PALM is an advanced and state-of-the-art meteorological modeling system for atmospheric and oceanic boundary layer flows.

It was developed as a turbulence-resolving large-eddy simulation (LES) model specifically designed to run on massively parallel computer architectures. Meanwhile, turbulence closure based on the Reynolds-averaged Navier-Stokes (RANS) equations has been added so that PALM can run not only in turbulence-resolving mode (i.e., LES) but also in RANS mode, in which the entire turbulence spectrum is parameterized.

Due to the extensive extensions to the model, PALM is no longer an abbreviation, but rather the name in its own right. It describes the PALM model system, which consists of the PALM model core and the PALM-4U components.

more information can be found on the official PALM website