Classification of Air Mass

An air mass is a huge envelop of air, which has relatively homogenous properties in terms of temperature, humidity, and stability. The length of this air mass sometimes measured even thousands of kilometers and width measured as hundreds of kilometers. Such a huge body of air significantly affect the respective weather system. Interestingly, based on its place of origin and its properties, air mass is classified into various types. In this article, we will discuss the different types of air mass along with their properties.

Classification of Air Mass

Primarily, air mass is classified on the basis of its source of origin and the temperature properties. Source region are the geographic areas where air mass develops over period in time and hence acquires the property of that specific region.

Likewise, to understand the different types of air mass, first we need to understand certain abbreviation that used in air mass classification:

• c – the small ‘c’ defines continental (i.e. land area) and

• m – the small ‘m’ defines maritime (i.e. ocean surface).

Second terminologies are:

• P – the capital “P” defines polar region and

• T – the capital “T” defines tropical region.

Now, based these two types abbreviation, the air mass is classified as:

Air Mass	Source Region	Temperature (oC)	Specific Humidity (g/kg)	Stability
Maritime tropical (mT)	Tropical and subtropical oceans	22 to 30	15 to 20	Conditionally stable
Continental tropical (cT)	Subtropical deserts, especially Sahara and Australia (poorly developed in winter)	30 to 42	5 to 10	Conditionally stable
Maritime polar (mP) Winter		0 to 10	3 to 8	Conditionally stable
Maritime polar (mP) Summer		2 to 14	5 to 10	Conditionally stable
Continental polar (cP) Winter	Usually Between 450 and 600	-30 to -20	0.06-0.2	Stable
Continental polar (cP) Summer	Usually Between 450 and 550	5 to 10	4 to 9	Relatively stable
Continental Arctic (cA) Winter	Antarctica, Arctic Basin, Greenland, interior portions of Eurasia and North America	-55 to -35	0.05 to 0.22	Very stable

Characteristics of Air Masses

Major properties of these different types of air masses are:

• Maritime Tropical (mT) Air Mass: As name mentioned, it is formed over the surface of tropical oceans. Because of its source region, its temperature is warm and humidity is relatively high. But when it moves towards ocean, it causes heavy rainfall along with thunderstorms.

• Continental Tropical (cT) Air Mass: cT originates over the land surface of the tropical region; hence, its properties are hot and dry. And, when such types of air mass moves towards other region, it causes heatwaves and arid conditions.

• Maritime Polar (mP) Air Mass: This type of air mass forms over the water surface of high latitudes. It is cold and humid and when it moves towards land surface, it causes precipitation, usually in the form of snow or rain.

• Continental Polar (cP) Air Mass: This type of air mass forms over the land surface of higher latitudes. Because of its origin place, it is cold and dry. When it moves in the south direction, it downs temperature below the freezing point.

Air Mass Interactions and Weather Patterns

As we discussed above, air mass once formed, it does not stay at one place rather move in defined direction, and when it moves, there is chance to interact with other air mass, which has different properties. Such interaction changes the weather patterns of respective region. Interestingly, when two air masses of different properties interact, they create a boundary between them, known as front.

Conclusion

Moreover, the classification of air mass is a significant aspect to understand the different types of air masses (such as continental or maritime; polar or tropical) and changes in weather patterns that cause of these air masses. Air masses are measure reason of change in weather or sometimes, even sudden change in temperature. It causes high or low temperature, rainfall, snowfall etc.

Frequently Asked Questions

How are air masses classified?

Air masses are classified based on their source region, which is the area where the air mass originates. The main source regions include continental (land) and maritime (ocean) areas, and they are further categorized into Polar (P), Tropical (T), Arctic (A), and Antarctic (AA) regions.

What are the characteristics of Polar (P) air masses?

Polar air masses originate in high-latitude regions and are generally cold and dry. They bring cooler temperatures and are responsible for colder weather conditions in the affected areas.

What is an Arctic (A) air mass, and how does it differ from Polar air masses?

Arctic air masses are extremely cold air masses that originate in the polar regions, usually above the Arctic Circle. They are even colder than typical Polar air masses and can lead to frigid temperatures and harsh winter conditions.

Are there any air masses that form over ice-covered Antarctica?

Yes, the Antarctic (AA) air masses form over the vast ice-covered landmass of Antarctica. These air masses are extremely cold and dry and have similar characteristics to Arctic air masses but are even colder due to the extreme conditions of the southern polar region.

How do air masses influence weather patterns?

When an air mass moves into a new region, it brings its characteristic temperature and humidity properties, which can significantly impact the local weather. For example, a warm and humid Tropical air mass moving into a cooler region can lead to thunderstorms and heavy rainfall, while a cold Polar air mass moving into a warm area can cause a drop in temperature and potentially trigger snowfall.

How are air masses named?

Air masses are typically named based on their source region and their temperature characteristics. For example, a maritime Tropical air mass is abbreviated as mT, where "m" represents maritime, and "T" represents Tropical.

Can air masses change over time, and how do they move?

Air masses can undergo modifications as they travel over different surfaces, such as changing temperature and humidity. They are primarily influenced by prevailing winds and atmospheric circulation patterns, moving from their source regions to new areas, affecting weather conditions along the way.

Why is the classification of air masses important for meteorology?

Understanding the classification of air masses is crucial for meteorologists as it helps them predict and interpret weather patterns and changes. By analyzing the characteristics and movement of air masses, meteorologists can make more accurate forecasts and issue warnings for severe weather events like storms, heatwaves, and cold spells.