Rain gauge calibration

In this section we are going to explain how the Davis rain gauge can be calibrated.

The next pictures shown the tools needed to perform the calibration:

  1. a bottle with a spoun to maintain constant and regular the flux of water;
  2. a structure to vertically keep the bottle over the rain gauge funnel;
  3. a precision balance to fill the bottle with the right quantity of rain.
calibration_tools calibration_tool_1 calibration_tool_2 calibration_tool_3

Hereinafter the steps to follow:

  1. Check that the rain gauge is in level and that the funnel is clean without leaves

  2. Fill the bottle with 53.5 cl of water (535 g).

    calibration_1

  3. Mount the sustain on the rain gauge and put on the bottle.

    calibration_2

  4. Wait until the bottle is empty: be sure that the bottle is completely empty!

  5. Sum the millimiters of water recorded and divide them by 0.2.

  6. The tipping bucket is considered calibrated when for two times consecutively the measured tips are between 118.75 and 131.25 (5% error) or the equivalent measured water quantity is between 23.75 and 26.25 mm.