Although we generally do not recognize it, we live at the bottom of a vast sea. Unlike the liquid water that makes oceans we are familiar with, but the Earth’s atmosphere is composed of numerous onion-like layers of air. This air, even if it is a gas rather than a liquid, still behaves in much the same way as any other liquid. This invisible ocean of nitrogen, oxygen, argon and other trace gases fluxes, compresses, swimming pools and deforms as it moves around the Earth, and the science of Meteorology is an attempt to understand and predict these movements and their results.
As with any fluid, seeking the atmosphere constant stability. In an ideal world, it would be the same air temperature and humidity throughout the entire atmosphere. Of course, we do not live in an ideal world. Solar radiation, rotation and tilt of the Earth and other factors ensures that stagnation is never reached. The weather can be thought of as a big engine that has to try to rid the atmosphere of this imbalance and to return to a State of balance, and throughout this series, we will look at different ways, it does this. But first, let’s examine how this imbalance originates.
Although the atmosphere is a continuous body of air, it is composed of many smaller air masses. An air mass is a quantity of air, which has roughly the same temperature and moisture content throughout. There are four primary types of air masses, named by where they originate. “Continental” air masses are so-named because the strains over large landmasses, and they tend to be drier. “The sea” air masses originated over large bodies of water and tends to hold more moisture. These air masses are further defined by their temperature, with “tropical” air masses that have a higher temperature than “polar” air masses. Taken together, the four types of continental tropical air mass (cT), continental polar (cP), maritime tropical (mT) and maritime polar (mP). A fifth air mass, continental Arctic (cA) contains dry, bitterly cold air and is seen much less frequently in the middle latitudes.
These air masses move as large tectonic plates all over the globe, and as the earthquake caused by the collision between the two plates, most big weather occurs when two air masses collide. The meeting between the two air masses is known as a front, and type of front depends on how air masses interact. Because the majority of widespread weather occurs in the vicinity of the fronts, they are an important factor in understanding and predicting storms. Below are the types of fronts and weather that normally expected along them. Is the symbol used for each front on the surface analysis view card under each heading.