The atmospheric boundary layer is characterized by pervasive turbulent motions across diverse scales, driving the transport and mixing of crucial scalar quantities like temperature and water vapor (WV). Water vapor, a potent greenhouse gas, critically influences weather dynamics, radiative transfer, and numerical weather prediction (NWP). Its variability also introduces significant atmospheric artifacts in remote sensing techniques such as Interferometric Synthetic Aperture Radar (InSAR).

Understanding these WV fluctuations is thus essential not only for correcting measurement distortions in various applications but also for advancing climatological research. This work introduces the PALM model system, a high-resolution Large Eddy Simulation (LES) framework, as a novel tool in geodesy. LES models like PALM enable detailed and controlled simulations of the turbulent atmospheric boundary layer, capturing fine-scale dynamics unresolved by coarser atmospheric models.

To illustrate PALM's potential, we present a focused example: ray tracing within a PALM-simulated atmosphere to estimate the Zenith Wet Delay (ZWD), a critical parameter in GNSS-based positioning. We demonstrate that the spectrum of ZWD fluctuations derived from these simulations aligns well with theoretical predictions, highlighting PALM's capability for accurate turbulent atmospheric characterization.