Scale‐Aware Evaluation of Complex Mountain Boundary Layer Flow From Observations and Simulations

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Titel: Scale‐Aware Evaluation of Complex Mountain Boundary Layer Flow From Observations and Simulations
Autoren: Karl Lapo, Anurag Dipankar, Brigitta Goger
Quelle: Geophysical Research Letters. 52
Verlagsinformationen: American Geophysical Union (AGU), 2025.
Publikationsjahr: 2025
Schlagwörter: model evaluation, complex boundary layer flow, Mesoscale modeling, Mountain meteorology, coherent spatiotemporal structures, multi-scale data diagnostics
Beschreibung: Boundary layers over complex, mountainous terrain are characterized by multi‐scale, complex flow structures, where the characterization of individual flow modes poses a fundamental challenge. We apply the novel multi‐resolution coherent spatio‐temporal scale separation (mrCOSTS) method to LIDAR observations and numerical data of the velocity components of complex mountain boundary‐layer flow. Using three distinct time scales (turbulent scales, mountain boundary layer, and diurnal scales) the underlying physical processes are explored. Furthermore, we identified the dominant flow patterns for each time scale, for example, down‐ and up‐valley flows, cross‐valley vortices, small‐scale turbulence, and large evening transition eddies. Applying mrCOSTS to simulated velocity components enables us to identify how coherent structures and the flow patterns are represented at various mesh sizes in the model. Using mrCOSTS we trivially retrieved complex dynamics that were previously difficult to resolve, enabling a direct, scale‐aware evaluation between the LIDAR observations and model results.
Publikationsart: Article
Sprache: English
ISSN: 1944-8007
0094-8276
DOI: 10.1029/2025gl116441
DOI: 10.3929/ethz-c-000784332
Rights: CC BY
Dokumentencode: edsair.doi.dedup.....c6e4b09ed6ede5453c77d9594049c80c
Datenbank: OpenAIRE
Beschreibung
Abstract:Boundary layers over complex, mountainous terrain are characterized by multi‐scale, complex flow structures, where the characterization of individual flow modes poses a fundamental challenge. We apply the novel multi‐resolution coherent spatio‐temporal scale separation (mrCOSTS) method to LIDAR observations and numerical data of the velocity components of complex mountain boundary‐layer flow. Using three distinct time scales (turbulent scales, mountain boundary layer, and diurnal scales) the underlying physical processes are explored. Furthermore, we identified the dominant flow patterns for each time scale, for example, down‐ and up‐valley flows, cross‐valley vortices, small‐scale turbulence, and large evening transition eddies. Applying mrCOSTS to simulated velocity components enables us to identify how coherent structures and the flow patterns are represented at various mesh sizes in the model. Using mrCOSTS we trivially retrieved complex dynamics that were previously difficult to resolve, enabling a direct, scale‐aware evaluation between the LIDAR observations and model results.
ISSN:19448007
00948276
DOI:10.1029/2025gl116441