Typical Appearance In Vertical Cross Sections

  • Isentropes:
    Isentropes show mainly frontal character. No impact from Upper Wave
  • Temperature Advection:
    Maximum at 300 hPa or at higher levels, connected to tropopause folding (related to potential vorticity), cold advection below the Wave bulge at lower levels
  • Vorticity Advection:
    Significant maximum of positive vorticity advection at upper levels connected to the sharpening of the upper level trough at 300 hPa
  • Vertical motion:
    Vertical motion indicates rising air, with the maximum at upper levels, due to a rising upper relative stream
22 August 2005/12.00 UTC - Meteosat 8 IR 10.8 image; position of vertical cross section indicated

 

Temperature Advection

22 August 2005/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), red thin: temperature advection - CA, red thick: temperature advection - WA, orange thin: IR pixel values, orange thick: WV pixel values

 

Vorticity Advection

22 August 2005/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), green thin: vorticity advection - NVA, green thick: vorticity advection - PVA, orange thin: IR pixel values, orange thick: WV pixel values

 

Vertical Motion

22 August 2005/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), cyan: vertical motion (omega) - upward motion, orange thin: IR pixel values, orange thick: WV pixel values

 

Potential Vorticity

22 August 2005/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), dark green thin: potential vorticity <1 unit, dark green thick: potential vorticity >=1 unit, orange thin: IR pixel values, orange thick: WV pixel values

 

Distinction between Wave and Upper Wave according to vertical cross sections


Upper Wave Wave
TA indicates a CF in CA, CA dominates WA dominates at all levels in the area of cloud band
Intense PV sinking only down to 400 hPa, PV=0.8 units below 500 hPa, no significant PV at lower levels PV = 1 down at middle and low levels, interaction with upper levels
Maximum of upward motion at higher levels Strong upward motion throughout the low and mid levels of the troposphere

Below left is the case of an Upper Wave, below right is the case of a Wave (2nd row below left shows vertical cross section over Wave bulge). While the Upper Wave has no separate maximum of PV>=1 unit at low levels, the Wave case from the 4 July 2005/12.00 UTC shows a distinct maximum at low levels, which is usually more intense and can exceed PV>=2 units.

22 August 2005/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), dark green thin: potential vorticity <1 unit, dark green thick: potential vorticity >=1 unit, orange thin: IR pixel values, orange thick: WV pixel values
04 July 2005/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), dark green thin: potential vorticity <1 unit, dark green thick: potential vorticity >=1 unit, orange thin: IR pixel values, orange thick: WV pixel values
04 July 2005/12.00 UTC - Meteosat 8 IR 10.8 image; position of vertical cross section indicated