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

1. Introduction The oceans provide a vast repository of both heat and water that are of critical importance to the earth’s hydrologic and energy cycles. Because of their inherent high heat capacity relative to the atmosphere, the global oceans integrate energy exchanges across the atmospheric interface, providing both “memory” of past fluxes and a potential source of predictability for the atmosphere. These exchanges of moisture and heat with the atmosphere vary richly on a wide range of space

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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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Franklin R. Robertson, Michael G. Bosilovich, Junye Chen, and Timothy L. Miller

1. Introduction Steady progress in data assimilation efforts has produced a legacy of important contributions regarding atmospheric dynamics ( Dole 1989 ; Simmonds and Keay 2000 ; Thompson and Wallace 1998 , 2000 ; Thompson et al. 2000 ; Hoskins and Hodges 2005 ), tropical water and energy fluxes, and climate variability on interannual time scales ( Trenberth et al. 2000 , 2001 , 2008 ; Bove et al. 1998 ; Wang 2002 ). Yet, as a tool for capturing decadal-scale variability and detection

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

must first be addressed. Several studies have investigated the performance of reanalyses over the Arctic for a variety of fields including atmospheric moisture budgets ( Bromwich et al. 2000 , 2002 ), upper-level winds ( Francis 2002 ), precipitation ( Serreze and Hurst 2000 ), cloud fraction (CF) and radiative fluxes ( Walsh et al. 2009 ), and general tropospheric assessments ( Bromwich and Wang 2005 ; Bromwich et al. 2007 ). These studies, however, were based on the earlier generations of

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Kyle F. Itterly and Patrick C. Taylor

timing and intensity unrealistically force the surface water and energy budget, leading to errors in surface runoff and evaporation ( Del Genio and Wu 2010 ). Decker et al. (2012) found significant errors in the diurnal cycle of surface turbulent fluxes in reanalysis models as well. Slingo et al. (2003) evaluated the diurnal cycle of the Hadley Centre Coupled Model, version 3 (HadCM3) GCM over the tropics and found the largest differences between the GCM and observations occur over the Maritime

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

, including ground-based observed cloud, precipitation, and radiative fluxes, provide a unique dataset to evaluate these parameters from the reanalyses. The ARM SGP site is representative of a continental climate in the midlatitudes, and it has been used successfully in the past to evaluate a variety of model simulations, including the NCEP Eta Model ( Hinkelman et al. 1999 ), ECMWF ( Xie et al. 2004 ), and the NCEP Global Forecast System (GFS) ( Yang et al. 2006 ). This 3-yr comparison will assist in

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Franklin R. Robertson and Jason B. Roberts

on the Modern-Era Retrospective analysis for Research and Applications (MERRA; Rienecker et al. 2011) . More specifically, we ask what insights can MERRA, along with other observations, provide regarding the role of ISV in near-global radiative–convective adjustment and energy balance? Our focus therefore is not just on the state variables, but also on the energy fluxes. As noted by Kalnay et al. (1996) precipitation, turbulent fluxes, and cloud radiative effects derived from reanalyses

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Mark Decker, Michael A. Brunke, Zhuo Wang, Koichi Sakaguchi, Xubin Zeng, and Michael G. Bosilovich

cycle that is much too large over land during the warm seasons ( Janowiak et al. 1998 ). Similarly, Berg et al. (2003) found that the NCEP–NCAR reanalysis and ERA-40 have substantial biases in 2-m air and dewpoint temperatures, surface radiative fluxes, and precipitation over land in North America as compared with various gridded datasets. Aside from the atmospheric fields used to force land surface models, evapotranspiration during the warm season over the U.S. Great Plains region has also been

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

study focuses on global land areas with additional emphasis on northern high-latitude regions (>45°N), where terrestrial carbon, water, and energy fluxes provide potentially important climate feedbacks and modeling efforts rely heavily on global reanalysis data. 2. Data The datasets and in situ observations used for evaluation and validation of the MERRA land parameters in this study are summarized in Table 1 . We evaluated GEOS-4 and MERRA surface meteorological data against AMSR-E [University of

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

1. Introduction In recent decades, reanalysis has emerged as an effective way to combine numerical model output with information from a diverse suite of atmospheric state measurements such that the proper relationships between dynamics, thermodynamics, radiation, and surface fluxes are preserved ( Kalnay et al. 1996 ; Uppala et al. 2005 ; Onogi et al. 2005 ; Rienecker et al. 2011 ). In large part because these datasets provide a long-term dynamically consistent and multivariate

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