Absolute Instability

  • consider the diagram to the right, notice that at 2 km (or anywhere for that matter):

  • Tsp > Tup > Te

  • Hence, an unsaturated or saturated parcel will always be warmer than the environment and will continue to ascend

  • This is an example of absolute instability

  • The condition for absolute instability is:

    • Ge>Gd>Gm

  • Ge is the environmental lapse rate (30C km-1)
  • Gd is the dry adiabatic lapse rate (10C km-1)
  • Gm is the moist adiabatic lapse rate (6C km-1)