Traceability and Online Publication of Weather Station Measurements of Temperature, Pressure, and Humidity

A project to enhance the quality of climate data has been running at the Italian Institute of Metrology (INRiM) since 2007. The focus of the project has been the installation and development of a weather station to monitor temperature, air humidity, and pressure; the collection and storage of the measurements; and the provision online to allow open-access. The project aims to improve the traceability of measurement through development of calibration and measurement protocols able to be applied to the wide variety and geographical spread of weather stations. The data collected have a short traceability to the national standards and a well-known uncertainty budget. In this work the project progress in terms of data collection and calibration of the weather station is reported. The instant measured values of the weather parameters have been published online, as is a complete database of the recordings, stored in daily, monthly, and annually collected data archives. This is the first example at the Italian national level of an archive of reliable climate data open to public access. A traceability study was carried out through calibration of the weather station instruments both in situ (over the course of one seven-hour period) and in the laboratory (under the full range of expected temperature, humidity, and pressure conditions). Significant differences in the results of the two calibrations are noted and implications for the provision of traceability discussed.