Check Out New LASSO-ENA Simulations and Web Tools

Published: 24 November 2025

Editor’s note: William Gustafson, principal investigator for the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) activity, provided the following blog post.

The LASSO team recently held a virtual information session to share new simulations and tools available for the most recent LASSO scenario, which focuses on ARM’s Eastern North Atlantic (ENA) atmospheric observatory. The LASSO-ENA scenario contains a series of LES cloud simulations of shallow marine clouds for 64 case dates spread between 2015 and 2022. These simulations are a great foundational set of simulations complementing ARM’s observations to help researchers do their science.

LASSO-ENA Web Tools and Simulations

During the information session, we announced the new LASSO-ENA Bundle Browser, which makes reviewing and downloading LASSO-ENA simulation data quick and easy. And, to help researchers understand what is available, the complementary LASSO-ENA Technical Document is now online too. As described during the session, these two tools provide a lot of detail about what was observed for each case combined with how each simulation compares with the observations. Check out the recording of the information session to learn more, if you missed it.

The browser and technical document will continue to evolve as we release more of the LASSO-ENA scenario. In the browser as I write this blog post are a core set of simulations from the System for Atmospheric Modeling (SAM) LES model that use spectral-bin microphysics to simulate the clouds. Each case date includes an ensemble consisting of two different input data sets for the large-scale forcing—the European Centre for Medium-Range Weather Forecasts Reanalysis version 5 (ERA5) and the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2)—combined with three options for the background aerosol number concentration.

Additional simulations are running on ARM’s high performance computing cluster that will provide a choice of forcing scale used to generate the large-scale forcing. These, along with simulations for various sensitivity comparisons and simulations using bulk microphysics, will be posted to the browser once they are reviewed and post-processed for archiving. The online technical document is designed as a living document that will also be updated over time to stay consistent with newly available simulations.

The recording of the LASSO-ENA information session is available in ARM’s document repository along with a PDF file of the presentation slides and a PowerPoint (.pptx) version of the slides with plot animations. Check them out for more details. Please note that the PowerPoint slides should be downloaded (choose “Download Original” in the Download dropdown menu) to view the animated slide content.

You can also contact the LASSO team at lasso@arm.gov with questions and to get help with accessing the simulations. We love to hear from users and help you optimally use our products.

LASSO-BNF Information Session

In closing, I draw your attention to another LASSO information session coming up at 4 p.m. Eastern on Tuesday, December 2, to talk about our next LASSO scenario, which will focus on ARM’s Bankhead National Forest (BNF) observatory in Alabama. This LASSO-BNF information session will be a discussion format to collect community needs, gauge interest in possible simulation approaches for the BNF, and a time for you to influence what LASSO-BNF will become. Please join us by registering to attend.

We have also created a survey in support of this information session. Please complete our LASSO-BNF survey to help us understand what the community would like from a LASSO-BNF scenario.