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Weather Lab 6-8 / Week 11 / Wednesday
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Week 11 · The Climate Record

Wednesday

Station Lab: Anomalies from your log
// How NOAA and NASA measure a warming planet
⏱ about 20 min

Wednesday: Station Lab: Anomalies from Your Log

Raven spreads the Station Rooftop log across the table. Ten weeks of temperatures run down the page in pencil.

"Today we do what NOAA does," she says. "Turn readings into anomalies."

Rocket adds up the column and divides. "Our average so far is 58," he says. "So every day is either above it or below it."

"What do you notice if you color the above days red and the below days blue?" Raven asks.

Nova hovers over the page and traces a line straight across at 58. "That line is your baseline," she says. "Everything else is a story."

Rocket colors the first bar. It pokes up above the line like a little red flag.

"Warm day," he says. "Plus four."

Your mission

You will calculate your own baseline from your station log, turn each reading into an anomaly and draw a bar chart.

NOAA converts readings into anomalies because the goal is to track change. You will do exactly that with your own data.

If your log has gaps, use the days you have. Eight or more readings make a good chart.

  • Your station log with temperature readings
  • Graph paper or plain paper and a ruler
  • A red pencil and a blue pencil
  • A calculator, or scrap paper for adding and dividing
Safety first
This lab uses paper and pencils only. No new outdoor readings are needed today.
If you do take a reading, never go outside during a thunderstorm, flood or high wind.
  1. Copy up to ten temperature readings from your log into the table, one per row, with the date.
  2. Add all the readings together. Divide by how many readings you have. Round to one decimal. This is your baseline.
  3. Predict: how many of your days will be above the baseline? Write your prediction in your journal.
  4. For each day, subtract the baseline from the reading. That number is the anomaly. Write it in the table.
  5. Draw a horizontal line across the middle of your paper and label it with your baseline.
  6. For each day, draw a bar. Above the line in red for a positive anomaly, below in blue for a negative one.
  7. Count the red bars and the blue bars. Compare with your prediction.
  8. Look for a pattern. Do the red bars cluster in one part of the chart?
DateReading (F)Baseline (F)Anomaly (reading minus baseline)
PREDICT BEFORE YOU COLOR
  • Read the question.
  • Tap your answer.
Your warmest reading is 9 degrees above your baseline. What sign will its anomaly have?
A reading exactly equal to the baseline has an anomaly of what?

What your chart shows, and what it cannot

Your chart is a real anomaly chart, built the same way NOAA and NASA build theirs.

But your baseline is a few weeks long. A climate normal is 30 years long.

Your red and blue bars show weather: warm spells and cool spells in your area.

NOAA's chart of yearly anomalies since 1880 shows climate. It has been 48 years since Earth had a cooler-than-average year.

The difference is time. Weather is a few bars. Climate is the whole chart over many decades.

What the lab showsTrue or false?
An anomaly is the reading minus the baseline.?
A positive anomaly means a day warmer than the baseline.?
Your ten-week baseline is a climate normal.?
NOAA has recorded a cooler-than-average year within the last 48 years.?
WHY THIS EXERCISEBuilding an anomaly chart yourself is the best way to read NOAA's.
NOAA's chart of yearly anomalies shows ____ years since the last cooler-than-average year. Type a number.
A reading below the baseline makes an anomaly that is ____. (positive or negative)
FROM READINGS TO ANOMALY CHART
  • Tap a card.
  • Then tap its spot.
1First
2Second
3Third
4Last
Try it
Ask a family member to guess, without looking, how many of your days were above the baseline. Then show the chart.
Were they surprised? A chart often shows a pattern that a list of numbers hides.
On paper, draw your finished anomaly chart neatly: the baseline, red bars above and blue bars below, each labelled with its date.

Excellent data work. Tomorrow you read the real NOAA and NASA numbers.

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