The Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) datastream is now produced in an ongoing manner given the completion of the two-year pilot phase. After each shallow convection season ends at the Southern Great Plains atmospheric observatory, a set of data bundles are produced.

Bundles for 2015 and 2016 were produced as part of the pilot phase and are preliminary versions of the final product. The Alpha 1 and Alpha 2 bundles serve the purpose of demonstrating the overall LASSO concept to researchers, providing a means for facilitating community discussion and feedback, and making available initial sets of simulations and accompanying observations for research purposes. From 2017 onward, a standardized model configuration and data bundle format has been chosen that is anticipated to be stable. A history of releases and differences between them can be found in the LASSO change log.

Each release is a collection of data files, which entails a collection of what ARM calls “data bundles,” which consists of:

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

For routine operations, simulations from the Weather Research and Forecasting (WRF) model are available that have been driven using a range of forcings. This selection of forcings forms an ensemble that increases the likelihood of obtaining realistic LES simulations.

More complete details about the LES configuration and data included in the bundles are available in the Description of the LASSO Data Bundles Product.

The simulations within LASSO represent the typical behavior expected from LES using best practice configurations and are valid for use in various research applications. We recommend users contact the LASSO team to ensure the details of the simulations are understood and that the simulations are used appropriately for a given application.

LASSO Bundle Browser

The Bundle Browser interface has been designed to help users find simulations of relevance for their needs. The browser is a tool based on the Cassandra NoSQL database methodology that permits search by value queries of the skill scores and dynamically creates data plots or “quicklooks” of selected simulations for selected metrics.

The Bundle Browser returns results for the operational and Alpha 2 shallow convection cases and is the easiest method for accessing the data bundles. See the Description of the LASSO Data Bundles Product for details on the browser.

LASSO Alpha Products

The LASSO pilot phase produced two sets of “alpha” releases. In addition to the large-scale forcing ensemble, the alpha releases include sensitivity tests for multiple configuration choices, such as domain size, grid spacing, model selection, and microphysics choice.

When using Alpha 1 results, note that Alpha 2 corrected some deficiencies in Alpha 1. To make the 2015 cases available, a selection of the Alpha 1 simulations have been reprocessed using Alpha 2 code and included as a supplemental release to Alpha 2.

Looking for Feedback

Even though the LASSO pilot phase has completed, efforts are ongoing to improve the model configuration, forcings, and analysis tools. These will evolve 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 at Users may also contact William Gustafson, lead principal investigator or Andrew Vogelmann, co-principal investigator, directly.