PALM

PALM is a large-eddy simulation (LES) model for atmospheric and oceanic boundary-layer flows, developed mainly at the Institute of Meteorology and Climatology of Leibniz Universität Hannover. It is written in Fortran, parallelized with MPI, uses NetCDF for input and output, and is distributed as free software (GPLv3). Instead of parametrizing boundary-layer turbulence as a mesoscale model such as WRF does, PALM resolves the large eddies explicitly, which makes it suitable for simulations at the scale of meters. PALM-4U (PALM for urban applications) is the set of components that extend the model to cities: buildings are resolved explicitly on the grid, and dedicated modules handle the urban surface energy balance (urban surface model), soil and vegetation (land surface model), 3D shading and reflections between buildings (radiative transfer model), trees (plant canopy model) and human thermal comfort indices (biometeorology), among others. A PALM-4U simulation takes a static driver (a NetCDF file describing terrain, buildings, vegetation and surface types) and, optionally, a dynamic driver with boundary conditions taken from a larger-scale model, typically WRF. For a general description of the model system see Maronga et al. (2020), linked at the end.

This page describes how PALM 24.04 was compiled and run on Hydra (PBS, queue larga), including the problems found along the way. It was tested between late June and early July 2026. Wherever you see <user>, use your own Hydra username.