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Calvin Weather Station: Instruments
Calvin College maintains a weather station under the supervision of Dr. Deanna van Dijk for the purpose of measuring and recording local weather conditions. The weather station is located in the southwest corner of the Calvin College Ecosystem Preserve. Instruments on the tower record barometric pressure, temperature, relative humidity, wind speed and direction, and incoming solar radiation. A rain gauge is located near the tower.

The weather tower.

A Barometric Pressure Sensor measures atmospheric pressure. (The sensor is mounted inside the white enclosure on the tower.)

Temperature and humidity are measured with a Vaisala HMP45C probe mounted inside a radiation shield at a height of 1.5m.

An R.M.Young Wind Monitor measures wind speed and direction at a height of 3m.

A pyranometer measures incoming solar radiation. The pyranometer is mounted on a cross-arm which extends south from the tower to avoid shadows cast by the tower.

A Campbell Tipping Bucket Rain Gage measures precipitation. The rain gauge is mounted on a steel pipe (at a height of 1 meter) approximately 3 meters southwest of the instrument tower.

The instruments are connected to a Campbell Scientific CR10X datalogger housed in the white enclosure on the north side of the tower. The datalogger is linked to the Calvin College communications network by underground cable. Data can be retrieved from the weather station manually by means of a removable storage module which is connected to the datalogger. The tower is topped with a lightning rod which gives the tower a total height of 3.5m above the ground.
Notes about Calvin College weather data collection:

  • All measurements are recorded in metric units and English units.
  • 30-minute averages and totals are for the 30 minutes preceding the time given.
  • Temperature, relative humidity, wind speed, wind direction, and solar radiation are measured every 15 seconds; the measurements are averaged or totaled to produce the 30-minute values.
  • Daily values for temperature, relative humidity, wind speed, wind direction and solar radiation are the 24-hour (midnight to midnight) averages or totals of measurements made every 15 seconds.
  • Barometric pressure is measured every 30 minutes and recorded as measured.
  • Rainfall values are the total precipitation recorded in the preceding 30-minute time period or the preceding 24-hour time period.
  • The rain gauge measures only liquid precipitation, not snowfall. During winter months, recorded precipitation may result when accumulated snow melts in the rain gauge. These values DO NOT represent the water equivalence of the snowfall and are time-lagged after the snow event.