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Edward Armstrong, Paul Valdes, Jo House, and Joy Singarayer

surface albedo and reduced SW energy at the surface. Replacement of natural vegetation with C3 and C4 gases increases the maximum canopy/snow albedo parameters in the model ( Cox 2001 ) and reduces LAI. The net surface shortwave energy anomaly peaks in the summer months during periods of highest insolation, whereas the surface albedo anomaly peaks in the winter months due to a significant increase in snow cover. The way in which CO 2 alters the surface energy balance is discussed in section 4 . It

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G. Strandberg and E. Kjellström

.6 and 0.85; the albedo decreases as snow ages. For snow-covered land areas in forest regions, the albedo is set constant to 0.2. The snow-free albedo is set to 0.15 and 0.28 for forest and forest-free areas, respectively ( Samuelsson et al. 2011 ). The root depth varies from around 1.5 m for open land to 2 m for forest ( Champeaux et al. 2005 ). Surface resistance depends on a vegetation-dependent minimum surface resistance, LAI, photosynthetically active radiation, water stress, vapor pressure

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Jean-Sébastien Landry, Navin Ramankutty, and Lael Parrott

, we also validated that the robustness (and not only the magnitude) of the improvement increased with . 3.2. Limitations of the HLM Our computation of through Equation (1) implicitly assumed that and did not vary with the age of each patch. This assumption was a reasonable first-order approximation for treeless areas, especially for the snow-cover period, but not for tree-covered areas ( Amiro et al. 2006 ). Accounting for the age dependence of albedo in tree-covered areas should increase

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W. L. Ellenburg, R. T. McNider, J. F. Cruise, and John R. Christy

United States during 1950–2000 . J. Climate , 22 , 2571 – 2590 , doi: 10.1175/2008JCLI2359.1 . Wang , Z. , and Coauthors , 2014 : Evaluation of MODIS albedo product (MCD43A) over grassland, agriculture and forest surface types during dormant and snow-covered periods . Remote Sens. Environ. , 140 , 60 – 77 , doi: 10.1016/j.rse.2013.08.025 . Wetzel , P. J. , and J.-T. Chang , 1987 : Concerning the relationship between evapotranspiration and soil moisture . J. Climate Appl. Meteor

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A L. Hirsch, A. J. Pitman, J. Kala, R. Lorenz, and M. G. Donat

provide consistent estimates of the impact of LUC on temperature extremes or whether differences in land–atmosphere coupling directly influence how LUC affects the model simulations. We note here that we are not attempting to predict the real impact of LUC. Instead, we are examining the sensitivity of the simulated impact as a function of model structure, land cover, and physics (PBL and cumulus convection) to determine whether single-model estimates of the impact of LUC can be reliable. We focus on

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Weiyue Zhang, Zhongfeng Xu, and Weidong Guo

1. Introduction Human activities have altered 42%–68% of the global land surface by transforming natural vegetation into crops, pastures, and woods for harvesting from the years 1700 to 2000 ( Hurtt et al. 2006 ). The biogeophysical climate impacts of human-induced land-cover change have been investigated using various general circulation models (GCM), regional climate models, and observations (e.g., Pielke et al. 2002 ; Fu 2003 ; Feddema et al. 2005 ; Bonan 2008 ). The Fifth Assessment

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Pedro Sequera, Jorge E. González, Kyle McDonald, Steve LaDochy, and Daniel Comarazamy

surroundings as a consequence of urban/rural thermal energy budget differences ( Oke 1982 ). The magnitude and characteristics of the UHI are controlled by several factors. In general, UHI decreases with increasing wind speed and cloud cover, while it increases with city size and population density; it is also stronger during summer and, typically, the nighttime, depending on location ( Arnfield 2003 ). Even though the general UHI pattern is similar in all urban environments, each city is exposed to

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Dev Niyogi, Ming Lei, Chandra Kishtawal, Paul Schmid, and Marshall Shepherd

, 2007 : An overview of regional land-use and land-cover impacts on rainfall . Tellus , 59B , 587 – 601 , doi: 10.1111/j.1600-0889.2007.00251.x . 10.1111/j.1600-0889.2007.00251.x Pielke , R. A. , Sr. , and Coauthors , 2011 : Land use/land cover changes and climate: Modeling analysis and observational evidence . Wiley Interdiscip. Rev.: Climate Change , 2 , 828 – 850 , doi: 10.1002/wcc.144 . Rosenfeld , D. , 2000 : Suppression of rain and snow by urban and industrial air pollution

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Soumaya Belmecheri, Flurin Babst, Amy R. Hudson, Julio Betancourt, and Valerie Trouet

NHJ, we used the Twentieth Century Reanalysis, version 2, dataset (20CR; Compo et al. 2011 ), which covers the period 1871–2012 with a 2° spatial resolution and a 1-month temporal resolution. Early meteorological observations are strongly affected by inhomogeneity due to changing station density ( Donat et al. 2011 ). We therefore limited our analysis to the period 1930–2012, which composes a suitable time frame to investigate NHJ variability at interannual to decadal time scales, but we

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