Typical Appearance In Vertical Cross Sections

  • Isentropes:
    ECs and Cb clusters exist within an unstable airmass. This can be observed in the cross section by decreasing values of isentropes with height within lower and mid-levels of the troposphere (usually between surface and 700 hPa).
  • Relative humidity:
    There are high values of relative humidity within the lower and mid-levels of the troposphere. In the layer between 1000 - 700 hPa, a humidity maximum can often be observed. The relative humidity isolines show a maximum (90-100%) near the surface, but also relative maxima higher in the atmosphere in the vicinity of the clusters.
  • Divergence:
    The field of divergence shows convergence within lower and mid-levels in the area of the EC and divergence above.
  • Vorticity advection:
    The field of vorticity advection is characterised by maxima generally at higher levels of the atmosphere. A maximum can often be observed between 500 and 300 hPa.
  • Vertical motion:
    A maximum of vertical velocity is found in the layer between 700 and 600 hPa.

24 April 2008/12.00 UTC - Meteosat 9 IR10.8 image; position of vertical cross section indicated
13 January 2008/18.00 UTC - Meteosat 9 IR10.8 image; position of vertical cross section indicated

Isentropes

24 April 2008/12.00 UTC - Vertical cross section; black: isentropes (ThetaE)
13 January 2008/18.00 UTC - Vertical cross section; black: isentropes (ThetaE)

Relative Humidity

24 April 2008/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), blue: relative humidity
13 January 2008/18.00 UTC - Vertical cross section; black: isentropes (ThetaE), blue: relative humidity

Divergence

24 April 2008/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), magenta thin: divergence, magenta thick: convergence
13 January 2008/18.00 UTC - Vertical cross section; black: isentropes (ThetaE), magenta thin: divergence, magenta thick: convergence

Vorticity Advection

24 April 2008/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), green: vorticity advection
13 January 2008/18 UTC - Vertical cross section; black: isentropes (ThetaE), green: vorticity advection

Vertical Motion

24 April 2008/12.00 UTC - Vertical cross section; black: isentropes (ThetaE), cyan thick: vertical motion (omega) - upward motion, cyan thin: vertical motion (omega) - downward motion
13 January 2008/18.00 UTC - Vertical cross section; black: isentropes (ThetaE), cyan thick: vertical motion (omega) - upward motion, cyan thin: vertical motion (omega) - downward motion