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Blowin' in the Wind, Issue #069 How do Air Masses Affect Climate - Aug 1, 2009
August 04, 2009
How do Air Masses Affect Climate?
Curious people ask How do Air Masses Affect Climate? If you are interested in meteorology, it is natural that you are going to wonder about something like how come "Red in the morning sailors warning, Red in the night, sailors delight," was known to all our seafaring ancestors; itís even given in the Bible in Matthew 16. They knew everything about the weather, and they knew that it could change suddenly from stormy to calm in a jiffy.
Just imagine you having to be living in a high-pressure subtropical belt. Suddenly, tropical winds as well as polar winds from the Arctic decide to have a high-powered meeting. Result -- storm, and definitely not one in a teacup.
Apart from this, you are also going to find high temperature fluctuations, especially in winter. That means there is either a polar mass of cold air moving over your area or possibly some hot air decided to make its presence felt in your vicinity.
Really, How do Air Masses Affect Climate?You must understand that any air mass is defined as a large quantity of air, which is going to have some water vapor and is either going to be cold or hot. These masses are not restricted to a narrow column, extending a couple of miles above your head. They are going to cover hundreds of miles horizontally. And if the surface of the earth underneath them is hot or cold, wet or dry, they take their temperature and moisture characteristics from the earth accordingly.
Any sort of air Mass is classified and named according to its latitude and the place of origin. A weather front is going to separate an air mass with different moisture, density and temperature characteristics.
The different types of air masses that you can find on the earth are equatorial, tropical, Arctic and polar. You can label an air mass a continental air mass or a maritime air mass. As can be seen by the name, maritime air masses grow and gather over the oceans and seas. These are extremely humid. Continental air masses are formed over land masses and continents, and remain quite dry.
Now, just imagine that you happen to be living in England. Suddenly you find yourself subjected to want to make your friendly neighborhood meteorologist says is a cP air mass. It means it is a continental and polar air mass and colder than the land over which it looms. In Alaska, you might be treated to cA-mP (or mPk) air masses, occasionally. This is a clash between continental, blowing up from the Arctic and monsoon related air masses, which are polar in origin and of course colder (kolder!) than the Bonnie Land of Alaska underneath them. By the way, warm air masses are denoted with the letter w, go figure.
Example: How Do Air Masses Affect The Climate?Every single air mass begins to acquire the characteristics of the region which it occupies for a period of time. A polar air mass is made when the lack of daylight chills the atmosphere so that the air immediately above the land grows cold. On the other hand, sunlight falling directly on the surface of the sea causes so much evaporation that you end up with a maritime air mass bubbling up right in front of your eyes. The moment two air masses confront each other, -- just like upon any battlefront, - that area can be considered to be a front. The weather changes quickly so from tropical warm weather you can suddenly find the air, turning cold, and vice versa. One of these severe weather changes occurs when a polar air mass (continental in origin, and cold) clashes with the tropical air mass, which is maritime in origin and humid and warm. This is how air masses can affect weather in an inclement manner.
Here is another example of air mass interactions. See how they create chinooks and affect places like Alberta. You can even comment on this one if you like.
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