Air mass

Air Mass in Meteorology and All of the Air Mass Types

Air masses have many effects on several regions of the planet, but not everyone understands how important they are. Once you learn about them, you often feel fascinated by their movement and how they impact the weather. For example, they can originate hail, thunderstorms, or dust showers.

By reading the guide, you can learn valuable information about air masses such as their definition, types, classification, where they originate, and more. Don’t forget: you can share it with your family and friends so they also understand the importance of that meteorological phenomenon and feel amazed by it!

Air Mass Definition

An air mass is an air volume in the atmosphere, and it’s usually very large. Additionally, it’s often uniform in terms of moisture and temperature

Although you might not be able to imagine it, air masses can extend thousands of kilometers over the Earth’s surface. They can also go from the ground level to the stratosphere

Air masses typically form over surfaces with uniform temperatures, and those areas are called source regions. When the wind carries the masses, they move specific weather types from one source region to another one.

For an air mass to occur, the source region must have specific characteristics, such as the temperature and humidity remaining stable during a time long enough for the occurrence to happen.

Air Mass Types

There are different types of air masses, and knowing them is important to understand where you can find them and how they affect their surroundings.

Meteorologists often study air masses and they divide them into different types depending on where they’re located. For example, artic ones are located in that region, and it happens the same way with the rest of the kinds.

Tropical Continental

The Tropical Continental air mass has its origins in the north of Africa and the Sahara Desert. The source region is very warm, and it usually originates the mass in June, July, and August, which are summer months. However, it can also occur at other times of the year.

Even though it’s one of the most important air mass types, it’s very hard to visualize it. Its air often picks pollutants when it passes through Europe, and many Saharan dust storms throw dust particles that hinder visualization.

Sometimes, when the air mass occurs, dust particles from the Sahara Desert shower cars, houses, and everything on their path. That often looks as if it was an orange rain.

Tropical Maritime

The waters of the Atlantic Ocean also host an air mass, which occurs between Bermuda and the Azores. Across the British Isles, the common direction for the air is to move from south to west.

Unlike Tropical Continental, Tropical Maritime is moist and warm on its lower layers but stable and saturated when it passes over cool waters. Therefore, when it locates in the British Isles, it can even create fog.

The Tropical Maritime air mass can produce a rising in temperature, and it occurs during the winter month.

Polar Continental

Originating in Eastern Europe and Russia, the Polar Continental air mass is considered an exclusive phenomenon of the winter since it occurs between December and April.

The Polar Continental air mass is unique because its weather depends on how long its sea track is when it passes from Europe to the British Isles. If it moves over the English Channel with a short sea track, it brings severe frosts and clear skies, although it’s still very cold.

Across the British Isles, the lowest temperatures happen in the air mass, and they can reach freezing temperatures during the whole day.

Polar Maritime

Northern Canada and Greenland originate the Polar Maritime air mass, which moves towards the British Isles from north to west.

Although several air masses reach the British Isles, the Polar Maritime is the one that frequently affects them. The temperatures usually start being very cold, but eventually, they warm up and end being completely unstable.

Additionally, the air mass often brings showers, especially when its unstable temperature is at its peak. For example, it often creates thunders and hail storms on the west and north areas of the British Isles.

Arctic Maritime

The characteristics of the Arctic Maritime air mass are similar to the ones that the Polar Maritime has. However, since the sea track is shorter, the air is less moist and colder.

It’s a very rare occurrence during the summer, but it can still happen. When it does, it often provokes unseasonably cold weather and storms.

The Arctic Maritime originates in the Arctic Ocean and the North Pole, and it often reaches its peak between October and May. That frequently ends in strong hails and storms, particularly in Scotland.

In the north of Scotland, the effects of the Arctic Maritime can provoke immensely cold weather. However, in other parts of Britain, the coldest air comes from the Polar Continental.

Returning Polar Maritime

The Polar Maritime has an alternative version that is called the Returning Polar Maritime. In that case, the air mass has a long sea track.

Additionally, the length of the sea track results in immensely unstable air. Nonetheless, when the air moves from north to east over the waters, it stabilizes on its lowest layers.

When the Returning Polar Maritime is formed, the first air moves to the south over the north part of the Atlantic and then north-east, arriving at the British Isles.

Classification of Air Masses

Meteorologists classify the air masses according to two factors: the temperature and moisture of their source regions. The criteria are the following:

  • Moisture Content: Continental air masses are dry, whereas maritime air masses are moist.
  • Temperature: Tropical air masses are warm, polar ones are cold, and arctic are extremely cold.

Furthermore, meteorologists often use specific name conventions to classify air masses. The first letter is small, and it is a c or an m, which indicates moisture. Then comes a capital letter, which is a T, a P, or an A, identifying the temperature.


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