Community Earth System Model Large Ensemble (CESM LENS)

atmosphere climate climate model geospatial ice land machine learning model oceans sustainability zarr


The Community Earth System Model (CESM) Large Ensemble Numerical Simulation (LENS) dataset includes a 40-member ensemble of climate simulations for the period 1920-2100 using historical data (1920-2005) or assuming the RCP8.5 greenhouse gas concentration scenario (2006-2100), as well as longer control runs based on pre-industrial conditions. The data comprise both surface (2D) and volumetric (3D) variables in the atmosphere, ocean, land, and ice domains. The total data volume of the original dataset is ~500TB, which has traditionally been stored as ~150,000 individual CF/NetCDF files on disk or magnetic tape made available through the NCAR Climate Data Gateway for download or via web services. NCAR has copied a subset (currently ~70 TB) of CESM LENS data to Amazon S3 as part of the AWS Public Datasets Program. To optimize for large-scale analytics we have represented the data as ~275 Zarr stores format accessible through the Python Xarray library. Each Zarr store contains a single physical variable for a given model run type and temporal frequency (monthly, daily, 6-hourly).

Update Frequency

Rare. The LENS experiment is complete, but we may occasionally copy additional fields from NCAR to AWS, or fix problems discovered in the AWS copy.



Managed By

See all datasets managed by National Center for Atmospheric Research.


How to Cite

Community Earth System Model Large Ensemble (CESM LENS) was accessed on DATE from

Usage Examples

Tools & Applications

Resources on AWS

  • Description
    Project data files
    Resource type
    S3 Bucket
    Amazon Resource Name (ARN)
    AWS Region
    AWS CLI Access (No AWS account required)
    aws s3 ls s3://ncar-cesm-lens/ --no-sign-request

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