A Robust Microwave Rain Gauge

Abstract

In this paper, we present an all-electronic rain gauge that uses microwave sensors operating at either 10 or 24 GHz and measures the Doppler shift caused by falling raindrops. It is straightforward to interface the microwave rain gauge with conventional data loggers. A disadvantage of the microwave rain gauge is that it consumes significant power when operating. However, this may be partially negated by using the data loggers' sleep-wake-sleep mechanism. Advantages of the microwave rain gauge are that it is robust, does not clog, and does not have mechanical parts that wear out. Prototype microwave rain gauges were collocated with tipping-bucket rain gauges, and data were collected for several seasons. At higher rain rates, microwave rain gauge measurements compare well with tipping bucket measurements. At lower rain rates, the microwave rain gauge provides more detailed information than widely used tipping buckets, which inherently quantize measurements.