The letters following each Review Question refer to the corresponding Learning Objective from the Chapter Opener. Explain the nature of cyclones and anticyclones and note their relationship to high-pressure and low-pressure systems. What is a mid-latitude cyclone? (D)

Cyclones are large scale air masses that rotate around a strong center of low atmospheric pressure. This system is characterized by inward spiraling winds that rotate counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. On the contrary, an anticyclone is a weather phenomenon defined by a large-scale circulation of winds surrounding a central region of high atmospheric pressure. They just whirl clockwise in the Northern Hemisphere and counter-clockwise in the Southern Hemisphere.

Cyclones are directly related to low-pressure systems, as they form around areas of low pressure. The low pressure at the center allows the surrounding air to rush in, leading to the spiraling motion of the cyclone. Anticyclones, on the other hand, are associated with high-pressure systems. These high-pressure regions push air outwards, leading to a whirl in a direction opposite to that of the cyclone. The outflow of air results in calm and clear weather conditions.

A mid-latitude cyclone, also known as an extratropical cyclone, involves a weather system occurring in the middle latitudes of the Earth (between 30° and 60° latitude from the equator), having cyclonic (counter-clockwise) flow in the Northern Hemisphere and anti-cyclonic (clockwise) flow in the Southern Hemisphere. It is associated with fronts, i.e., the boundary between two different air masses. These cyclones play a significant role in driving the Earth's general circulation and bringing most of the precipitation received in the mid-latitudes. They are larger and longer-lasting than tropical cyclones. By understanding and comparing these systems, it's clear that cyclones, anticyclones, and mid-latitude cyclones serve as crucial components in the Earth's climatic patterns.