| An Essential, Basic And Fundamental Description Of Meteorology |
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 Pablo Edronkin
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People often complain about weather forecasts because they are not totally accurate; but what most people ignore is that meteorology is an exceedingly complex science, and forecasts are made only on a statistical basis. Yet, the principles of meteorology and climatology are very simple in deed. Climate can be defined succinctly as the average weather over a very long period of time, and weather as the short term variations of the phenomena that occur in a planetary atmosphere. Whenever a planet receives energy – normally from a sun or star, but something big an noxious like an A-bomb will also do -, it has an atmosphere and has movement, it will develop weather patters and with them, a climate. 
Our planet moves around the sun following an elliptical orbit; it also rotates around a tilted axis of vertical symmetry. It is not a sphere but a flattened body due to centrifugal forces and thus, it has become a rather big hyperboloid (meaning a 3D body which, if sliced like an onion vertically, would produce elliptical sections). There are gases in our atmosphere, and the planet receives energy from the sun. The gaseous mix that remains around the surface due mainly to gravitational forces and we know as atmosphere, is greatly influenced by all these forces, and our weather and climate are a result of that. If we alter this process, then we can change the weather and ultimately, our climate. There are two important kinds of movement affecting the atmosphere: first of all, since along the equator the energy that reaches the surface is a little bit more than in polar regions due to the fact that the diameter of the planet is slightly longer horizontally than vertically, air is warmed up and tends to ascend. As it does and that generates big areas of low pressure, air coming from elsewhere tend to fill the void; this air is cooler and comes from areas nearer the pole: in the northern hemisphere, thus you have cool air moving southwards until it reaches the equator, and in the southern hemisphere, winds move from Antarctica and up north. This is very general, of course, as there are local variables and exceptions, but we can say that there is a convective movement of air that climbs at the equator, then moves north, gets cooler in polar regions, descends and then return to the equator filling the void left by yet more air. To this, we must add that as Earth rotates eastwardly, air masses are also affected by inertia. So, winds also tend to rotate to the east, and this produces the famous Trade Winds near the equator. 
But the fact that cold and warm air have different densities, and that they meet together not only around the equator but below and above the tropics, produces more or less violent clashes, the storms. As a general rule, the bigger the difference in temperature, speed and density of two air masses, the more serious will be the resulting storm. There is yet another factor that influences the violence of a storm, and that is how warm air goes up: if it does all over a mass of air in – so to speak – a tranquil fashion, then no air turbulence will develop and you will witness the formation of stratus-type clouds. These can produce rain and snow, but never produce storms with lightning, hail and all that stuff. But if the air boils and bubbles up, it forms cumulus-type clouds, and if these grow sufficiently, they become self-sustaining convective systems that can be several thousand meters high, like furnaces. Inside these cumulonimbus clouds, particles suffer friction and generate static energy as a result; then, sparks begin to appear, and that is the beginning of a storm. In some cases, the energy of the cloud is used-up quite rapidly; however, if a storm cell joins another or acquires a perfectly vertical shape that turns it into a fairly closed energy convective system, then it may last longer and even grow. If a cumulonimbus acquires an anvil shape in which the top – usually touching the stratosphere – begins to split from its vertical position and becomes really marked, then the cloud is beginning to die because the precipitation that it produces doesn’t return in full to the virtual chimney that the cloud has become. That’s an energy loss which in time will become faster than what convection produces, and so the storm ends. These are the most fundamental principles of meteorology; they will allow you as an outdoor enthusiast to understand what is going on around you without the need to rely completely on weather forecasts produced by someone else. However, the story gets far more complicated from this point and it is the reason why forecasting is so complex and difficult. 
If you are interested in learning more about this topic, we recommend you to look for yet more posts on meteorology and weather forecasting at our forum; you can also read our reviews and articles plus, a quite a few books and learning products on the issue. |
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