Compare an injected water volume with the ideal rainfall depth over a known collector opening.
Preparing interactive controls…
1 mL = 1 cm³, so expected depth(mm)=10×volume(mL)/opening area(cm²). Relative reading error=100(reading−expected)/expected. Area must be the collector opening, not a narrow measuring tube. This is a geometric check, not a complete dynamic calibration.
10 mL through a 100 cm² opening equals 1 mm. A gauge reading 1.1 mm is high by 0.1 mm, or 10%.
Use the effective collector opening area, not the inner measuring cylinder. Confirm volume and manufacturer procedures; a pouring check does not characterize wind or intense-rain errors.
Method reviewed November 4, 2026. These tools support learning and recording, not safety-critical decisions.
