A high-resolution electronic rainfall intensity recorder and totaliser

Abstract

An electronic distant-reading rainfall intensity recorder capable of measuring minute-to-minute values of the intensity of rain and recording them of a strip-chart recorder was designed and constructed at the Instruments Division of the Meteorological Office, Poona. The system measures the intensity of rainfall by converting rainwater into drops of equal size and counts the number of drops by an optical-cum-electronic device. The number of counts during every minute interval which constitutes a measure of the intensity of rainfall are recorded on a conventional strip-chart recorder. To measure the total rainfall during any given interval of time, an additional mark is printed on the chart for every 1 mm of rainfall. The system, which has a resolution of ½ mm of rain/hour, was tested during several spells of rainfall at Poona and was found to record quite accurately.