Rainwater sampler & analyzer (UNS 130/E)
This device has a rain sensor which controls its opening. The container therefore only opens when it rains and allows to only take rainwater and its dissolved minerals (which are then analyzed). This avoids accounting for any dry deposits (aerosols, fog...), which we can sometimes have with conventional rain gauges.
Rainwater sampler & analyzer (UNS 130/E) ;
Diagram based on manufacturer guide