WMO CONCLUDES THE INTERCOMARISON TEST: 5 STARS FOR CAE RAIN GAUGE
The World Meteorological Organization - WMO published in these days the final results of the intercomparison test on rain gauges, carried over during 4 years over instruments produced by the most famous manufacturers all over the world. The CAE tip-and-bucket rain gauge is on the top platform with the highest ranking of five stars, gained both in laboratory and field tests. Out of the 25 instruments tested, only 2 share with CAE this outstanding result.
WMO final report on intercomparison is available at site (http://www.wmo.int/pages/prog/www/IMOP/publications/IOM-99_FI-RI.pdf). Results were achieved after a series of laboratory test, followed by 2 years of field tests conducted at Vigna di Valle (Italy) and concluded in April 2009. 25 rain gauges, selected among the best at international level, were tested and compared.
The preliminary testing was worked out in three major laboratories of France, Italy and Holland from 2004 to 2006. Out of it, only four rain gauges were selected, that exposed to reduced precipitation patterns of different intensity and duration, gave the best results in terms of accuracy and reliability. These instruments were subsequently employed as reference instruments for the field intercomparison. Between them, CAE manufactured rain gauge PMB2 was present.
The tester-rain gauges were later on installed in four specially conceived grit-tras, dug in field testing selected site. Measurement obtained, protected from atmospheric instabilities, were used as reference values to be compared with measurements obtained from installed rain gauges, operating in regular conditions.
This methodology allowed the correct testing in open field of reliability and accuracy of all instruments submitted to the intercomparison, as a function of their sensitivity against variable atmospheric conditions.
In open field intercomparison, the second CAE rain gauge, installed and operating under regular environmental conditions, obtained excellent results, giving back data of highest accuracy, reliability and precision, thus obtaining the highest marking.