Apparatus for Measurements of the Electrical Conductivity of Rainwater with High Resolution in Space and Time

Abstract

Apparatus has been designed and constructed for real-time measurements of the electrical conductivity of rainwater. It utilizes a spinning disk that centrifuges and collects the rainwater failing on it A micro conductivity cell is employed, which consists only of electrodes, and needs no embodiment to sustain the rain sample during measurement. Instead the liquid is retained between the electrodes by its own surface tension. Only the order of a microliter of rain water is needed to obtain a inclement. The system's response time is about a second. Test runs during thunderstorms and frontal rains reveal that variations in conductivity by up to a factor of 5 occur during a storm event. Maximum conductivities of up to 160 ?S cm?1 usually occurred at the beginning of the storms. In one thunderstorm rainwater conductivity as low as 5 ?S cm?1 was measured for a duration of a few minutes.