The letters following each Review Question refer to the corresponding Learning Objective from the Chapter Opener. Why do prevailing winds develop at the Earth's surface? Why do the jet streams form? (C)

Prevailing winds are winds that blow predominantly from a single general direction over a particular point on the Earth's surface. They develop as a result of the Earth's rotation, unequal heating of Earth's surface, and the Coriolis Effect. To understand their development, we need to look into these factors and how they influence the wind patterns on Earth.

The Earth's rotation and its uneven heating create convection currents in the atmosphere. The equatorial region gets more direct sunlight, which causes the air to heat up, expand and rise. At higher altitudes, the air moves towards the poles. In contrast, the polar regions receive indirect sunlight, making them cooler. The cold air contracts and descends towards the Earth's surface, where it moves towards the equator. This movement of air creates a circulation system that forms the basis of prevailing winds.

The Coriolis Effect is a consequence of the Earth's rotation, which causes the moving air to be deflected relative to the Earth's surface. In the Northern Hemisphere, this deflection causes winds to turn right, while in the Southern Hemisphere, it causes winds to turn left. This effect results in the formation of large-scale wind patterns, such as the trade winds, westerlies, and polar easterlies. These wind patterns constitute the prevailing winds at the Earth's surface.

Jet streams are high-altitude, fast-moving air currents that circle the Earth in a west to east direction. They form at the boundaries between warm tropical air masses and cold polar air masses.

The formation of jet streams can be attributed to several factors. Firstly, the temperature difference between the warm tropical air and the cold polar air generates a pressure gradient, which drives the wind. Secondly, the Earth's rotation and the Coriolis Effect cause these winds to move in a west-to-east direction. Lastly, the conservation of angular momentum causes these winds to be concentrated in narrow bands, resulting in fast-moving air currents at high altitudes. These factors together give rise to jet streams in the atmosphere. To summarize, prevailing winds develop at the Earth's surface due to the Earth's rotation, unequal heating, and the Coriolis Effect. Jet streams form as a result of the temperature difference between warm tropical air and cold polar air, the Earth's rotation, and the conservation of angular momentum.