Air mass (meteorology)

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Air masses tend to be separated by fronts.

The term air mass is used in meteorology and climatology when describing relatively uniform parts of the troposphere .

In weather forecasting , the modeling of air masses with a uniform temperature or humidity is an important method to predict the course and temporal development of fronts .

In particular, the sliding of warm air masses over relatively colder air masses is a physically easy to model process, by means of which the increase in relative humidity and the formation of clouds or precipitation can be predicted with great accuracy.

For some phenomena, much larger-scale calculations of the movement of air masses are possible - for example in the case of the global, very stable system of trade winds or jet streams .

Air mass classification

The air masses are classified on the basis of studies at the University of Bergen from 1918 to 1923 under the direction of Vilhelm Bjerknes , his son Jacob , Halvor Solberg and Tor Bergeron . In his dissertation (1928) Bergeron demonstrated that the temperature and humidity characteristics of air masses do not change over a longer period of time while they flow over the earth's surface. The boundary between two air masses is referred to as the front and is therefore essential information for weather forecasts, because the weather can also change with the front . The difference in these air masses was attributed to two main factors. The latitude of education according to four regions:

Regions of origin of air masses
Arctic or Antarctic (A / AA)
Polar (P)
Tropical (T)
Equatorial (E)

and the surface conditions in these regions:

continental (c) masses over the mainland that are relatively dry and
maritime masses over the seas that are relatively humid.

Eight basic air masses can be calculated from this. However, since arctic or Antarctic air masses are always dry and equatorial air masses are always very humid, six basic classes remain:

Abbr. Designation designation Temperature characteristics Humidity characteristics
A or AA Arctic / Antarctic arctic air masses extremely cold, is formed over the poles very dry from the cold; continental is not differentiated from maritime
cP Continental Polar continental subpolar air very cold, formed over the subpolar zones very dry due to the cold and the formation over a land mass
mP Polar Maritime polar sea air Very cool, due to the high latitude, not too cold due to the moderate influence of the ocean moderately humid due to low temperatures, but not as dry as the continental air masses due to evaporation on the sea surface
cT Tropical Continental Continental tropical air very warm, because of the formation over the subtropical lower latitudes dry, as formed over land.
mT Tropical Maritime tropical maritime air very warm, because of the formation over the subtropical lower latitudes very humid because of the warm water of the seas
E. Equatorial Equatorial Hot Extremely moist; Continental is not differentiated from maritime, since large areas of land are covered by tropical rainforests.

Air masses of Europe

The weather in Europe is mainly influenced by the following air masses.

abbreviation designation geographical origin
cA continental arctic air North Siberian arctic air
xA Arctic air Northern European arctic air
mA maritime arctic air North Sea -Arktikluft
cP continental subpolar air Russian subpolar air
xP Subpolar air Northern European sub-polar air
mP maritime subpolar air North Atlantic subpolar air
cPs warmed continental subpolar air warmed subpolar air
xPs warmed subpolar air Aging across Europe
mPs sub-polar air heated by the sea Way over subtropical seas
cSp continental air of the middle Widths (Eastern) European continental air
xsp Mid-latitude air (Western) European air
mSp maritime air of the middle Widths North Atlantic sea air
cS continental subtropical air Southeast Europe. Subtropical air
xS Subtropical air Southern European subtropical air
mS maritime subtropical air Atlantic subtropical air
cT continental tropical air African tropical air
xT Tropical air Mediterranean tropical air
mT maritime tropical air Atlantic tropical air

See also

Web links

Commons : Air masses  - collection of images, videos and audio files
  • Air Masses And Fronts , Meteorology 101: Understanding weather forcast , Dept. of Meteorology, Pennsylvania Stat University (Eng.)


  1. ^ Brian Taylor (2002) The Air Mass Concept ; Retrieved May 11, 2012
  2. a b c d Keith C. Heidorn (2005) Air Masses: A Base for Weather Analysis ; The Weather Doctor; Retrieved May 9, 2012
  3. Weather lexicon of  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , accessed on May 11, 2012@1@ 2Template: Toter Link /