What is albedo and how does it affect the weather?

Snow has a much higher albedo than grass or asphalt, which can explain a number of factors affecting the weather in winter and spring.

Transcript

00:00On those blue sky days when the sun is out and working its magic on the snowpack, you

00:04can actually feel it.

00:06Just walk around and you'll likely find warm and cool spots.

00:09From the cool snow to the warm grass and pavement, the temperature differences are great enough

00:13to feel without a thermometer.

00:15But why is that?

00:17You might be thinking that snow is ice, so of course it's going to be cooler.

00:20That's only part of the story.

00:22One of the reasons it doesn't melt as quickly as you might think comes down to albedo.

00:26Albedo is a measurement of how much radiation is reflected.

00:29The measurement is on a scale of 0 to 1, so 0 would be something that absorbs all radiation

00:36called a black body, and perhaps the closest thing to this would be a black hole.

00:41However, you can see here some common albedo surfaces, including black asphalt, which of

00:46course has a very low albedo.

00:49As you work your way to green grass, a little bit higher.

00:51Desert sand would come in lower than snow, that fresh snow reflecting a lot of it.

00:56When viewing Earth from space, open oceans also have a lower albedo than those of glaciers,

01:04and of course clouds have a higher albedo.

01:07Clouds send a lot of radiation back to the sun, therefore on cloudy days it will always

01:12be a little bit cooler than if you had the same weather and brilliant sunshine streaming

01:16down.

01:17But of course, if you can't get above the clouds, then perhaps you can feel the difference

01:21the albedo makes as winter turns to spring.

01:24On a spring day, especially when there's grass out, that sun's radiation comes down

01:28and most of it is going to be absorbed.

01:31Some of it still goes back up into the sky, but it's a lot different when you have that

01:36snow cover all around.

01:38A lot of the sun's radiation will be reflected back up into the sky and back up into space,

01:43which helps to keep the air a little bit cooler, especially just above that snowpack.