Warm and Cold Advection Generated by Short Waves at Mid Levels

  • consider a long wave trough over a stationary front (a). Then, a short wave moves into the trough, intensifying the trough (b)
  • Notice that initially (a), the streamlines and isotherms are parallel to each other - the atmosphere is barotropic
  • In (b), the short wave has acted to cause the streamlines to cross the isotherms both west and east of the trough. The atmosphere there is now "baroclinic".
  • In the baroclinic region west of the trough, cold-air advection is occurring
  • In the baroclinic region east of the trough, warm-air advection is occurring 
  • Cold-air advection west of the trough will produce sinking motion as the cold air descends to the surface behind the cold front
  • Warm-air advection east of the trough will produce rising motion near the center of the low as the warm air ascends.
  • This sinking and rising of cold and warm air due to cold and warm air advection is called baroclinic instability
  • Baroclinic instability is a necessary ingredient for the development and intensification of a mid-latitude cyclone. - check out this real-world example
  • The sinking and rising of warm air produced by baroclinic instability can also be visualized by the warm- and cold-conveyor belt model











What is Temperature Advection?