For a clear understanding of the various types of atmospheric disturbances, the study of air masses provides an essential background. Air masses that move along as part of the large scale motion systems of the general circulation are largely responsible for bringing about changes in the day-to-day weather, particularly so in the middle latitudes.
Therefore air masses also play a dominant role in producing different types of climates. Virtually all the major changes occurring in the day-to-day weather are the result of the advances and interaction of the air masses and of processes within the air masses themselves.
The temperate regions in the northern as well as southern hemispheres may be considered to be the battlegrounds where air masses with contrasting physical properties very often meet.
As we are aware, it is in the middle latitudes where the warm tropical and the cold polar air masses are brought together along the ever fluctuating polar fronts.
That is why the weather of the temperate regions is characterized by extra-tropical cyclones, anticyclones and many other daily weather changes.
Besides, travelling air masses transport latent heat as well as other temperature characteristics from one region to another. Air masses also carry large quantity of atmospheric moisture from over the oceans to the continents to yield precipitation over there.
Most of the migratory atmospheric disturbances or storms which generate a larger part of precipitation all over the world originate at the fronts or the zones of contact between air masses having different physical properties. Weather conditions associated with these storms are largely governed by the characteristics of air masses associated with them.
Remember that the air mass concept was developed during World War I by two eminent Norwegian meteorologists, Vilhelm Bjerknes and Jacob Bjerknes (father and son). This concept is now known as air mass analysis.
Credit goes to Tor Bergeron, J. Bjerknes and Solberg for introducing the air mass concept to the field of meteorology and for forecasting the weather on the basis of air masses. The third decade of the twentieth century (1920-30) witnessed the development of this concept.
In the next two decades the air mass analysis proved of immense help in short range forecasting covering a period of 24 to 36 hours. Air mass analysis technique enabled meteorologists to understand various weather phenomena more clearly.