Factors That Influence Rainfall in the United States
Factors that Influence Rainfall in the United States
A type of precipitation is rainfall and it develops when water vapor condenses into droplets in the atmosphere thus becoming too heavy to stay suspended in the air so gravity causes them to fall. The pattern or occurrence of rainfall in the United States or basically anywhere in the world depends on several factors such as ground elevation, wind directions, location within a continental mass, areas of low pressure, cool fronts, jet streams and even mountain ranges. For instance mountains have an influence on wind and wind is an important feature in rainfall, “The windward sides of mountainous islands in the trade wind regime are among the rainiest places on earth, where rains exceed the regional oceanic precipitation by several fold. Over Hawaii, where nearby oceanic rains are of order 50 cm per annum, favored island locations receive rainfall in excess 500 cm yr-1”(Carbone 2847). This means that a part of Hawaii gets significantly more rainfall than the other part and it is because of geographical factors; its mountains push the air mass upward, condensing water vapor into droplets thus creating rainfall. The distribution of rainfall in the United States is somewhat like the distribution of rainfall in Hawaii, there exist dry and wet sides but it all depends on the factors that interfere with the precipitation development of rainfall.
As mentioned before, mountains are one of the factors that cause rain. This is so because in order for the air to pass over mountains it has to rise. So, in mountains such as the Washington Cascades the air is forced to rise to pass over them. This rise causes the air to cool, condensing and creating rainfall on one side, like Seattle, and leaving the other side with the dry air receiving very little or no rainfall. This sinking, dry air is the result of what is called the rain shadow effect, an area in the lee of a mountain with less rain and cloud cover (Brinch 1).
A type of precipitation is rainfall and it develops when water vapor condenses into droplets in the atmosphere thus becoming too heavy to stay suspended in the air so gravity causes them to fall. The pattern or occurrence of rainfall in the United States or basically anywhere in the world depends on several factors such as ground elevation, wind directions, location within a continental mass, areas of low pressure, cool fronts, jet streams and even mountain ranges. For instance mountains have an influence on wind and wind is an important feature in rainfall, “The windward sides of mountainous islands in the trade wind regime are among the rainiest places on earth, where rains exceed the regional oceanic precipitation by several fold. Over Hawaii, where nearby oceanic rains are of order 50 cm per annum, favored island locations receive rainfall in excess 500 cm yr-1”(Carbone 2847). This means that a part of Hawaii gets significantly more rainfall than the other part and it is because of geographical factors; its mountains push the air mass upward, condensing water vapor into droplets thus creating rainfall. The distribution of rainfall in the United States is somewhat like the distribution of rainfall in Hawaii, there exist dry and wet sides but it all depends on the factors that interfere with the precipitation development of rainfall.
As mentioned before, mountains are one of the factors that cause rain. This is so because in order for the air to pass over mountains it has to rise. So, in mountains such as the Washington Cascades the air is forced to rise to pass over them. This rise causes the air to cool, condensing and creating rainfall on one side, like Seattle, and leaving the other side with the dry air receiving very little or no rainfall. This sinking, dry air is the result of what is called the rain shadow effect, an area in the lee of a mountain with less rain and cloud cover (Brinch 1).
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