BAROCLINIC BOUNDARY - KEY PARAMETERS

• Height contours at 500 hPa:
  • Distribution of height at 500 hPa indicates boundary between closed synoptic systems:
  • To the rear of a trough
  • To the rear and in front of an ULL, in the tear - off stage of development
  • At the deformation zone between two troughs and two ridges
• Equivalent thickness:
  • A distinct gradient of equivalent thickness accompanies the cloud band
  • Mostly weaker than "classical" fronts
  • The appearance of this parameter is similar within all 3 types of Baroclinic Boundary
• Thermal front parameter (TFP):
  • Maximum of TFP associated with the cloud band
  • Normally, weaker than "classical" fronts
  • No significant propagation
  • The appearance of this parameter is similar within all 3 types of Baroclinic Boundary

Height contours at 500 hPa

1. At the rear of synoptic scale trough

   	19 October 2002/06.00 UTC - Meteosat IR image; cyan: height contours 500 hPa

2. Baroclinic boundary associated with ULL

   	05 February 2002/06.00 UTC - Meteosat IR image; cyan: height contours 500 hPa

3. Baroclinic Boundary associated with deformation zone at a saddle point of upper height Fields

   	04 April 2002/06.00 UTC - Meteosat IR image; cyan: height contours 500 hPa

Thermal front parameter (TFP) and equivalent thickness

	29 November 2002/12.00 UTC - Meteosat IR image; blue: thermal front parameter (TFP) 500/850 hPa, green: equivalent thickness 500/850 hPa