DEVELOPMENT OF AWSS NETWORK AT MHS OF CROATIA

Transcription

1 DEVELOPMENT OF AWSS NETWORK AT MHS OF CROATIA Zvonko Zibrat (1), Krunoslav Premec (2), Davor Tomsic (3) Meteorological and Hydrological Service of Croatia HR Zagreb, Gric 3, Croatia (1) (2) (3) Abstract The need for all day data from more locations initiated a development and establishment of automatic weather stations (AWSs) at Meteorological and Hydrological Service (MHS) of Croatia. Since the beginning of 1990ies, number of AWSs in our network has been continuously growing reaching the value of 65 at the beginning of The configuration of AWSs varies from only wind speed and direction measurement to much more sophisticated measurements, additionally including air temperature, relative humidity, air pressure, see temperature, UV-B radiation and precipitation. The philosophy of our AWS is to use central processor unit produced and constantly improved by close cooperation of MHS and our domestic electronic company and different sensors of high quality from worldwide well known companies. Nowadays our main focus is to extend and improve measurements and assure data quality. 1. INTRODUCTION AND HISTORY The need for all day data from more locations initiated a development and establishment of automatic weather stations (AWS) at Meteorological and Hydrological Service (MHS) of Croatia. The pioneering AWS was established in 1979 on the island Vir in central Adriatic see but stronger stress on automated meteorological measurements was put during the war, at the beginning of 1990ies. Department for development, application and performance of special meteorological measurement and Meteorological laboratory have started in 1991 the implementation of telemetric systems (network) for remote transfer of measured data of AWSs which resulted with functioning of the first AWS in Oborovo near Zagreb. Via telemetric system, in this type radio link, data stored in internal memory at the station, were regularly transferred, every hour, in the central computer of MHS, in Zagreb. Due to continuously growing number of AWSs in MHS s network, as well as to harmonized costumer s measurements and needs, MHS issued, in the year 1995, the protocol named Technical requirements and rules for microprocessors, anemographs and AWSs in the MHS s basic network to assure a reliable involvement of different AWSs in the network. 2. PRESENT STATE Number of AWSs in our network has been continuously growing (fig. 1) reaching the value of 65 at the beginning of 2006 (fig. 2). Not all of the stations are owned by MHS. Almost half of them are owned by different costumers like Croatian Road Company, Croatian Highway Company, Croatian National Electricity, local governmental institutes, but MHS is responsible for maintenance, calibration and data quality and data assurance. The configuration of AWSs varies from only wind speed and direction measurement to much more sophisticated measurements, additionally including air temperature, relative humidity, air pressure, see temperature, UV-B radiation and precipitation. AWSs are powered also by solar power supply where electricity is not available. The philosophy of our AWS is to use central processor unit produced and constantly improved by close cooperation of

2 MHS and our domestic electronic company and different sensors of high quality from worldwide well known companies (tab 1). Whole system should meet international and national directives and recommendations adopted by MHS Number of AWSs Year Fig.1 Number of AWSs through decades MHS Costumer Total Fig.2 Network of AWSs of MHS (April, 2006)

3 Nowadays system consists of a central processor unit powered by either the electricity or solar power supply that enables collection of the signal from different sensors. Signals are processed and stored in internal memory as a one second (wind speed and direction) and ten minutes (all others) records in ASCII format. Communication between central processor unit and sensors is available via cable lines or via radio links. Measured data stored as ten minutes records in an internal memory at the station are in different time intervals from 30 minutes to 1 day transferred to the polling computer in Zagreb via telephone lines, GSM or LAN. In the central building of MHS, data are stored in the data base BASE-10 (the base of ten minutes data on the local server) and then transferred via internal network to the server in the central computer, as a safe copy (fig. 3) All the data so collected are available through the program MB-Pregled for the last four days. A direct link from polling computer also enables service communication with every AWS for synchronization, initialization, memory status check, instant data check, manual transfer of the data, averaging interval check. This is very useful before any maintenance is taken. All stations are checked and maintained regularly as well as calibrated according to accepted calibration procedures in Meteorological laboratory. Fig.3 Functioning of the MHS s AWS network

4 Sensor Wind speed and direction (cups) Wind speed and direction (ultrasonic) Air temperature and relative humidity Air temperature and relative humidity Soil and water temperature Sea temperature (buoyant) Air pressure Air pressure Raingauge Raingauge Raingauge Producer Tritonel Multimedia, Croatia Vaisala, Finland Rotronic, Switzerland Vaisala, Finland ThermoFriedrics, Germany Tritonel Multimedia, Croatia Vaisala, Finland Setra, USA Young, USA Meteoservis, Czech Republic Siapp, Italy Solar radiation Table 1. Producers of different sensors used at AWSs in MHS 3. FUTURE Kipp&Zonen, Netherlands Present experience with AWSs and the needs, like increase temporary and spatial coverage, providing data from data sparse areas where human observations are not practical, reduce costs, initiated a modernization of our network. Our aim is to cover all main synoptic stations with at least basic configuration (table 2) of AWS in next two years and in this way assure data for period when our observers do not perform observations. On the stations with higher priorities like observatories we plan to reach standard configuration and on only few, the well extended, additional configuration. Modernization process will be gained in few steps, according to realization of data compatibility assurance, available financial sources and availability of reliable sensors. Next step will be joining of all meteorological data, measured and observed, at the station and then transfer it in one file. This way will assure completeness of the data and reduce transfer costs and needed resources. After reaching this stage there will be a sense to extend measurement program into additional configuration. Concerning the signal transmission, a testing period for implementation of fiber optic line was already started and this year we are going to implement it in the very severe weather conditions, on the station Zavizan (1574 m amsl).

5 MINIMUM CONFIGURATION: - Wind speed and wind direction BASIC CONFIGURATION: - MINIMUM CONFIGURATION - Air temperature - Relative humidity - Precipitation - Air pressure STANDARD CONFIGURATION: - BASIC CONFIGURATION - Insolation - Global solar radiation - Diffuse solar radiation - Soil temperature - Water temperature - UV radiation - Surface ozone ADITIONAL CONFIGURATION: - STANDARD CONFIGURATION - Evaporation - Visibility - Snow height - Soil state - Cloud base height - Present weather Table 2. Different configurations of AWSs in MHS 4. CONCLUSION Properties of our automatic weather stations enable to integrate them into all type of monitoring (ecological, electricity, traffic, tourism) i.e. operative following and warning of possible severe weather conditions. Nowadays our main focus is to cover all representative places in Croatia for synoptic and climatologic purposes with AWSs measurement, to extend all measurements to minimal 5 parameters per AWS and to improve sampling rate and data quality to meet more costumer s needs.

6 References 1. Penzar, B et al: Meteorologija za korisnike, Školska knjiga, Zagreb, Žibrat, Z., Dvornik, A., 1998: Meteorološki monitoring za potrebe poljoprivrede i šumarstva, Znanstveni skup s međunarodnim sudjelovanjem "Prilagodba poljoprivrede i šumarstva klimi i njenim promjenama", Zagreb, , str Pandžić, K. i suradnici, 1998: 50 godina rada Državnog hidrometeorološkog zavoda , DHMZ, Zagreb, 1998, 288 str. 4. Pandžić, K. Et al, 2002: 150 years of meteorological observations in Croatia, MHSC, Zagreb, 2002, 193 p.