Conveyor Belt Model

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Conveyor Belt Model

• EAS 211
• Spring 2005
• 02/28/05

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Conveyor Belt Model

• The conveyor belt model helps describe the 3D
  nature of the mid-latitude cyclone that the polar
  front theory neglects (3 belts).
• Conveyor belt modelthe modern description of the
  air flow through mid-latitude cyclone.

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Warm Conveyor Belt (WCB)

• Originates near the sfc in the warm sector of the
  ETC and flow toward and over the wedge of the
  warm front
• Warm belt flows up the frontal surface and cools
  adiabatically leading to condensation and precip
• As air rises it turns to the right and becomes
  incorporated into the westerly flow downwind of
  the upper-level trough

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Cold Conveyor Belt (CCB)

• Lies north of the warm front of the ETC
• Enter the storm at low-levels as an easterly
  belt, flowing westward toward the surface
  cyclone.
• Ascends as it flows, turns anticyclonically and
  becomes incorporated ino the upper-level westerly
  flow.
• Starts off cold and dry, but gains moisture form
  the evaporation of the raindrops falling from the
  WCB aloft

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Dry Conveyor Belt (DCB)

• Originates in the upper-troposphere as part of
  the generally westerly flow.
• Brings the coldest air into the cyclone
• Maintains the strong temperature contrast
  (gradient) across the cold front.
• Slowly descends from the NW behind the cold
  front, where it generally brings clearing
  weather.
• If a branch of this sweeps into the ETC, it
  produces a dry slot which looks like it appears
  to pinch off the comma head.

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