Some results about the relation between an objective front parameter and cloud bands in satellite images and its connection to classical cold front models

Abstract

Two different manifestations of cold fronts are compared: an objective front parameter (the thermal front parameter =TFP) which locates a front where the maximal change of the temperature (thickness) gradient appears and the cloud band in the satellite images. TheTFP is merely a line while the cloud band is mostly several hundred kilometers broad. The relation between the position of theTFP and the cloud band is investigated statistically using all cold front events of one year. It can be shown that theTFP prefers special positions relative to the cloud band and that these positions remain constant during the next 12 hours in a high number of cases. This confirms the usefulness of its diagnosis and very short range prognosis as is done with an operationally issued satellite report (Satrep). Vertical cross sections of equivalent potential temperature and humidity with some parameters superimposed show a connection between the position of theTFP relative to the cloud band and the classical cold front models of the ana-and katafront.