Reference LES Simulations for Ocean Models Validation

All Large-Eddy Simulations (LES) computations are conducted with the open-source PALM solver (https://palm.muk.uni-hannover.de/trac) and version 5.0 of the Los Alamos National Laboratory (https://github.com/lanl/palm_lanl) branch. The simulations use a cubical domain with length L=128m, three grid resolutions (N=1283, 2563, or 5123), and mimic four single-column canonical oceanic regimes in which the surface flux and background stratification profiles are imposed. These simulations are named cooling (c), stratification (s), evaporation (e), and mixed (m):

cooling cases test different surface heat fluxes: Qh=-1.185x10-5 (c01), -2.371x10-5 (c02), -4.742x10-5 (c04), and -18.966x10-5 (c16) [K.m/s]. The background stratification is set through a vertical temperature gradient (Tz) equal to 0.1 [K/m], and both the salinity surface flux (Qs) and the background stratification due to vertical salinity gradient (Sz) are equal to zero.

stratification cases are similar to the cooling c02 case, but Qh=-2.371x10-5 [K.m/s], and Tz=0.01 (s01), 0.1 (s10), or 0.2 (s20) [K/m].

evaporation cases define Qh=Tz=0, Sz=-0.025 [PSU/m], and Qs=3.115x10-6 (e01) or 1.225x10-5 (e04) [PSU/(m2.s)].

mixed cases combine heat and salinity surface fluxes, and the background stratification is imposed by both vertical temperature and salinity gradients. There are four mixed cases in which Qh=-1.185x10-6 [K.m/s], Tz=0.05 [K/m], Sz=-0.025 [PSU/m], and Qs is either 0 (m01), 3.115x10-6 (m02), 9.10x10-6 (m03), or 4.55x10-5 (m04) [PSU/(m2.s)].

The simulations run 96h at a latitude of  43.29o, and utilize a linear equation of state where the reference temperature and salinity are 293.15 K and 35 PSU. The subgrid turbulent scales are modeled through the Moeng and Wyngaard SGS closure (see PALM documentation), and the flow is perturbed during the first 150 s of simulation with normally distributed fluctuations with a maximum amplitude of 10-4. The dataset provides 1D and 3D statistics. The 1D profiles are time-averaged during 3600 s and written every 3600 s. The 3D fields are not time-averaged and written every 3600 s, except those obtained with the grid having 5123 points. In this case, the data are written every 21,600 s. The 3D fields are not in the tar file but can be requested by emailing the authors ([e-mail]). The PALM input decks of the simulations are included in the shared files.

Note: the PALM version used in this work requires the 1D salinity flux profiles to be normalized by the product of Nx and Ny (number of grid points in x and y)

LA-UR-22-32996