Search Results

You are looking at 1 - 9 of 9 items for :

  • Infrared radiation x
  • CCSM4/CESM1 x
  • All content x
Clear All
S. J. Ghan, X. Liu, R. C. Easter, R. Zaveri, P. J. Rasch, J.-H. Yoon, and B. Eaton

Boucher 2000 ; Myhre 2009 ), indirect effects ( Lohmann and Feichter 2005 ), and semidirect effects ( Hansen et al. 1997 ; Koch and Del Genio 2010 ). The term aerosol direct effects refers to the direct impact of anthropogenic aerosol particles on the planetary energy balance through scattering, absorption, and emission of radiation in the atmosphere, without consideration of the aerosol effects of the radiative heating on clouds. Aerosol indirect effects refer to the impact through the

Full access
Marika M. Holland, David A. Bailey, Bruce P. Briegleb, Bonnie Light, and Elizabeth Hunke

temperature, etc.). The CCSM4 atmosphere provides shortwave fluxes for direct–diffuse radiation in two spectral bands: 0.2–0.7 μ m and 0.7–5.0 μ m. The CCSM4 sea ice radiation scheme subdivides the near-infrared band into two subbands, 0.7–1.19 μ m and 1.19–5.00 μ m, to better represent radiation penetration through thin snow and sea ice. It also distinguishes direct from diffusely scattered radiation. The native vertical structure of the CCSM4 sea ice component is one snow layer (if present

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

and February. Additionally, while they considered ERA-40 to provide a valuable description of the atmospheric energy budget, they noted significant issues with top of the atmosphere (TOA) radiation, net surface flux (both due in part to snow and ice albedo parameterization) and the resulting residual transport terms, and that these terms were different from the NRA. Porter et al. (2010) expanded on this analysis, comparing energy budgets from the NRA and the Japan Meteorological Society (JRA

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

between absorbed solar radiation and net infrared radiation at the surface. The seasonal variability of albedo and certain moisture fluxes also increases with interactive nitrogen. In CDV, the expansive tree cover again suppresses seasonal fluctuations in albedo, particularly during the winter months when the trees partially mask the snow-covered ground. The difference between the maximum and minimum albedo in the seasonal cycle is 0.1362 in CDV compared to 0.1439 and 0.1430 in CNDV and CN

Full access
Richard B. Neale, Jadwiga Richter, Sungsu Park, Peter H. Lauritzen, Stephen J. Vavrus, Philip J. Rasch, and Minghua Zhang

( Vavrus and Waliser 2008 ). 2) Consistent cloud fraction calculation To prevent inconsistent values of total cloud fraction and condensate being passed to the radiation parameterization in CAM4, a second updated cloud fraction calculation is performed. Cloud fraction, and therefore relative humidity, is now thermodynamically consistent with condensate values on entry to the radiation parameterization. This vastly reduces the frequency of empty clouds seen in the CAM3, where cloud condensate was zero

Full access
J. E. Kay, B. R. Hillman, S. A. Klein, Y. Zhang, B. Medeiros, R. Pincus, A. Gettelman, B. Eaton, J. Boyle, R. Marchand, and T. P. Ackerman

lidar on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and 6) Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a lidar (PARASOL). Although ISCCP observations are available over the longest period (1983–present) of any of the satellite datasets, MODIS (2002–present), and MISR (2000–present) observations are derived from more sophisticated passive retrievals based on more angles (MISR) and more spectral bands (MODIS

Full access
David M. Lawrence, Keith W. Oleson, Mark G. Flanner, Christopher G. Fletcher, Peter J. Lawrence, Samuel Levis, Sean C. Swenson, and Gordon B. Bonan

is reduced from +0.5% in CCSM3 to 0.0% in CCSM4 and the centered RMSE is reduced from 5.8% in CCSM3 to 2.1% in CCSM4. The MODIS all-sky albedo is derived from the black-sky (direct) and white-sky (diffuse) near-infrared and visible wave band albedos by weighting them according to the CCSM partitioning of solar radiation into these components. MODIS data are from collection 4 and are the climatological average of years 2001–2003. Snow cover area and snow cover fraction, which together exert strong

Full access
William H. Lipscomb, Jeremy G. Fyke, Miren Vizcaíno, William J. Sacks, Jon Wolfe, Mariana Vertenstein, Anthony Craig, Erik Kluzek, and David M. Lawrence

a prescribed value in the visible and near-infrared bands. In the simulations described below, the visible and near-IR ice albedos are 0.60 and 0.40, respectively, in approximate agreement with observed values for melting glacier ice (e.g., Bøggild et al. 2010 ). In the standard version of CLM, the snow depth is limited to H max = 1 m liquid water equivalent (LWE), and any additional snow runs off to the ocean. When glacier ice melts, the meltwater remains in place until it refreezes. (In

Full access
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

understanding of CO 2 , including the magnitude of sources and sinks ( Gurney et al. 2002 ; Stephens et al. 2007 ; Yang et al. 2007 ). In this study, we analyzed the three-dimensional structure of atmospheric CO 2 in one example of such coupled models, the Community Earth System Model (CESM). In the version of CESM used here (CESM1-BGC), atmospheric CO 2 is represented as a three-dimensional atmospheric tracer, which, in the simulations described here, influenced the atmospheric radiation budget and

Full access