Abstract
This paper describes four rainfall recorders and gives the results of laboratory and field investigations carried out at the Road Research Laboratory to determine the accuracy of the instruments.
The instruments used were:
Standard Meteorological Office total‐rainfall recorder,
Meteorological Office rate‐of‐rainfall recorder,
Road Research Laboratory combined total‐rainfall and rate‐of‐rainfall recorder (orifice type).
Road Research Laboratory rate‐of‐rainfall recorder (channel type).
A laboratory study of the accuracy of the instruments was followed by examination of the records obtained of 49 storms occurring between the summer of 1951 and the autumn of 1952.
It was found that mean rates of rainfall between given times could be measured within about 5 per cent from the records from all the instruments, but that the chart speed of the Meteorological Office total‐rainfall recorder is too slow for peak periods of short duration to be located accurately. The principal advantage of the Road Research Laboratory combined total‐rainfall and rate‐of‐rainfall recorder is that it provides a clear picture of the shape of the storm curve which is very helpful in the analysis of the records.