Simulation Ensembles

LASSO-ENA uses ensembles of simulations for each case date to provide information on background meteorological conditions, particular model physics options, and domain configurations. The details around the choices are described in the Modeling Configuration portion of the documentation. Generally, each case date has a core set of twelve ensemble members based on permutations of the input datasets (ERA5 and MERRA-2), the input sampling region (1° or 5° box) and three background aerosol concentrations (low, medium, and high). A portion of the cases have additional simulations based on toggling cloud-ice processes, using a wider or taller domain, etc.

LASSO uses combinations “input dataset,” “domain,” and “configuration” labels to identify unique simulation configurations. These map to the simulation filenames as described in File Descriptions. The currently available options for each of these labels are shown in Table 8, Table 9, and Table 10. Not every permutation is available and too many combinations are available to list individually. To clarify the most commonly available simulations, labels in red are included in the core ensemble.

Table 8 Input dataset labels associated with the available LASSO-ENA ensemble members. Red values indicate core ensemble parameter options.

Label Type	Label Value	Description
Input Data	era5	Forcing source: ERA5; Forcing scale: 5°, Nudging: Default (only winds)
Input Data	merra2	Forcing source: MERRA-2; Forcing scale: 5°, Nudging: Default (only winds)
Input Data	era5s1n0	Forcing source: ERA5; Forcing scale: 1°, Nudging: Default (only winds)
Input Data	merra2s1n0	Forcing source: MERRA-2; Forcing scale: 1°, Nudging: Default (only winds)
Input Data	era5s5n1	Forcing source: ERA5; Forcing scale: 5°, Nudging: T & Qv nudged above inversion top to the model top; U & V nudged for entire profile
Input Data	era5s1n1	Forcing source: ERA5; Forcing scale: 1°, Nudging: T & Qv nudged above inversion top to the model top; U & V nudged for entire profile
Input Data	era5s5n2	Forcing source: ERA5; Forcing scale: 5°, Nudging: T & Qv nudged above 2 km; U & V nudged for entire profile
Input Data	era5s1n2	Forcing source: ERA5; Forcing scale: 1°, Nudging: T & Qv nudged above 2 km; U & V nudged for entire profile

Table 9 Domain labels associated with the available LASSO-ENA ensemble members. Red values indicate core ensemble parameter options.

Label Type	Label Value	Description
Domain	25x100	Domain width: 25 km; Horizontal grid spacing: 100 m; Domain top: 8 km
Domain	25x100tall	Domain width: 25 km; Horizontal grid spacing: 100 m; Domain top: 13 km
Domain	102x100	Domain width: 102 km; Horizontal grid spacing: 100 m; Domain top: 8 km

Table 10 Input dataset labels associated with the available LASSO-ENA ensemble members. Red values indicate core ensemble parameter options.

Label Type	Label Value	Description
Configuration	sbmwrm-aer1-flxsst	Microphysics: warm-phase SBM; Background aerosol: low; Surface flux: Specified SST
Configuration	sbmwrm-aer2-flxsst	Microphysics: warm-phase SBM; Background aerosol: medium; Surface flux: Specified SST
Configuration	sbmwrm-aer3-flxsst	Microphysics: warm-phase SBM; Background aerosol: high; Surface flux: Specified SST
Configuration	sbmice-aer1-flxsst	Microphysics: SBM with ice phase; Background aerosol: low; Surface flux: Specified SST
Configuration	sbmice-aer2-flxsst	Microphysics: SBM with ice phase; Background aerosol: medium; Surface flux: Specified SST
Configuration	sbmice-aer3-flxsst	Microphysics: SBM with ice phase; Background aerosol: high; Surface flux: Specified SST
Configuration	morr-aer1-flxsst	Microphysics: Morrison; Background aerosol: low; Surface flux: Specified SST
Configuration	morr-aer2-flxsst	Microphysics: Morrison; Background aerosol: medium; Surface flux: Specified SST
Configuration	morr-aer3-flxsst	Microphysics: Morrison; Background aerosol: high; Surface flux: Specified SST

List of Simulations

A complete list of simulations is extensive given the permutation of case dates, core ensemble, and supplementary configuration ensemble members. Currently, 1766 simulations are available for download from the LASSO-ENA Browser. The full list of available simulations is provided in a CSV file, which will be updated as new simulations are released.

General groupings of simulations will be of interest for particular applications. The “core ensemble” contains simulations using warm-phase spectral-bin microphysics and explores both sensitivity to input data sets and aerosol concentrations. This is complemented by additional simulations from the “ice-phase ensemble” that identifies impacts of ice processes for a subset of case dates. Alternatively, simulations for the “Morrison ensemble” show the impact of using the more detailed spectral-bin microphysics versus the more commonly used bulk microphysics. Users interested in mesoscale structure will benefit form the large-domain simulations that explore whether the domain size impacts cloud characteristics for select cases.