Jet Stream, Integrated Writing, Test 4, Barron

In the passage, the author mainly talks about the definition and classifications of jet stream. In the lecture, the speaker primarily says the effects that jet stream could have on air travel by providing an example.

In the first place, according to what is stated in the article, the jet stream could be described as an irregular band of wind that takes place high above the ground of Earth, about 20,000 feet. Generally speaking, the jet stream always blows from west to east over middle latitudes. Moreover, the speed of jet stream is over 57 miles per hour. The core speeds of jet stream may be as high as 190 miles an hour. Furthermore, the jet stream between the equator and the North Pole can be separated into two categories: subtropical jet stream and polar jet stream. The main distinction between them is that temperatures between the tropic and the arctic regions of the Earth are different.

In the second place, the speaker of the lecture affirms the definition of jet stream at first. Then the speaker says that jet stream in North America is polar jet stream. In the following part of the lecture, the speaker cites an example that airlines travel between Los Angles and New York. When planes are going to New York from Los Angles, they are just in the same direction of jet stream which provides more buoyant force to tail wing. As a result, people spend less time in travelling to New York. However, according to the speaker, when planes go back to Los Angles, the situation becomes tough. Because the planes are flying against jet stream which is strong and fast, planes will use more fuel and fly longer. Passengers in planes will also feel relatively serious turbulence.