Lagrangian Trajectories and Atmospheric Dispersion Modelling with LaMETTA in ICON

Abstract

The Lagrangian Model for Efficient Trajectory Transport in the Atmosphere (LaMETTA) is an on-line Lagrangian model system within the ICOsahedral Non-hydrostatic model system (ICON), implemented as a submodel in the Modular Earth Submodel System (MESSy) integrated framework. Such Lagrangian trajectory models are used for various scientific applications in atmospheric dynamics and chemistry. LaMETTA leverages the native spatial and temporal resolution of ICON, offering significant advantages over the off-line application relying on gridded output data with limited temporal resolution. LaMETTA is implemented based on an efficient inter-process communication and an optimized memory foortprint for application on highly parallelised computing systems. The parallel decomposition of the trajectories is derived from their geographical location and based on the parallel decomposition of the geographical grid used in ICON. In a first version the inter-process communication utilised parallel decomposition information directly from the driving model. With the implementation of MESSy as plugin in the ICON Community Interface (ComIn), these dependencies had to be removed. We present the updated Lagrangian model system, detailling on its parallelisation strategy based on the YAXT (Yet Another eXchange Tool) library and the improvements of parallel data output. Additionally, an outlook on the application of LaMETTA on regional scales, focusing on atmospheric dispersion modelling of wildfires will be given.