Wendy has taught high school Biology and has a master's degree in education.
How's the Weather?
Do you ever wonder why certain regions of the world tend to have the same types of weather patterns? Take the United States, for example. The closer you are to the equator, the warmer the temperature.
The southwest is typically very warm and dry. Places on the Pacific coast tend to have mild temperatures, and the Pacific Northwest is rainy. Areas in the Midwest see more extreme temperatures and humidity.
Why the consistent patterns? The truth is, even though weather can change on a daily basis, the general climate of an area is usually predictable. This consistency is due in large part to atmospheric climate phenomena that dictate our weather patterns.
Although climate and weather are not exactly the same, there is a very direct relationship. Join us as we take a look at types of climate phenomena that affect our weather.
Climate and Weather
Before we get started, it is important to define both climate and weather.
- Climate is the average weather that occurs in a particular area over a period of time such as a year.
- Weather, by contrast, describes the conditions outside on a day-to-day basis. Basically, weather is the result of how the local atmosphere is acting on a given day.
For example, the general climate of a place such as Phoenix, AZ is dry and warm, with lots of sunshine. However, the weather on a given day in Phoenix could include rain, wind and even snow.
Climate of a particular area is affected by physical factors such as elevation, latitude, proximity to the ocean and nearby mountains. However, phenomena occurring in the atmosphere on a global level play a very large part in determining the climate and weather of an area. One such phenomenon is the jet stream.
The Jet Stream
If you have ever watched a weather forecast, you have most likely seen a map showing a curvy line stretching from west to east. This is known as the jet stream. The jet stream is not actually air produced by a jet; it refers to bands of very strong winds high up in the atmosphere.
These winds form as air is heated unevenly and temperature differences develop. The earth's rotation helps create these currents, and the jet stream carries the air masses across the globe. The line of the jet stream marks the boundary of these cold and warm air masses.
The jet stream usually moves west to east, but not always. When its path changes, this can drastically affect weather conditions.
For example, sometimes the path of the jet stream alters its course and dips from north to south. When this happens, it means that icy polar air from the north can drop farther south than usual. This change can certainly make for interesting and possibly extreme weather!
There is one part of the earth that consistently changes and affects weather patterns: the ocean. Ocean currents are a driving force behind the weather we experience. And when ocean water temperatures fluctuate, we see changes in weather as well. This is the case with El Niño.
El Niño occurs when water temperatures in the equatorial Pacific Ocean become warmer due to a phenomenon called southern oscillation. When the atmospheric pressure in the tropics oscillate (fluctuate), wind patterns change. This allows warm surface water to flow east, causing general changes in ocean temperatures.
These warmer ocean temperatures directly affect weather patterns in various locations, creating an El Niño effect. An example of this is during El Niño winters, the southern U.S. tends to receive more precipitation than usual, sometimes even causing flooding.
North Atlantic Oscillation
Oscillations in the Atlantic region occur as well. When atmospheric pressure changes in the northern Atlantic area, variations in wind occurs. This can cause climate changes, affecting temperatures and precipitation in North America, Europe and Asia.
In certain areas of the U.S. and the world, there is a distinct rainy season during which every day can bring heavy rains and storms. These are known as monsoons. Monsoons usually occur because of changing wind direction due to seasonal temperature differences between water and land.
Monsoons are unique because they aren't just storms that last for a day; they last for months! Your area may not experience monsoons, but they do cause general changes in overall climate.
Climate refers to the general weather over long periods of time in an area, and weather refers to changing temperatures and precipitation on a daily basis. Climate phenomena affect weather patterns in particular regions. Phenomena includes:
- jet stream - bands of very strong winds that form as air is heated unevenly and temperature differences develop. The line of the jet stream marks the boundary of cold and warm air masses, and carries these across the globe.
- oscillations - water temperatures in oceans fluctuate, changing wind patterns and weather patterns in many areas. El Niño effects are caused by southern oscillation.
- monsoons - long periods of storms due to changing wind direction from seasonal temperature differences between water and land.
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