How Does Ocean Temperature Affect Air Temperature?
The ocean temperature affects the air temperature by producing a moderating effect on the nearby land, and can even affect locations far inland to a certain degree. The ocean is, perhaps, the single most influential force on the planet for influencing temperatures. It can bring cooler weather to locations that would otherwise be very hot, and warmer weather to locations which would otherwise be very cold.
Perhaps the most common example of the effect of the ocean temperature on a land mass is the Gulf Stream, which has an effect on the weather in the British Isles. The Gulf Stream, a warm water ocean current which starts in the Gulf of Mexico and runs around the the Florida Straits up through the Atlantic ending near the British Isles, is one of most famous ocean currents. It not only allows England and Scotland to have much more mild weather than its latitude would suggest, it also is responsible for the area's consistent rain.
While this may be the most commonly-cited example, ocean currents exist all over the world. Some are cold water currents, carrying cooler water from the arctic areas down toward the tropics. Others, such as the Gulf Stream, do the opposite. Some ocean currents, such as those causing El Niño and La Niña, can have an effect on temperatures and weather patterns all over the globe.
The reason why ocean temperature has such an effect on air temperature has to do with the properties of water, and the fact that there is so much of it on the Earth. Changing the ocean temperature is much more difficult than changing the air temperature because water does not heat up, or cool down, as fast as the air. Therefore, the ocean temperature presents a much more moderating force on global temperature.
Rocks and other landforms heat up fairly quickly in the day and cool down quickly at night. That affects air temperature through the radiant heating and radiant cooling process. However, the ocean temperature counteracts these processes by not changing temperatures as quickly. Therefore, it also affects the air around it through the same radiation processes.
On a microscale, the effects of ocean temperature can easily be seen at the beach. Usually, air temperature at the beach is a few degrees cooler than the air temperature over the land just several miles inland during the day. Likewise, during the night, the air temperature at the beach may not cool down quite as much as those inland locations. This is why coastal areas like San Diego have one temperature forecast for the beach, and another for inland areas.
Written by Ken Black
