Computer-Controlled Automated Rain Sampler (CCARS) for Rainfall Measurement and Sequential Sampling

Abstract

The Computer-Controlled Automated Rain Sampler (CCARS) is a combination rain gage and sequential sampler for precipitation chemistry measurements. The primary objectives of the design are low cost, versatility of operational mode, and remote siting using battery power. The three major components of the device are the measuring valve (rain gage), sequential distribution valve, and onboard computer that also serves as a controller and data recorder. The measuring valve uses an electromagnetically operated plunger and optical sensors to divide rain events into adjustable rainfall increments (nominally 0.01 in.). The distribution valve, using a stepping motor and a rotating channeled gear, delivers programmed volumes to nine sequential stages. The computer records rain and stage increment timing and can be programmed to sample on a time or volume basis.