What is the primary purpose of a Campbell Stokes recorder?

What is the primary purpose of a Campbell Stokes recorder?

• A. Measure rainfall
• B. Record sunshine duration
• C. Record wind speed
• D. Measure humidity

Answer: (B)

Sunshine duration is what this instrument is built to track. A Campbell Stokes recorder uses a clear glass sphere to concentrate sunlight onto a recording card. When the sun shines, the focused heat burns a trace into the card. The length of that burned trace corresponds to the number of hours of bright sunshine during the day, so meteorologists can determine daily sunshine duration. It does not measure rainfall, wind speed, or humidity; those require a rain gauge, an anemometer, and a hygrometer, respectively. Modern practice often uses electronic sensors, but the Campbell Stokes recorder is a classic tool specifically for tracking how long the sun shines.

Sunshine duration is what this instrument is built to track. A Campbell Stokes recorder uses a clear glass sphere to concentrate sunlight onto a recording card. When the sun shines, the focused heat burns a trace into the card. The length of that burned trace corresponds to the number of hours of bright sunshine during the day, so meteorologists can determine daily sunshine duration. It does not measure rainfall, wind speed, or humidity; those require a rain gauge, an anemometer, and a hygrometer, respectively. Modern practice often uses electronic sensors, but the Campbell Stokes recorder is a classic tool specifically for tracking how long the sun shines.