Appearance in Satellite Data

Arctic Fronts form in the Arctic region, and move southwards in southerly flows. When they reach Northern Europe, they have usually travelled over an open sea, and convective cloudiness has developed. The appearance of an Arctic Cold Fronts is then, essentially, that of a shallow Cold Front.

Arctic Cold Fronts are usually so far north that Meteosat images alone are inadequate to recognize them. Also, the following conceptual models may look like Arctic Cold Fronts: polar Cold Front, Polar Low and Comma. The final check is best made using a loop of AVHRR images with the help of numerical model parameter fields.


As stated in the Common Remarks, Arctic Cold Fronts can be classified into two types:

  1. Baroclinic fronts
    These fronts resemble polar cold fronts, but are usually not so extensive. The frontal cloudiness becomes more convective with time.
  2. Ice/sea boundary fronts
    These fronts form over the ice/sea boundary and move southwards with the basic flow. There is only an isolated Cold Front. Often this type is so shallow and weak that it can not be detected in Meteosat water vapour images.

Examples of both types are given below.

 

Appearance in Meteosat images

  • light grey to white band in IR and VIS images
  • light grey to grey band in WV images
23 March 2009/12.00 UTC - Meteosat 9 IR10.8 image. The location of the Arctic Front is shown in the images with a frontal line.
23 March 2009/12.00 UTC - Meteosat 9 WV6.2 image
23 March 2009/12.00 UTC - Meteosat 9 VIS0.6 image
23 March 2009/11.29 UTC - NOAA 18 VIS0.6; VIS0.9; IR10.9 RGB image

Another example of an Arctic front over land is show below. The Arctic air mass over the north-western part of Russia can be seen in extremely cold surface temperatures over land , but - unlike for sea cases - the convective cells are absent. Most of the cloudiness associated with the Arctic front is upper level thin Cirrus clouds denoting the place of the baroclinic zone.

05 February 2009/09.00 UTC - Meteosat 9 IR10.8 image. The location of the Arctic Front is shown in the images with a frontal line.
05 February 2009/09.00 UTC - Meteosat 9 WV6.2 image
05 February 2009/09.00 UTC - Meteosat 9 VIS 0.6 image
05 February 2009/09.00 UTC - Meteosat 9 HRV + HRV + IR 10.9 RGB image