Weather Whys; The Land Breeze

This is weather-wise. You may have experienced the sea breeze on a summer afternoon at the beach. It's the persistent, cool wind that comes off the ocean. But you may have noticed during a moonlight stroll along the beach that the breeze reverses itself at night. Then, it's called a land breeze because it blows from the land to the ocean. Just like the breeze coming off the sea, the land breeze occurs because of a difference in the way land and water handle heat. The ground doesn't store energy very well, so at night it quickly radiates away the energy received from the sun during the day. But the ocean can store a lot of energy, and its temperature doesn't change much at all. We say the heat capacity of water is much greater than that of the land. But as a result, at night, the air over the land will become cooler than the air over the ocean.

That warmer air tends to rise and create a small area of low pressure over the water. Incidentally, that moist rising air contributes to the development of thick fog banks, which may move on shore in the morning when the sea breeze starts up. The cooler air over the land tends to sink, creating a little area of high pressure. We know air tends to move from areas of high pressure to those of low pressure. So air from the high pressure zone over the land will drift into the low pressure zone over the ocean, and the land breeze is the result of it. Weather-wise is produced with the assistance of the National Weather Service Forecast Office and the National Severe Storms Laboratory, both in Norman, Oklahoma, and the Cooperative Institute for Mesoscale Meteorological Studies, the Oklahoma Climateological Survey, and the School of Meteorology, all at the University of Oklahoma. Weather-wise is made possible by a grant from the National Science Foundation. For Weather-wise, I'm Drew Barlow.