Typical Appearance In Vertical Cross Sections

A crowding of isentropes indicates an air mass boundary and a baroclinic zone. Though similar to fronts, the cloud band of the Baroclinic Boundary shows no front like appearance in a vertical cross section. The appearance is similar throughout all types of Baroclinic Boundary.

  • Isentropes (equivalent potential temperature):
    • Zone of high gradient of equivalent potential temperature, gradient mostly weaker than in fronts
    • Flat decline of crowded isentropes - a distinct difference from a front
    • Superadiabatic stratification only at low levels (associated with diabatic heating or cold air advection)
  • Divergence:
    • Zone of convergence within the highest gradient of isentropes, usually weaker than within a frontal zone
  • Vertical motion (Omega):
    • Upward motion within the gradient zone indicating ascent, but usually weaker than in a frontal zone
    • All cases show weak ascent at middle levels
19 October 2002/06.00 UTC - Meteosat IR image; position of vertical cross section indicated

 

Isentropes (equivalent potential temperature)

19 October 2002/06.00 UTC - Vertical cross section; black: isentropes (ThetaE), orange thin: IR pixel values, orange thick: WV pixel values

 

Divergence

19 October 2002/06.00 UTC - Vertical cross section; black: isentropes (ThetaE), magenta thin: divergence, magenta thick: convergence, orange thin: IR pixel values, orange thick: WV pixel values

 

Vertical motion (Omega)

19 October 2002/06.00 UTC - Vertical cross section; black: isentropes (ThetaE), cyan thick: vertical motion (omega) - upward motion, cyan thin: vertical motion (omega) - downward motion, orange thin: IR pixel values, orange thick: WV pixel values