35 Rainfall Measurement: Gauges
Part 4. Hydrometeorology
Published Online: 15 APR 2006
Copyright © 2005 John Wiley & Sons, Ltd
Encyclopedia of Hydrological Sciences
How to Cite
Sevruk, B. 2006. Rainfall Measurement: Gauges. Encyclopedia of Hydrological Sciences. 4:35.
- Published Online: 15 APR 2006
It is difficult to measure precipitation without introducing systematic errors or biases. The quality of any measurement will depend on the type of gauge used and the details of the installation, as well as the characteristics of the gauge site including exposure and the prevailing weather. All precipitation measurements using can-type gauges are subject to systematic errors, mostly due to deformation of the wind field above the precipitation gauge orifice, wetting and evaporation losses, splash-out and splash-in, blowing snow, and so on. Because these measurement errors are systematic, precipitation gauges frequently show different precipitation figures. This is the case when the gauges are of different construction, or the same construction, but from different manufacturers, or are installed at different heights at the same site near each other, or under different gauge site exposure. With the exception of measurements of blowing and drifting snow, they show less precipitation than the “true” precipitation falling on the ground. Correction procedures are different for rain and snow. They were developed for different types of precipitation gauges and various time intervals according to the availability of necessary input data. Corrections are based either on empirical field methods using the World Meteorological Organization reference standard, laboratory experiments, or numerical simulation.
- precipitation measurement;
- systematic error;
- wind-induced error;
- exposure of gauges;
- wetting loss;
- evaporation loss;