Rain gauge acc. to Diem

The amount of precipitation falling on an area is characterized by the height - measured in mm - at which this precipitation would cover the ground in liquid form if it had not infiltrated, run off or evaporated.

To determine the precipitation amount, the precipitation falling on a small section of the affected area is collected and measured at specific observation dates. The measurement result is interpreted as the average value for the entire observation area.

Since precipitation amounts can vary considerably from location to location, measurement accuracy depends on the ratio of the measuring area to the total observation area, as well as on the appropriate choice of measuring site. Since the ratio of the measuring area to the observation area can only ever be extremely small for economic reasons, particular attention must be paid to the selection of the measuring site for rain gauges.