Definition of Mesoscale Meteorology

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Definition of Mesoscale Meteorology

• Term was coined by Lidga (51) in the compendium
  of meteorology (AMS)
• Lidga was a radar meteorologist
• Used the term to classify phenomena observed by
  radars that were not observed by conventional
  observations.
• Since then, a number of classification schemes
  have been proposed

From Orlanski (75, BAMS)
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Definition of Mesoscale Meteorology

• Fujita (81, JAS)

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The Challenge of Mesoscale Meteorology

• Check out the spectral analysis of observations
  from a weather station below
• Notice the following peaks
• Minutes turbulence
• 1 day diurnal oscillation
• A few days synoptic-scale motions
• Months planetary scale waves
• Notice the LACK of energy in the mesocale!!
  there is a spectral gap in the mesoscale
  spatial and time scales
• In other words, they were not being resolved! Is
  this true today?

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What is spectral analysis?

• Blue curve diurnal variation of wind speed
• Magenta curve synoptic variation of wind speed
• Yellow sum of diurnal and synoptic what you
  observe

• Take the observed yellow curve and decompose it
  into the blue and magenta curves.
• Then plot the amount of energy in each wave
  versus period of all waves observed

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• OK, lets check out this Definition of the
  Mesoscale module to finish our introduction
• http//www.meted.ucar.edu/mesoprim/mesodefn/index.
  htm (pgs 1 - 12)
• NOTES