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Article
Heat Transport by Turbulence and Submeso Structures in the Stable Boundary Layer
We examine measurements in the very stable boundary layer using tower data and a network of flux stations in the Shallow Cold Pool experiment. Submeso motions in the very stable boundary layer significantly mo...
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Article
Open AccessTypes of Vertical Structure of the Nocturnal Boundary Layer
The vertical structure of the observed stable boundary layer often deviates substantially from textbook profiles. Even over flat homogeneous surfaces, the turbulence may not be completely related to the surfac...
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Article
Open AccessHorizontal Variations of Nocturnal Temperature and Turbulence Over Microtopography
Nocturnal spatial variation of temperature, wind, and turbulence over microtopography is generally poorly understood. Low amplitude microtopography covers much of the Earth’s surface and, with very stable cond...
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Article
Small-Scale Spatial Variation of the Nocturnal Wind Field
This study examines the spatial variability of the nocturnal wind field using eight networks of surface observations ranging in horizontal width from 500 m to 65 km. The wind field is partitioned into small-sc...
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Article
Non-stationary Boundary Layers
The literature includes a wide variety of definitions or perceptions of non-stationarity. Non-stationarity can be expressed in terms of turbulence statistics or variability of the forcing of the turbulence suc...
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Article
Sea-Surface Stress Driven by Small-Scale Non-stationary Winds
A number of studies have indicated that non-stationarity of the wind field over the sea significantly disrupts the equilibrium between the wind, stress, and wave fields. However, no studies have systematically...
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Article
Open AccessSmall-Scale Variability in the Nocturnal Boundary Layer
Nocturnal variations of temperature and wind are examined at three contrasting sites. After the early evening period of rapid cooling, the magnitude of the variations of temperature on a time scale of 10 min t...
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Article
Near-Surface Vertical Flux Divergence in the Stable Boundary Layer
Flow in the stable boundary layer is examined at four contrasting sites with greater upwind surface roughness. The surface heterogeneity is disorganized and in some cases weak as commonly occurs. With low wind...
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Article
Directional Shear in the Nocturnal Atmospheric Surface Layer
We examine the potential importance of wind-directional shear in the surface layer of the stable nocturnal boundary layer by analyzing two tower datasets with eddy-correlation measurements at multiple levels. ...
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Article
Open AccessHeat Flux in the Strong-Wind Nocturnal Boundary Layer
Sonic anemometer measurements are analyzed from two primary field programs and 12 supplementary sites to examine the behaviour of the turbulent heat flux near the surface with high wind speeds in the nocturnal...
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Article
Stably Stratified Flow in a Shallow Valley
Stratified nocturnal flow above and within a small valley of approximately 12-m depth and a few hundred metres width is examined as a case study, based on a network of 20 sonic anemometers and a central 20-m t...
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Article
Edgar “Ed” L Andreas 1946–2015
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Article
Surface Stress with Non-stationary Weak Winds and Stable Stratification
The behaviour of turbulent transport in the weak-wind, stably-stratified, boundary layer over land is examined in terms of the non-stationarity of the wind field using measurements from three field programs. T...
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Article
Open AccessDependence of Turbulent Velocities on Wind Speed and Stratification
We examine the dependence of several turbulence quantities on the wind speed and stability using nocturnal data from the Shallow Cold Pool Experiment. The turbulent quantities (velocities) are defined in terms...
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Article
Heterogeneous Nocturnal Cooling in a Large Basin Under Very Stable Conditions
Large basins with relatively wide floors experience heterogeneous nocturnal cooling due to the diversity of the topography and the land use within the basin. Near mountain ranges the drainage flows prevail, bu...
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Article
Open AccessHorizontal diffusion by submeso motions in the stable boundary layer
Four networks of wind data are used to construct the first systematic estimates of the horizontal diffusivity from observations of submeso motions on scales often unresolved in numerical models. Currently, the...
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Article
The Influence of Transient Flow Distortion on Turbulence in Stable Weak-Wind Conditions
Transport by very weak turbulence near the surface, particularly with strong stratification, often violates existing similarity theory due partly to transient distortion of the wind profile by nonstationary me...
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Article
The influence of nonstationarity on the turbulent flux–gradient relationship for stable stratification
Extensive eddy-correlation datasets are analyzed to examine the influence of nonstationarity of the mean flow on the flux–gradient relationship near the surface. This nonstationarity is due to wavelike motions...
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Article
Observations of the cross-wind velocity variance in the stable boundary layer
Nine tower datasets over grassland, brush rangeland, snow covered plain, the ocean, three different pine forests, an aspen forest and an urban site, are used to document the scale-dependence of the cross-wind ...
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Chapter and Conference Paper
Mixing in Very Stable Conditions
Recent extensive observations of the nocturnal boundary layer, such as taken in CASES99 (Poulos et al., 2001) and SABLE98 (Cuxart et al., 2000), have revealed important deficiencies in our ability to model the...
