A good definition for geography in general is the study of the earth and the movements upon it. Obviously, this creates a great deal of overlap into other sciences as it entails the sociological elements of how people move and interact with each other, how space is defined both in a real sense as well as in a virtual or metaphysical sense and thus tying in the processes of physics and metaphysics. Physical science is, of course, necessary to understand the processes of the earth itself and the physical places in which they occur. Geography is both strengthened and weakened by this broad application of the term in that it provides numerous areas of research and development and provides a bridge between many concepts yet it is easily complicated and obscured.
Weather refers to the activities that are taking place within the atmosphere at any given time such as rain, hurricane, calm, cloudy or windy. Climate refers to the average weather experienced in a given area during a given season of the year as it has been recorded in books or in memory for an unspecified span of time.
A concept that relates to both weather and climate is temperature. The temperature outside on a given day will begin to give an impression of what the weather might be like – 92 may mean a good day at the beach while 24 indicates heavy coats and gloves are needed. This is related to climate in that the average yearly temperatures in Texas are not likely to reach 24 very often while the average yearly temperatures in Alaska are not likely to see 92 on a regular basis.
The greenhouse effect is the process that causes the Earth to become warmer than other planets as a result of having an atmosphere. Global warming refers to the increases in the natural greenhouse effect of the planet as a result of human pollution. They are different in that one is a natural process and the other is caused by human activities. Global warming can have the effect of artificially heating up the earth to abnormally high levels, causing the ice caps to melt, increasing ocean levels and reducing their salinity, and causing plant functions to change, perhaps making them less resistant to invading bugs and illnesses. This would have a profound impact upon all life depending on the regulating forces of the ocean, the water cycle or the plants and animals.
The pressure gradient force is the power that causes air to move from one area of high pressure to an area of lower pressure, dictating the wind speed based upon the grade of difference between the high pressure and low-pressure areas like the grade of a skiing hill dictates the speed of the skis. The Coriolis Effect is the effect of the Earth’s rotation on anything moving in its atmosphere. In the Northern Hemisphere, this means that anything becoming wind-born, including the wind itself, is deflected to the right of its original path as it is affected by the movement of the earth, which is more pronounced at the poles and less evident at the equator.
Frictional force is the natural drag on wind speed, forcing the air at the bottom of the column to slow down as it drags across other objects. As air heats up in the tropical zones, it rises aloft and is carried toward the poles. By the time it reaches the subtropical zones, it has condensed with other columns of air on the way to the pole and begins to subside while the heated air prevents condensation and rainfall creating deserts.
At the same time, these winds are deflected to the right by the Coriolis Effect and become the Trade Winds. The Westerlies are the continuation of air columns toward the poles out of the subtropical zone which lose much of their pressure by the time they reach the subpolar lows, caused by the meeting of these winds and the polar highs which tend to move in an easterly, opposite direction. In areas such as the subtropics, high-pressure systems meeting high-pressure systems reduce rainfall by preventing water condensation while areas such as the subpolar regions are low-pressure areas where condensation is encouraged and large storms can occur. Mountains and other high landforms can also cause pockets of high and low-pressure areas where rainfall becomes more prevalent.
The climate found along the coast of southern California is generally mild, without much fluctuation in temperature year-round and mild winds coming off the ocean while the climate in South Carolina is more volatile and unpredictable. The reason for this is the difference in wind patterns in the two places. On the west coast, ocean currents are cold and don’t produce the same sort of high-pressure systems seen on the east coast where water temperatures coming up from the equator are much warmer and give rise to high-pressure systems.
El Nino refers to an anomalous change in water temperatures in which warmer water is brought to the east Pacific disrupting the normal wind patterns. This creates drought conditions in the western Pacific where pressure zones typically provide a large amount of rain and creates flood conditions in the normally dry eastern Pacific. This can disrupt fishing patterns as food fish follow different currents of nutrient-rich cooler waters and disrupts plant growth cycles on the land as the plants get either too much or not enough rain.