TEMPERATURE ADVECTION

by ZAMG


There is a contribution to upward motion where:

This condition is fulfilled if

Therefore a contribution to upward motion exists in the maxima of warm advection (WA) which guides an evaluator to look for these maxima in a numerical temperature advection (TA) field.

Typical cloud configurations which are completely or partly connected with this parameter are:

In contrast, cold advection (CA) contributes to sinking motion and has, therefore, not so much importance in satellite image interpretation. Usually big areas of CA can be found in the areas of cellular cold air cloudiness behind fronts. CA represents the overall downward motion whilst the single cloud cells can be explained in connection with diabatic heat exchange (term 3 in the omega equation (compare Vertical Motion - Omega Equation ).

Some practical examples can be found in the test case from 11 February 1997/06.00 UTC.

11 February 1997/06.00 UTC - Meteosat IR image; SatRep overlay: names of conceptual models
11 February 1997/06.00 UTC - Meteosat IR image; blue: temperature 700 hPa
The following features should to be noted: It will be recalled from the omega equation that it is temperature advection, not temperature, that is the parameter responsible for the development of cloudiness. Therefore both parameters are superimposed on the next image.
11 February 1997/06.00 UTC - Meteosat IR image; blue: temparature 700 hPa, red dashed: temparature advection - CA 500/1000 hPa, red solid: temparature advection - WA 500/1000 hPa
Two aspects have to be considered when comparing the two parameters in relation to satellite imagery:

The following examples can be mentioned:


INDEX OF BASICS
VERTICAL MOTION - OMEGA EQUATION
VORTICITY