The study attempts to carry out field testing of the weighing raingauge for measurement of rainfall, which is at the core of all hydrological measurements. The tipping bucket rain gauges are generally used for automated recording of rainfall data. It has been reported that the tipping bucket mechanism of such raingauges frequently malfunctions and gives erroneous data, especially during high intensity rainstorms.
Accurate measurement of rainfall is an essential requirement in hydrological studies and weighing type raingauges are considered to be reliable.
The study describes the development and testing of a weighing rain gauge, using components and systems available indigenously. The weighing type rain gauge with electronic data logging circuitry was developed and tested at NIH campus in Roorkee. The rain gauge has a capacity of up to 130 mm rainfall following which the gauge has to be emptied through a draining mechanism.
With the reported rain gauge, the total amount of rainfall can be measured continuously, and the rainfall intensity can be derived. The rainfall observations from the Weighing Rain Gauge (WRG) were compared with that of the other standard rain gauges – SRRG and ORG, at a site in Roorkee. The results of the field testing during 1996-97 are presented in the report.
The field testing confirmed a resolution of 0.2 mm of rainfall when compared with the standard SRRG type raingauges used in the country. The complete unit is battery operated and is suitable for extended field operations.
With the reported rain gauge, the total amount of rainfall can be measured continuously, and the rainfall intensity derived. In view of the shortcomings discussed above, further field testing is necessary to establish the efficacy of WRG over the conventional raingauges.
Download the report here:
/articles/field-testing-weighing-raingauge-research-report-national-institute-hydrology