All measuring results contain errors. When using high accurate instruments, the measuring error is small; otherwise, the measuring error is big. If any measuring instrument doesn't pass the calibration or verification, its measuring value doesn't have a relation to trace the origins, so the measuring value is not trustworthy.AWS is composed of various meteorological sensors (air pressure, air temperature, ground temperature, air humidity, wind direction, wind speed, precipitation and so on), data-collecting, data-processing, data-storage and data-display, etc. It is the same as other ordinary meteorological instruments that as time goes on the measuring errors of various meteorological sensors and data-loggers will drift. In order to guarantee the accuracy, the reliability, the comparability on the measuring value, using the same standard meteorological instruments and relative calibration equipment in accordance with verification regulation or calibration specification and to carry out the periodical verification and calibration of various meteorological sensors and the data-collecting of AWS are very important. By means of the analysis on the calibration results' uncertainty, it is an importance stage to examine the reliability of the calibration or verification results.How to carry out the evaluation of the uncertainties of the verification results is the technique problem which usually occurs when setting up a standard and replying to the check. Because the instrument structure principle and the using environment conditions are different, the quantity of type B standard uncertainty is different. According to JJF1059-1999 "evaluation and expression of uncertainty in measurement", the method of the evaluation for type A standard uncertainty, the evaluation of synthesize standard uncertainty and the evaluation of expand uncertainty are the same. The evaluation of type B standard uncertainty is different. It must be noticed that, when carrying out the evaluation of the uncertainties in the measurement, it is not repeated and not left out. Otherwise, it will bring nonscientific or unjust judgment for the evaluation and expression of the uncertainties of the verification or calibration results.According to verification regulation of AWS, evaluation and expression of uncertainty in measurement (JJF1059-1999), the simplification evaluation of uncertainty in measurement and the verification or calibration data, the uncertainty of measuring results of different meteorological sensors will be analyzed in details, it has important instructional significance to the evaluation of the credibility of other type AWS and normal meteorological instruments verification result.
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