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Weather Lab 6-8 / Week 01 / Thursday
4/6
Week 01 · Weather or Climate?

Thursday

Reading the troposphere
// The state of the air today, and the pattern over many years
⏱ about 20 min

Thursday: Reading the Troposphere

Rocket watches a plane draw a white line high above the roof. "Is there weather up there too?"

Nova dims the lab lights and projects a graph: height on one side, temperature on the other.

"The National Weather Service measured this," she says. "What do you notice as you go up?"

Raven reads the numbers. "It gets colder. A lot colder. And the layer is taller at the equator than at the poles."

"So weather lives in a layer that is thick in the middle and thin at the ends," Rocket says.

"And it is the layer we live in," Raven adds, pulling her jacket tighter.

Nova brightens one line on the graph. "Now read the numbers yourself."

Real data: how tall is the troposphere?

The National Weather Service JetStream school describes the troposphere, the lowest layer of the atmosphere.

Almost all weather occurs in this layer. Its height depends on where you are on Earth.

The table below reproduces the heights the National Weather Service gives.

Place on EarthHeight of the troposphere
At the equator11 to 12 miles (18 to 20 kilometers)
At 50 degrees north or southAbout 5 and a half miles (9 kilometers)
At the polesJust under 4 miles (6 kilometers)

The National Weather Service also reports the temperature change inside the troposphere.

As you climb, the temperature drops from an average of about 62 degrees Fahrenheit (17 degrees Celsius) near the ground.

At the top of the troposphere it reaches about minus 60 degrees Fahrenheit (minus 51 degrees Celsius).

So inside the troposphere, temperature decreases with height.

READ THE TABLE
  • Read the question.
  • Tap your answer.
Where is the troposphere tallest?
About how tall is the troposphere at the poles?
What happens to temperature as you climb through the troposphere?
Average temperature near the ground, in degrees Fahrenheit (type the number).
Height of the troposphere at the equator, in miles: 11 to ____ (type the number).
Height at the poles is just under ____ miles (type the number).

Why this matters for your station

Your station sits at the very bottom of the troposphere. Every reading you take is a sample of this layer.

The National Weather Service processes more than 210 million weather observations each day in the United States.

Your log adds one more set of observations, taken the same careful way.

Scientists who read a table ask three questions. What is being measured? What are the units? Where is the biggest change?

In the table above, the units are miles and kilometers, and the biggest change is between the equator and the poles.

In which unit, besides miles, does the table give the heights? Type one word.
WHY THIS EXERCISEChecking units first keeps you from mixing up two very different numbers.
FROM THE GROUND TO THE TOP OF THE TROPOSPHERE
  • ?Near 12 miles up over the equator: the top of the troposphere.
  • ?Near 4 miles up over the poles: the top of the troposphere.
  • ?Climbing higher: the temperature keeps dropping.
  • ?Near the ground: about 62 degrees Fahrenheit on average.
WHY THIS EXERCISEOrdering the heights shows that the weather layer is thick in the middle and thin at the ends.
On paper, sketch the troposphere as a band around a circle for the Earth: thick at the equator, thin at the poles.
Try it
With a grown-up, look up today's observations for your area from the National Weather Service.
Compare the official temperature with your own log or your own sense of the air. Are they close?

Strong data reading. Tomorrow you connect weather and climate to everyday choices.

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