Questions tagged [planetary-boundary-layer]

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Can frictional force be un-aligned with wind direction?

There is a well known solution to Navier-Stokes equations for atmospheric boundary layer according to Ekman (see for instance PalArya's book "Introduction to Micrometeorology" or Holton's &...
MichaelW's user avatar
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1 vote
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Why shear stress vector must be parallel to flow in this example?

In the book by S. Pal Arya "Introduction to Micrometeorology" there is a chapter about Laminar Ekman Layers. I refer to the following example: Variables are: U, V wind velocity in x, y ...
MichaelW's user avatar
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Setting specific humidity vertical profile in an LES

I am working with an LES (Large-Eddy Simulation) model, and I want to define the vertical profile of specific humidity (qt) based on a given temperature profile (thl). However, I am not sure how to ...
bowserilis's user avatar
1 vote
1 answer
32 views

Question about planetary boundary (multichoice)

Why am I incorrect? Aerosols absorb energy right? (Click the image)
MERcurialKG's user avatar
5 votes
3 answers
347 views

Do surface temperature inversions only occur in valleys and natural bowls?

When you read about temperature inversions online, you mostly hear about them trapping pollution in places like Salt Lake City, which is surrounded by mountains. That seems to be the case for most ...
Empiromancer's user avatar
3 votes
1 answer
151 views

Question on the derivation of a prognostic equation for the mean concentration (Assume horizontal homogeneity in X)

In deriving the prognostic equation for the mean quantity of pollutant C, as shown in my solution below: Am I right in that I do not need to separate T (temperature) into its mean and turbulent parts ...
meteo_96's user avatar
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3 votes
1 answer
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Horizontal momentum flux in the surface layer

Given the question below, how would the kinematic momentum flux be at the surface layer? For letter a, why would it be that way (positive, negative, or 0)? Based on the answer below: I’m not sure if ...
meteo_96's user avatar
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2 votes
1 answer
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Recommendations for books on boundary layer Meteorology?

Does anybody have any recommendations on books tackling Boundary layer Meteorology? I've seen the book by Roland Stull and Arya, but are there any other more updated ones that are as good as these two?...
meteo_96's user avatar
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3 votes
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Is there a conceptual diurnal model for ozone profile?

So i know that there are diurnal patterns for virtual potential temperature that can be described conceptually (such as $\frac{\partial \theta_v}{\partial z}\approx 0$ in the mixed layer and $\frac{\...
BarocliniCplusplus's user avatar
5 votes
3 answers
13k views

Is it less windy in a valley than on a hill?

Assume we have a mountain landscape without trees. Would it be less windy in a valley than on a hill, or would the wind just be the same? Or in other words, which of the two images below describe ...
Adam's user avatar
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5 votes
0 answers
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What timescales do eddies operate at in the planetary boundary layer?

What are the largest eddies within the planetary boundary layer? What timescales do the operate on? Edit: I'm talking about atmospheric eddies over land. So, eddies that are measured in [eddy ...
naught101's user avatar
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6 votes
2 answers
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SST and air temperature differences

I'm trying to understand what causes the sea-surface temperature (in the open ocean and coastal areas) and the air temperature immediately above it to be different. I know very little about the ...
user4624937's user avatar
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12 votes
3 answers
424 views

Wind profile below the aerodynamic roughness length

The vertical profile of horizontal windspeed is often given by the so-called "log-law": $$u(z)=(u^*/k)\ln(z/z_0),\ \mathrm{for}\ z>z_0,$$ which can be found here. As can be seen from the ...
user4624937's user avatar
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18 votes
2 answers
8k views

What is the difference between roughness length and zero plane displacement?

Both roughness length $z_0$ and zero plane displacement $d$ seemed to be defined as the height above the ground at which wind speed theoretically becomes zero. But wind speed is also supposed to go to ...
environmentstudent's user avatar
10 votes
1 answer
123 views

Does within-canopy wind direction correlate with wind above the planetary bounday layer?

Wind above the planetary boundary layer (PBL) tends to be fairly smooth and constant over short periods of time. Below the planetary boundary layer, the smoothness is broken by eddies caused by ...
naught101's user avatar
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