Unattended long‐period evaporation recorder

Abstract

An evaporimeter installation is described consisting of a battery‐operated long‐period recorder coupled to a supply water tank and raingauge. The supply tank is connected to a standard evaporimeter through an automatic control valve, which regulates the supply of water to replace that lost by evaporation, and disposes of excess water due to precipitation, so that evaporation in all weather conditions can be recorded. The equipment is capable of operating for periods up to 6 months unattended, the recorder having an accuracy within ± 0·01 in. water level.