Small-Scale Variations in the Nocturnal Boundary Layer
Abstract
Boundary layers are often non-stationary due to small-scale propagating modes that includes wave-like motions, microfront, and more complex modes. Such small-scale motions (submeso) modulate the turbulent fluxes and modulate the local response of the boundary layer to surface heterogeneity and local terrain. In addition, the turbulence may not be able to maintain equilibrium with the non-turbulent flow. A case study of such nocturnal non-stationary flow over a shallow valley is presented where a mix of wave-like motions and microfronts modulate the valley cold pool and drainage flows. Additional case studies are prepared and a more systematic analysis of several networks of flux stations are carried out to examine systematic behavior of the small-scale motions and their difference between sites. Spatially-averaged fluxes are examined with implications for predicting "grid-averaged" fluxes in numerical models with emphasis on problems for low wind speeds.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A23D..02M
- Keywords:
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- 3307 Boundary layer processes;
- ATMOSPHERIC PROCESSES;
- 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSES;
- 3379 Turbulence;
- ATMOSPHERIC PROCESSES;
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES