Have you ever wondered why temperatures vary around the Earth? This lesson will examine some factors, including latitude, elevation, atmospheric circulation, different heating between land and water and ocean currents that affect temperature variance.
Marlie the Meteorologist is back to teach you everything you want to know about temperature! Now, if you don’t remember, Marlie studies the weather and is going to take us around the world in order to investigate factors that influence the temperature, or how much heat energy is present on the Earth. So, pack your bags because we’re about to head out!
Let’s start at the equator. Wow, it’s nice and warm! The first thing that influences the temperature on Earth is the latitude, or how far north or south a place is from the equator. The equator is at a latitude of 0 degrees.
Let’s zoom in and check out a city that’s pretty near the 0 degree latitude mark. Quito, Ecuador falls at 0.2333 degrees south latitude. The average monthly temperature only varies by about 1.8 degrees Fahrenheit throughout the year and high temperatures hover around 70 degrees Fahrenheit. I don’t know about you, but Marlie seems to be enjoying herself in Quito!Why is it so warm at Quito? Because the Earth is round, the equator receives a lot of heat energy from the sun. The further north or south you go from the equator, the less heat energy the Earth receives.
So, because of its location near the equator, Quito’s temperature doesn’t vary much and remains relatively warm.Now let’s head north to a latitude of 90 degrees! Brrr; there is less heat energy up here so the temperature is lower. The same holds true at 90 degrees south of the equator! Let’s zoom in on a city that’s near the North Pole, specifically 82 degrees north. Welcome to Alert, Nunavut in Canada.
Unlike Quito at the equator, the average monthly temperatures vary by 66.6 degrees here in Alert. The average winter highs are in the -30s and summer highs are in the 40s. So, due to its location near the North Pole, Alert experiences huge variations in temperature as well as frigid temperatures. By comparing Quito to Alert, you can see what a big deal latitude plays in temperature! I can tell Marlie is ready to get out of here!
Altitude ; Elevation
Next, let’s look at altitude and elevation and how they influence the Earth’s temperature. Now, before we climb any mountains, let’s get our vocabulary straight because altitude and elevation are often interchanged.
Altitude is the distance above a given point, whereas elevation is the distance above sea level. You often hear elevation used for geographical features, like a mountain, and altitude used while traveling in a plane.So, why does the temperature change as you gain elevation? Grab your climbing gear, let’s ascend a mountain and find out! As you climb, you may start to notice it’s getting colder. Why? Well, as you ascend, the molecules in the air get further and further apart and are less likely to collide with one another. When molecules collide, heat is exchanged, so, with no collisions, there is less heat energy and the air cools.As we increase elevation, it gets colder. The same would hold true for altitude.
As you gain altitude (say, in a plane), the temperature decreases. If you check out mountain communities, you’ll notice their average temperatures are quite a bit lower than areas at sea level. Let’s get off this mountain and check out our next factor that influences the Earth’s temperature!
Atmospheric Circulation Patterns
Atmospheric circulation patterns are due to uneven heating of the Earth as well as the Earth’s rotation and cause cells of winds throughout the Earth. These winds redistribute heat. For example, warm air from the equator heads north where it cools, sinks, and heads back to the poles. Of course, it’s a little more complicated and there are different cells, but you get the general idea.
These cells cause wind, like the Polar Easterlies, which can be found near the poles. The Polar Easterlies bring cold, frigid air into that region.Or, closer to the equator, you can find trade winds that blow warm, steady wind. Without these circulation patterns, heat would not be distributed and the temperature ranges on Earth would vary even more dramatically than they already do! Okay, okay, Marlie can’t wait to get to the next factor that influences the Earth’s temperature.
Let’s head to the California coast to check out the difference in heating between land and water.
Land ; Water
It’s a gorgeous day in San Francisco, and Marlie is taking in the sights! But, how will San Francisco teach us about the different heating and cooling of land and water? Excellent question! You might notice that during a hot, sunny day, a body of water feels chilly. But, at night, the same body of water feels warm.
This is because, compared to land, water takes a really long time to warm up. That’s why the water feels cold compared to the sand when it’s a hot, sunny day. But, on the flip side, the water takes a long time to cool down. So, at night, when the sand is cold, the water feels warm.In many coastal regions, like San Francisco, the ocean regulates the temperature on land.
Remember, it takes water a long time to warm up! In the summer, when San Francisco gets warm, the ocean is a little cooler. This cold ocean water, prevents the temperature from getting too high during those hot, summer days.Now, fast forward to the winter: San Francisco gets colder but the ocean takes a long time to cool down so it still has some of the heat it obtained during the summer. As a result, the ocean keeps San Francisco relatively warm.
If you were to compare the temperatures in San Francisco to a city a little further inland, like Bakersfield, you’d see the ocean prevents San Francisco’s temperature from fluctuating too much. San Francisco’s high temperatures range from about 57 degrees in January to the mid-60s in the summer. Compare that to Bakersfield, which has a January high of 56 degrees Fahrenheit and highs in the 90s throughout the summer months.
Warm ; Cold Ocean Currents
Finally, let’s check out how ocean currents impact the Earth’s temperature. Like wind in the atmosphere, ocean currents move heat energy throughout the Earth. Also like the atmospheric circulation, the ocean has patterns of circulation. Specifically, ocean currents are movement of water that redistributes heat energy and are made up of surface and deep ocean currents.
Wind primarily influences surface currents, whereas differences in density results in deep ocean currents. Both of these types of currents are involved in a 1,000 year cycle that brings cold, dense, deep water from the poles to the equator and warm, less dense water from the equator to the poles.Let’s check out a few examples. For the first example, we can stay on the west coast where the California Current brings cold water from the poles to the west coast, thus cooling the west coast water.
Now, let’s travel to the east coast of the United States where the Gulf Stream brings warm, equatorial water to the North Atlantic Ocean, thus keeping the southeastern coast of the United States fairly warm. I don’t know about you, but Marlie’s getting pretty tired! All of this travel sure takes a lot out of a person!
Before we go, let’s review the factors that influence the Earth’s temperature, starting with latitude. The further north or south you get from the equator, the colder the average temperature. Remember Quito versus Alert? Next, we climbed a mountain and looked at altitude and elevation, and learned that the higher you get from sea level, the colder the average temperature.Then, we looked at atmospheric circulation and saw how wind redistributes heat throughout the Earth from the trade winds to the Polar Easterlies. From there, we traveled to California where we saw how the different heating of water and land results in mild climates along the California coast, like San Francisco. Finally, we examined ocean currents, where we saw cold ocean currents along the west coast and warm ocean currents along the east coast.
Wow, I can see why Marlie is tired! Not only was that a lot of traveling, that was a lot of info!