To evaluate and improve the treatment of clouds and radiation by the climate models of the National Center for Atmospheric Research (NCAR), simulations by the NCAR Community Climate Model version 3 (CCM3), as well as the recently released Community Atmosphere Model version 2 (CAM2), are examined. The Rasch and Kristjánsson prognostic cloud condensate scheme, which is now the standard scheme for...

A 300-yr simulation with the NCAR Climate System Model (CSM), version 1, captured only ;60% of the observed ENSO signal and exaggerated the interannual variability of SST in the western tropical Pacific. Here, a simulation with a new version of the CSM, which significantly improves the spatial and temporal patterns of tropical Pacific variability, is described. Maximum SST variability is shifte...

The boreal winter Madden–Julian oscillation (MJO) remains very weak and irregular in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 2 (CAM2) as in its direct predecessor, the Community Climate Model version 3 (CCM3). The standard version of CAM2 uses the deep convective scheme of Zhang and McFarlane, as in CCM3, with the closure dependent on convective av...

Deep ocean circulation may be a significant factor in determining climate. Here, we describe two long, fully coupled atmosphere-ocean simulations with the NCAR Climate System Model (CSM) for the late Cretaceous (80 Ma). Our results suggest that higher levels of atmospheric CO2 and the altered paleogeography of the late Cretaceous resulted in a surface ocean state temperature, salinity, and circ...

Impact of mixing and chemical change on ozone-tracer relations in the polar vortex R. Müller, S. Tilmes, P. Konopka, J.-U. Grooß, and H.-J. Jost ICG I, Forschungszentrum Jülich, 52425 Jülich, Germany Bay Area Envrionmental Research Institute, Sonoma, CA, USA now at: ACD, NCAR, Boulder, CO, USA Received: 8 June 2005 – Accepted: 6 July 2005 – Published: 10 August 2005 Correspondence to: R. Müller...

Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR...

Characterizing mega-city pollution with TES O3 and CO measurements C. Shim, Q. Li, M. Luo, S. Kulawik, H. Worden, J. Worden, A. Eldering, G. Diskin, G. Sachse, A. Weinheimer, D. Knapp, D. Montzca, and T. Campos Jet Propulsion Laboratory, California Institute of Technology, CA, USA NASA Langley Research Center, CO, USA National Center for Atmospheric Research (NCAR), VA, USA Received: 28 August ...

Dispersion has been calculated for a fictitious scenario of an accidental Cs release in a nuclear power plant in Almaraz, Spain, with the Real-time On-line De-cisiOn Support system for nuclear emergencies, RODOS, and the FLEXPART lagrangian particle dispersion model coupled with the PSU/NCAR Mesoscale Model, MM5-V3.7-Flexpart (V6.2). Results show differences in the evolution of the radioactive ...