CESM2 Decadal Prediction (DP) Reforecasts

The CESM2 DP (Decadal Prediction) dataset is an initialized prediction system using CESM2. It consists of fully coupled initialized hindcast simulations using CESM2 component models at nominal 1 degree horizontal resolution. Hindcasts are initialized on November 1st from historical reconstructions (SMYLE-FOSI for ocean and sea-ice; Forced-land only for land; and JRA55 reanalysis for atmosphere) and then integrated forward 122-months. Initialization occurs each year between 1958-2023. The ensemble size is 20 for each start date, with ensemble spread introduced through a random field perturbation applied to the atmospheric initial conditions. The CESM2 DP dataset is the decadal extension of November initializations of CESM2 SMYLE (DOI: 10.26024/PWMA-RE41).

CESM2-DP at a glance

  • CESM2 model: ocean (POP2, 1°, 60L); atmosphere (CAM6-FV, 1°, 32L); land (CLM5); sea ice (CICE5); ocean biogeochemistry (MARBL)
  • Hindcasts initialized on the 1st of November from 1958 to 2023
  • 122-month simulations
  • 20-member ensembles
  • CAM6 initialization: JRA55 Reanalysis
  • POP2 initialization: JRA55-do forced ocean/sea-ice (FOSI) simulation
  • CICE5 initialization: JRA55-do forced ocean/sea-ice (FOSI) simulation
  • CLM5 initialization: CRU-JRAv2 forced land simulation
  • Data availability on Geoscience Data Exchange & DOI: https://gdex.ucar.edu/datasets/d651082/
  • Data availability on NCAR’s campaign storage system (accessible from Casper): /glade/campaign/cesm/development/espwg/CESM2-DP/

Reproducing SMYLE (the first two years of CESM2-DP)

  • SMYLE was run in 2021 on the Cheyenne system at the NCAR-Wyoming Supercomputing Center. Bit-for-bit reproducibility may not be possible!
  • SMYLE was run using the following special tag of CESM2: cesm2.1.4-SMYLE. Code modifications for SMYLE have since been merged onto the main CESM2.1 trunk.
  • Restart files used for initializing SMYLE hindcasts are on NCAR’s campaign storage system (accessible from Casper): /glade/campaign/cesm/development/espwg/SMYLE/inputdata/cesm2_init/

The following paper documents the SMYLE experimental design and provides a broad overview of system skill:

Yeager, S. G., N. Rosenbloom, S. Glanville, X. Wu, I. Simpson, H. Li, M. J. Molina, K. Krumhardt, S. Mogen, K. Lindsay, D. Lombardozzi, W. Wieder, W. M. Kim, J. H. Richter, M. Long, G. Danabasoglu, D. Bailey, M. Holland, N. Lovenduski, W. G. Strand, and T. King (2022): The Seasonal-to-Multiyear Large Ensemble (SMYLE) prediction system using the Community Earth System Model Version 2, Geosci. Mod. Dev., 15, 6451-6493, https://doi.org/10.5194/gmd-15-6451-2022

Contacts

Acknowledging Use of CESM2-DP Data

CESM2-DP data are available for download at https://gdex.ucar.edu/datasets/d651082/ and can also be directly accessed for analysis on CISL’s Casper cluster (/glade/campaign/cesm/development/espwg/CESM2-DP/). Please add your name to the SMYLE analysis registry to help us track who is using this resource. We request that you cite both the data DOI (https://gdex.ucar.edu/datasets/d651082/) as well as the dataset description paper (Yeager et al. 2022) in work that makes use of SMYLE. Finally, we welcome collaboration and information sharing, so please consider joining the CESM Earth System Prediction Working Group and presenting your work at upcoming ESPWG meetings.