Author Question: What features in Earth's general circulation help determine where the driest and wettest places on ... (Read 55 times)

leo leo · **on:** Jul 13, 2018

What features in Earth's general circulation help determine where the driest and wettest places on Earth are found?

What will be the ideal response?

Question 2

Does the position of the polar jet stream change during the year? If so, how and why?

What will be the ideal response?

quynhmickitran · **Reply #1 on:** Jul 13, 2018

Answer to Question 1

ANSWER: The position of the major features of the general circulation and their latitudinal displacement (which annually averages about 10 degrees to 15 degrees) strongly influence the precipitation of many areas. On the global scale, abundant rainfall occurs where the air rises and very little where the air sinks. Consequently, areas of high rainfall exist in the tropics, where humid air rises in conjunction with the ITCZ, and between about 40 degrees and 55 degrees latitude, where middle-latitude cyclonic storms and the polar front force air upward. Areas of low precipitation are found near 30 degree latitude in the vicinity of the subtropical highs and in polar regions where the air is cold and dry.

Answer to Question 2

ANSWER: On average, jet streams flow from east to west. However, their pattern is commonly a wavy west-to-east pattern. When the polar jet stream flows in broad loops that sweep north and south, it may merge with the subtropical jet. Occasionally, the polar jet splits into two jet streams. The jet stream to the north is often called the northern branch of the polar jet, whereas the one to the south is called the southern branch. Also, the north south temperature contrast along the polar front is strongest in winter and weakest in summer. This situation explains why the polar-front jet shows seasonal variations. In winter, the winds are stronger and the jet moves farther south as the leading edge of the cold air can extend into subtropical regions, as far south as Florida and Mexico. In summer, the jet is weaker and is usually found over more northerly latitudes.