Med-Hycos - les Données
Base de connaissance
WEIGHTING RAINFALL RECORDER
In these instruments, the weight of a receiving can plus the precipitation accumulating in it is recorded continuously, either by means of a spring mechanism or with a system of balance weights. Thus all precipitation is recorded as it falls
This type of gauge normally has no provision for emptying itself, but by a system of levers, it is possible to make the pen traverse the chart any number of times. Theses gauges have to be designed to prevent excessive evaporation losses.
The main utility of this type of
instrument is in recording snow, hail, and mixtures of snow and rain. It
does require that the solid precipitation be melted before it can be recorded.
CONDITIONS OF USE
All gauges in any area or country should have comparable exposures, and the same siting criteria should be applied to all. The gauge should be exposed with its orifice being horizontal over ground level. The height of the gauge orifice above the ground should be as low as possible because the wind velocity increases with height, but it should be high enough to prevent splash from the ground. A standard height of one metre is recommended.
When adequate conditions from the
wind is not possible, individual objects should not be closer to the gauge
than a distance equal to four times their height.
Ring collector with a sharp edge
linked to a cone-shaped funnel with a sufficient slope to avoid splashing