In order to quantify the impacts of non-local processes on measured quantities in the local L-A system, modeling systems are required. Models can operate on different spatial and temporal scales and simulate processes from the micro-gamma to the meso-gamma scale and their respective interrelations, thus enabling a comprehensive analysis of the L-A system.
However, to derive robust results from such model simulations, it is of fundamental importance that the simulations are performed with different modeling systems, because every modeling systems is associated with uncertainties. Therefore, the LAFI simulations encompass the weather and climate models WRF and ICON, and the turbulence-resolving large-eddy simulation model PALM. These atmospheric models are coupled to different Land Surface Models in order to specifically consider the uncertainties associated with the interactions and exchange processes between the soil, the vegetation and the lowest part of the atmospheric boundary layer. These modeling systems form together the LAFI Multi Model Experiment (MME).
The nesting chain of the LAFI MME is shown in Fig. 1. The simulations for the outer model domain are conducted on the convection-permitting scale (1.25 km). In a first step, long-term simulations over the general observation period (GOP) in LAFI are performed with WRF-NoahMP and ICON on this domain. On top of this, additional WRF-NoahMP and ICON-LEM simulations are performed in a further increased spatial resolution for the LAFI intense observation periods (IOPs). Because of its high computational costs, PALM simulations are only performed for the IOPs.
Fig. 1: Nesting chain for the GOP (outer domain) and the IOPs (inner domains) for LAFO (upper row) and MOL-RAO (lower row).
By means of such a modeling strategy, it can be guaranteed that meso-scale atmospheric conditions are considered, and that local processes around the LAFI measurement sites are simulated in the required spatial and temporal resolution, for both, the IOPs and the GOP. Thus, a comparison of observations and model runs is guaranteed over the whole LAFI measurement period.
