Maintenance system and technology used in FMI´s observation network Jani Gustafsson Introduction FMI´s observation network consists of different type of stations and technology. Technical maintenance and development of observation system networks plays a very big role. Because the technology is developing constantly the methods and techniques of the observations have also been developed. This means that the meteorological parameters have been increased significantly. Evaluating the new technology and selecting the most suitable one is very challenging. It´s also very important to remember to train the technicians to understand and meet the requirements of how to maintain the new instruments. Observation technology group The observation technology group is responsible for the technical management and maintenance of the FMI's instruments and observation stations.The measuring instruments must meet the accuracy requirements. This means that instruments require periodic maintenance. Maintenance of the stations is performed regularly as well as calibrated according to accepted calibration procedures. The observation technology group is divided into two teams: field and central maintenance. The duties of field maintenance teams are technical maintenance and development of observation system networks The central maintenance team takes care of our electronic, calibration and electrical laboratory systems. They do instrument maintenance and calibration services. This includes for example temperature sensors annual calibrations to ensure traceability. Groups common duties are: FMIs Development and Research Support Help Desk Services Technical Quality assurance Technical maintenance The measuring instruments must meet the accuracy requirements. This means that sensors require periodic maintenance. Stations are visited according to a yearly maintenance plan. Report of all maintenance visits is drawn up by the station technician. Each weather station is visited at least once in a year. Maintenance work on site: Replacement of the sensors before their calibration lifetime expires At the fault events the sensor is changed. Replacement, calibration or repair of sensors Temperature every year Wind sensors every year at marine stations, every second year for majority of the stations Humidity every year Pressure every three years Precipitation every year Visibility every year testing Checking the sensor leads and cables Positioning of the wind vane will be checked each year This check will be performed by using a compass The declination is also taken into account Mowing the grass, weeding Cleaning of the instruments Keeping an eye out for any changes in the surroundings Error reporting system Error reporting system is a centralised tool for managing error reports of the automatic weather station network. It is a web based software where all users can make a report of suspected problems with a station. The status of errors and their resolution can be followed. The system allows effective maintenance coordination. When an error in data is noticed and the fault is reported to the system the report is forwarded to the responsible technician. The technician fixes the error and documents all phases of the process. The process can be followed on the webpage. All participants are notified by of every change in the process. Technology used Temperature: Pentronic Pt-100 Humidity: Vaisala HMP35/45 humidity probes Pressure: Vaisala PTB220 barometers Wind: Vaisala WAA/WAV 151, 251, and 252, Thies Ultrasonic 2D wind sensors Global radiation: Kipp&Zonen CM11 pyranometers UV-radiation: Solar Light SL501 Visibility / present weather: Vaisala FD12P Cloud height: Vaisala CT25K, CL31 ceilometers Snow height: Campbell SR50A(H) snow height sensors Data loggers: Vaisala QML201, Milos 500