A Collaborative Effort to Better Understand, Measure, and Model Atmospheric Exchange Processes over Mountains

Mathias W. Rotach , Stefano Serafin , Helen C. Ward , Marco Arpagaus , Ioana Colfescu , Joan Cuxart , Stephan F. J. de Wekker , Vanda Grubišic , Norbert Kalthoff , Thomas Karl , Daniel J. Kirshbaum , Manuela Lehner , Stephen Mobbs , Alexandre Paci (1) , Elisa Palazzi , Adriana Bailey , Jürg Schmidli , Christoph Wittmann , Georg Wohlfahrt , Dino Zardi

1 CNRM - Centre national de recherches météorologiques

In this essay, we highlight some challenges the atmospheric community is facing concerning adequate treatment of flows over mountains and their implications for numerical weather prediction (NWP), climate simulations, and impact modeling. With recent increases in computing power (and hence model resolution) numerical models start to face new limitations (such as numerical instability over steep terrain). At the same time there is a growing need for sufficiently reliable NWP model output to drive various impact models (for hydrology, air pollution, agriculture, etc.). The input information for these impact models is largely produced by the boundary layer (BL) parameterizations of NWP models. All known BL parameterizations assume flat and horizontally homogeneous surface conditions, and their performance and interaction with resolved flows is massively understudied over mountains-hence their output may be accidentally acceptable at best. We therefore advocate the systematic investigation of the so-called “mountain boundary layer” (MoBL), introduced to emphasize its many differences to the BL over flat and horizontally homogeneous terrain.

Domains: Sciences of the Universe [physics]

Mathias W. Rotach, Stefano Serafin, Helen C. Ward, Marco Arpagaus, Ioana Colfescu, et al.. A Collaborative Effort to Better Understand, Measure, and Model Atmospheric Exchange Processes over Mountains. Bulletin of the American Meteorological Society, 2022, 103, pp.E1282-E1295. ⟨10.1175/BAMS-D-21-0232.1⟩. ⟨insu-03863769⟩