Boundar Layer Meteorology Lecture 2

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Boundar Layer Meteorology Lecture 2

• Review chapter 1 of Garratt
• Terminology and Notation Review
• Some non-dimensional numbers
• Reynolds Averaging

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Review chapter 1 of Garratt

• Inner and outer layers (whats with this, is the
  outer layer really part of the boundary layer?)
• Seasonal and geographic variations of the
  boundary layers character.

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Modeled Boundary Layer Depth
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Modeled Boundary Layer Depth
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Observed Boundary Layer Depth
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Terminology

• Boundary Layer Regions
• Surface Layer
• Mixed Layer
• Residual Layer
• Stable (Nocturnal Boundary) Layer
• Entrainment Zone
• Ekman Layer (Outer Layer)
• Surface Layer

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Boundary Layer Regions
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Notation

• Variables T, Tv ,?, ?v , ?, q, x, y, z,
• Viscosity ? ???du/dy? ??????T?????????kg/(m
  s)Pa/s?
• Kinetmatic viscosity ????????????????m2/s
• Summation (Einstein) notation see Stull handout
  (pp. 57-74). Note definitions of the Kronecker
  delta (and distinction between it and the unit
  vector), and the alternating unit tensor
  (Levi-Civita symbol) used to express the cross
  product.

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Some Non-Dimensional Numbers

• Reynolds number Re VL/?
• Reynolds number is ratio of acceleration (or
  inertial force) to friction force. It governs
  transition to turbulence (at high Reynolds
  numbers , e.g. about 2300 for pipes highly
  variable!).
• Richardson numbers ratio of
• Flux
• Gradient Ri (g/???d??dz)/(du/dz)2
• Bulk

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Reynolds averaging and Reynolds Stresses
t1 should be enough larger than t2 so that the
average is independent of time.
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Reynolds averaging and Reynolds Stresses
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Understanding Reynolds Stress