In May 2015, the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility began a pilot project to design a routine, high-resolution modeling capability to complement ARM’s extensive suite of measurements at the Southern Great Plains megasite. This large-eddy simulation (LES) modeling capability has been named LASSO—the LES ARM Symbiotic Simulation and Observation workflow.

The Alpha 1 release is the first dissemination of simulations and analysis tools from LASSO for five shallow convection cases, occurring roughly one year into the pilot project life cycle, and is in the form of an ARM evaluation product. This release serves as a high-level interface to the data files, collectively called data bundles, which consist of:

• LES input and outputs
• ARM observations co-registered on the model grid, model diagnostics, and skill scores
• Quicklooks of various fields.

An interface is provided to a web browsing tool, called the LASSO Bundle Browser, for users to find simulations of interest through examination of the LES performance relative to select ARM observations. See the LASSO Alpha 1 release documentation for details on the contents of the data release and the bundle browser.

This release contains a battery of simulations and model-observation comparisons for different LES models, large-scale forcings, model configurations, and preliminary observational products that the LASSO team are using to assess workflow options for use in operations. Simulations from both the System for Atmospheric Modeling (SAM) and the Weather Research and Forecasting (WRF) model are available.

A range of forcings are under consideration for use with LASSO combined with the sensitivity of model simulations to model selection and physics options. Many of the simulations are directly comparable, e.g., they use the same model configuration and only differ in the forcing or initial conditions used to drive the model. Other simulations differ in the particular choice of microphysics. The release also serves as an initial introduction to the skill scores being designed for model evaluation.

Note that the simulations within this release represent the typical behavior to be expected from LES using best-practice configurations and are valid for use in various research applications. However, as made evident by the comparisons to observations, there is a range of model behavior so we recommend that users contact the LASSO team to ensure the details of the simulations are understood and that they are used appropriately for their application.

An objective for the Alpha 1 release is to solicit feedback from the community. Efforts to improve the model configuration, forcings, and analysis tools are ongoing and will evolve over the coming year based on user feedback and continued effort. We encourage users to explore the available simulations and tools and to share their experience and ideas for improvement with the LASSO team.

For questions or to report data problems, please contact William Gustafson or Andy Vogelmann. To access the data bundles, please browse the ARM Data Archive. (Go here to create an account to download the data.)

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The ARM Climate Research Facility is a national scientific user facility funded through the U.S. Department of Energy’s Office of Science. The ARM Facility is operated by nine Department of Energy national laboratories.