R. Jayne, William G. Large, Samantha Stevenson, and Stephen G. Yeager

1. Introduction The coupling between the atmosphere and ocean is a major player in the earth’s climate system and governor of climate change. The former has a limited capacity to store water and heat but is connected to the ocean, which is effectively an infinite reservoir of water and has more heat capacity in only its upper few meters than exists in the entire atmosphere. The direct coupling of the planetary boundary layers (PBLs) is accomplished through the air–sea fluxes. In nature, the

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Stephen Yeager, Alicia Karspeck, Gokhan Danabasoglu, Joe Tribbia, and Haiyan Teng

region. Imbalances between the net surface heat flux (SFLX), which cools the SPG box, and the net advective and diffusive fluxes (ADV and DIFF), which both warm the SPG box, generate nonzero heat content tendency (TEND = SFLX + ADV + DIFF). The 1961–2007 averages are 1, −60, 47, and 14 W m −2 for TEND, SFLX, ADV, and DIFF, respectively, so there is a slight upward trend in SPG temperature during the 47-yr period being analyzed. The heat budget components in Fig. 3 are plotted as anomalies from

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Samuel Levis, Gordon B. Bonan, Erik Kluzek, Peter E. Thornton, Andrew Jones, William J. Sacks, and Christopher J. Kucharik

Plains of North America. Tsvetsinskaya et al. found that replacing the regional climate model’s generic crop formulation with the more realistic representation of corn from a crop model led to improvements in the simulated leaf area index (LAI). These improvements generated differences in the simulated turbulent heat fluxes, which led to changes in temperature, humidity, winds, and precipitation. At interannual time scales the largest changes were found during drought years and at diurnal time scales

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C. Kendra Gotangco Castillo, Samuel Levis, and Peter Thornton

to assess the relative importance of interactive nitrogen versus interactive biogeography in present-day equilibrium simulations. This is part of the broader CESM1 model documentation for inclusion in the special collection of CESM1 articles. 2. Methods A complete spin-up of the dynamic vegetation in this model requires first establishing the carbon and nitrogen pools and fluxes. The process for spinning up CN is documented elsewhere ( Kluzek 2011 ; Thornton et al. 2007 ; Thornton and

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Matthew C. Long, Keith Lindsay, Synte Peacock, J. Keith Moore, and Scott C. Doney

.e., atmosphere, land, ocean, and sea ice). In the ocean-ice integrations, the ocean and ice component models are forced by atmospheric observations and reanalyses, following the Coordinated Ocean–Ice Reference Experiments (CORE; Griffies et al. 2009 ) protocol. In these, the ocean-ice model is forced with sea–air fluxes of heat, freshwater, and momentum derived using a methodology ( Large and Yeager 2009 ) combining 6-h surface wind, temperature, specific humidity, and density from the National Centers for

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Jennifer E. Kay, Marika M. Holland, Cecilia M. Bitz, Edward Blanchard-Wrigglesworth, Andrew Gettelman, Andrew Conley, and David Bailey

. Because the definition of Arctic amplification affects the identification of processes explaining Arctic amplification, we begin by defining Arctic amplification for the purposes of this study as the greater-than-global Arctic air or surface temperature warming in response to increased greenhouse gases. Both local feedbacks, such as the canonical positive surface albedo feedback (SAF), and heat flux convergence have been shown to affect Arctic warming and amplification in response to increased

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Gretchen Keppel-Aleks, James T. Randerson, Keith Lindsay, Britton B. Stephens, J. Keith Moore, Scott C. Doney, Peter E. Thornton, Natalie M. Mahowald, Forrest M. Hoffman, Colm Sweeney, Pieter P. Tans, Paul O. Wennberg, and Steven C. Wofsy

only on human-mediated fluxes, such as those from fossil fuel combustion or land use change, but also on the response of the natural carbon cycle to changing atmospheric composition and climate ( Fung et al. 2005 ). Currently, 55% of CO 2 emitted by human activities is taken up by the ocean or terrestrial ecosystems, with 45% remaining airborne ( Le Quéré et al. 2009 ). The degree to which the efficiency of these sinks will change with climate is an open question, with implications for the rate of

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Peter J. Lawrence, Johannes J. Feddema, Gordon B. Bonan, Gerald A. Meehl, Brian C. O’Neill, Keith W. Oleson, Samuel Levis, David M. Lawrence, Erik Kluzek, Keith Lindsay, and Peter E. Thornton

1. Introduction Recent studies have shown that historical human land use and land cover change have significantly impacted the earth’s climate through changes in the carbon cycle, through altered biogeochemical processes ( Houghton 2003 ; Canadell et al. 2007 ; Bonan 2008 ; Shevliakova et al. 2009 ) and through changes in energy and moisture fluxes to the atmosphere, by altering biogeophysical processes ( Betts et al. 2001 ; Feddema et al. 2005 ; Findell et al. 2007 ; Bala et al. 2007

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Gijs de Boer, William Chapman, Jennifer E. Kay, Brian Medeiros, Matthew D. Shupe, Steve Vavrus, and John Walsh

surface wind speed and direction, temperature, and precipitation. Wind speed and direction are particularly important in the Arctic for advection of simulated sea ice ( DeWeaver and Bitz 2006 ) and governance of heat fluxes between the ocean–land surface and atmosphere. Chapman and Walsh (2007) also evaluated simulated Arctic SLP. In general, ESM-simulated storm tracks were demonstrated to be shorter than those observed, with observed storms often reaching the Kara Sea and simulated storm tracks

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