No notable difference could be found in the configuration of NWP parameters within vertical cross sections between Warm Conveyor Belt Occlusion and Cold Conveyor Belt Type.

The isentropes of the equivalent potential temperature generally show a distinct trough structure indicating the warmer air which has been lifted (see Meteorological physical background ) and the crowding zone of a surface front. In this case the upper level trough is forward inclined with height. The most frequent configuration is a Warm Front inclined crowding zone in front of the isentropic trough structure. The difference between the cross section of an Occlusion cloud band and of a Warm Front cloud band can be seen in the layer above the Warm Front surface: in a Warm Front case the isentropic trough configuration does not exist (see Warm Front Band , Warm Front Shield and Detached Warm Front ).

According to the sub-types Warm Occlusion Type, Cold Occlusion Type and Neutral Occlusion Type (see Occlusion: Warm Conveyor Belt Type - Key Parameters ) the following three vertical distributions of frontal zones can be expected. In the investigation carried out by ZAMG two main different configurations could be observed:

• A Warm Front type: in this case the isentropic trough is forward inclined on top of the Warm Front zone.
• A Warm Front inclined crowding zone in front of and a Cold Front inclined crowding zone behind, the isentropic trough feature. In this case the forward inclination of the isentropic trough is not as strongly pronounced as in the other case. Sometimes also a straight vertical trough axis can be observed.

The field of the relative humidity is characterized by high values, of about 80% and even more, within the area of the isentropic trough. In the case of a forward inclined trough the maximum values of the humidity have forward inclination, two low values of relative humidity can be observed within and below the lower isentropes of the Warm Front - like crowding zone. This minimum typically is situated between approximately 800 and 700 hPa. A second minimum of the relative humidity can be found on the rear side of the isentropic trough within the upper levels of the troposphere at approximately 300 hPa. This corresponds to the following dry intrusion.

The whole area of the Warm Front inclined crowding zone and the leading part of the isentropic trough feature is under the influence of pronounced WA. The maximum of WA mostly can be found within the lower levels of the troposphere very close to the area where the Warm Front inclined crowding zone reaches the surface. A secondary pronounced area of WA can be found within the upper levels of the troposphere on the rear side of the isentropic trough. This area is typically situated at approximately 300 hPa and indicates the tropopause. The lower and mid-levels of the troposphere are characterized by pronounced CA. The zero line of temperature advection is close to the minimum of the isentropic trough in the lower and mid-levels of the troposphere. Very often the zero line in these levels is characterized by a forward inclination which leads to the development of a potentially unstable stratification of the troposphere (see Meteorological physical background and Key parameters).

The field of vorticity advection is characterized by PVA within the whole area of the Occlusion. Typically two PVA maxima can be found in the cross section. The main maximum exists in the upper levels of the troposphere on the rear side of the isentropic trough and is connected with the left exit region of a jet streak; a weaker PVA maximum exists within the Warm Front inclined crowding zone in the lower levels of the troposphere at approximately 800 hPa. This maximum is connected with the already pronounced cyclonic circulation in these levels and indicates the propagation of the low area (see Meteorological physical background and Key parameters).

The field of divergence shows pronounced convergence within the area of the Warm Front inclined crowding zone and within the lower part of the leading area of the isentropic trough configuration. In the upper part divergence prevails. The zero line of divergence can be found very close to the trough axis.

According to the distribution of convergence, temperature advection and vorticity advection, the field of vertical motion (omega) shows a wide area of strong upward motion within the area of the occlusion. The strongest upward motion typically can be found within the mid-levels of the troposphere.

In the VIS image the whole frontal cloud band is characterized by high pixel values. In contrast to this the pixel values in the IR and WV images depend on the location of the cross section as well as on the stage of development. During the initial stages the pixel values of the IR and WV images within the area of the dry intrusion, close to the point of the Occlusion, are characterized by lower values typical for low and mid-level cloudiness. Downstream of the cloud spiral the pixel values are increasing continuously. During the maturing stages, when the cloud spiral is also accompanied by high cloudiness within the whole cloud spiral, the pixel values are as high as in case of an Occlusion of the Warm Conveyor Belt type (see Occlusion: Warm Conveyor Belt Type ).

The isentropes show an inclined crowding zone similar to a Warm Front with unstable behaviour within the lower levels of the troposphere and an isentropic trough configuration which is forward inclined. High values of humidity can be found forward inclined within the leading part of the trough, humidity minima within the Warm Front inclined crowding zone at approximately 500 hPa and at the rear side of the Occlusion cloud band at approximately 300 hPa. The latter represents the dry intrusion. The field of temperature advection shows strong WA within the leading part of the Occlusion and strong CA within the rear part of the Occlusion. The zero line within the lower and mid-levels of the troposphere has a forward inclination which leads to the development of a potentially unstable stratification of the troposphere. The field of vorticity advection contains only the high level PVA maximum mentioned above: a PVA maximum at approximately 400 hPa at the rearward edge of the cloud band (around 34W48N). However within the lower levels, between approximately 600 and 800 hPa, there is some PVA, but a typical PVA maximum is not seen. The main feature in the field of divergence is a pronounced convergence zone within the lower layers of the Occlusion trough extending upward in the Warm Front - like crowding zone. Pronounced divergence can be found above this zone. The field of omega shows strong upward motion within the whole area of the Occlusion.