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Title: A spectral transform dynamical core option within the Community Atmosphere Model (CAM4)

A spectral transform dynamical core with an 85 spectral truncation resolution (T85) within the Community Atmosphere Model (CAM), version 4, is evaluated within the recently released Community Earth System Model, version 1.0 (CESM) global climate model. The spectral dynamical core option provides a well-known base within the climate model community from which to assess climate behavior and statistics, and its relative computational efficiency for smaller computing platforms allows it to be extended to perform climate length simulations using high-resolution configurations in the near term. To establish the characteristics of the CAM4 T85, an ensemble of simulations covering the present day observational period using forced sea surface temperatures and prescribed sea-ice extent are evaluated. Overall, the T85 ensemble attributes and biases are similar to a companion ensemble of simulations using the one degree finite volume (FV1) dynamical core, relative to observed and model derived datasets. Notable improvements with T85 compared to FV1 include the representation of wintertime Arctic sea level pressure and summer precipitation over the Western Indian subcontinent. The mean and spatial patterns of the land surface temperature trends over the AMIP period are generally well simulated with the T85 ensemble relative to observations, however the model is not ablemore » to capture the extent nor magnitude of changes in temperature extremes over the boreal summer, where the changes are most dramatic. Biases in the wintertime Arctic surface temperature and annual mean surface stress fields persist with T85 as with the CAM3 version of T85.« less
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  1. ORNL
  2. Scripps Institute of Oceanography
  3. National Center for Atmospheric Research (NCAR)
  4. Los Alamos National Laboratory (LANL)
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Advances in Modeling Earth Systems; Journal Volume: 6; Journal Issue: 3
Research Org:
Oak Ridge National Laboratory (ORNL); Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org:
SC USDOE - Office of Science (SC)
Country of Publication:
United States
climate modeling; spectral dycore; atmosphere model analysis