LENS | Large Ensemble Community Project

The CESM Large Ensemble Project, led by Dr. Clara Deser (cdeser at ucar.edu) and Dr. Jennifer Kay (Jennifer.E.Kay at colorado.edu), is a publically available set of climate model simulations intended for advancing understanding of internal climate variability and climate change. All simulations are performed with the nominal 1-degree latitude/longitude version of the Community Earth System Model version 1 (CESM1) with CAM5.2 as its atmospheric component. The Large Ensemble Project includes a 40-member ensemble of fully-coupled CESM1 simulations for the period 1920-2100. Each member is subject to the same radiative forcing scenario (historical up to 2005 and RCP8.5 thereafter), but begins from a slightly different initial atmospheric state (created by randomly perturbing temperatures at the level of round-off error). The Large Ensemble Project also includes a set of multi-century control simulations with the atmosphere, slab-ocean, and fully-coupled versions of CESM1 under pre-industrial (1850) radiative forcing conditions (2600 years, 900 years and 1800 years in length, respectively). Details of all model simulations may be found in Kay et al. (2015). Directions for accessing the model output are available here. A full listing of monthly, daily, and 6-hourly outputs saved in “single variable” time series format is available here. Diagnostics for each simulation are available from the model component packages and the Climate Variability Diagnostics Package here.

When presenting results based on the CESM Large Ensemble in either oral or written form, please acknowledge the CESM Large Ensemble Community Project and supercomputing resources provided by NSF/CISL/Yellowstone, and reference Kay et al. (2015):

Kay, J. E., Deser, C., Phillips, A., Mai, A., Hannay, C., Strand, G., Arblaster, J., Bates, S., Danabasoglu, G., Edwards, J., Holland, M. Kushner, P., Lamarque, J.-F., Lawrence, D., Lindsay, K., Middleton, A., Munoz, E., Neale, R., Oleson, K., Polvani, L., and M. Vertenstein (2015), The Community Earth System Model (CESM) Large Ensemble Project: A Community Resource for Studying Climate Change in the Presence of Internal Climate Variability, Bulletin of the American Meteorological Society, doi: 10.1175/BAMS-D-13-00255.1, 96, 1333-1349. 

To see a list of papers or  projects using the CESM Large Ensemble click on Publications or On-going Project Descriptions. To add your research to the project listing please email Adam Phillips (asphilli at ucar.edu).

Additional non-technical description of the CESM Large Ensemble is available in Atmos News.