Chapter 22, Problem 7A

Why does the direction of coastal winds change from day to night?

To determine

To Explain: The reason behind the change of direction of costal winds from day to night.

Explanation of Solution

Introduction:

The flow of wind takes place from sea to land during the day and land to sea during the night. The temperature difference will drive convection as well as offshore winds.

During daytime, shores gets warm easily in comparison to water. So, the air above the shore will be heated and rises up. Thus, a low pressure area is formed over the land. As air flow from high pressure region to low pressure region , so wind will flow from sea to land. During night, reverse process takes place. Specific heat of land is less than the specific heat of water. So, water cools more slowly at night. The air above the water will be warmer than that of land. Thus, low pressure area will be formed over the sea and wind will flow from land to sea.

Conclusion:

Hence, the direction of wind changes from day to night because of change of heat from day to night.