18 Weather Monitoring
The IRGASON is the latest development in Campbell Scientific's micromet range and is a natural progression from the EC150/EC155 gas analysers and CSAT3A head released a couple of years back. These devices were designed to operate and physically connect together to closely co-locate measurement volumes, minimise air flow distortion and, because they also connect to the EC100 electronics unit, benefited from reduced system power and complexity and pre-logger temporal data synchronisation.
Whilst clearly anybody setting up an EC system from scratch would want the extra benefits of the IRGASON, the separate EC150 Open Path IRGA is still available for anybody that has an existing Campbell CSAT3 sonic anemometer or who wishes to use a sonic of another make. (Using the EC150 with another make of anemometer clearly would not co-locate the measurement volumes in the same manner).
Closed Path Eddy Covariance – CPEC200
CPEC200 - The CPEC200 is a fully integrated, turn-key closed-path Eddy Covariance system.
As well as open path systems Campbell Scientific also offer the CPEC200 closed path system. Closed path has some advantages over open, it can be used when it is raining for one thing, but typically such systems are more complex to install and more costly. The CPEC200 is an integrated closed-path Eddy Covariance system which consists of an EC155 closed-path gas analyser, the CSAT3A sonic anemometer and a pre- programmed CR3000 data
logger. The system also includes a pump module, the CPEC200 enclosure and all the necessary mounting hardware, tubing and cables. An optional valve unit is available for automated zero and span. As mentioned above the CSAT3A sonic anemometer and EC155 gas analyser are designed to mount directly together, closely co-locating the measurement volume of both instruments, minimising air flow distortion and utilising shared electronics for simplicity of installation and power efficiency.
The EC155 closed-path gas analyser samples the air directly in the head of the instrument minimising any 'mixing' associated with systems where the sample is pumped from the intake to a separate analyser unit sometimes some metres away. The sample intake is heated to prevent condensation and the instruments small sample cell volume (5.8 ml) minimises the sample residence time (50 ms at the system’s nominal flow rate, 7 LPM). This gives excellent frequency response (5.8 Hz half-power bandwidth).
The systems fundamental measurement frequency is 100 Hz with a user-selectable output bandwidth at 5, 10, 12.5, 20 or 25 Hz. Data can be stored on-board using CompactFlash cards up to 2 Gb, enough to record up to 2 months of data at 10Hz, or the system can be remotely interrogated with telemetry methods including Ethernet, RS-232, short haul modem, land-line and RF wireless, cellular and satellite. Overall system power is just 12W meaning that the CPEC200, like the open path IRGASON, can also be powered by solar panels in many situations.
The data logger program brings together all the components of an Eddy Covariance system and Campbell Scientific offer a library of CRBasic programmes which can be used for an Eddy Covariance station either with or without energy balance sensors.
AP200 – CO2& H2O Profiler Often used in conjunction with an eddy covariance system the AP200 is a complete, integrated CO2 and H2O atmospheric profile
system which measures the storage term and give a more complete measure of the surface gas
exchange. It measures carbon dioxide (CO2) and water vapour (H2O) concentration from up to eight intakes, which are normally spaced
along the height of a tower to give a vertical profile.
AP200 - The AP200 is an atmospheric
profiling system measuring CO2& H2O concentrations from up to 8 intakes
The AP200 contains a pre- programmed CR1000 measurement and control datalogger which takes the measurements but also automates zero and span and automates the temperature and pressure control. The whole system requires just 13W (average at 25°C and 12 Vdc).
Conclusion
Campbell Scientific has been involved in micrometeorological instrumentation for many years and these latest devices are the result of ongoing commitment to product development and innovation in this area. Campbell Scientific believe that the introduction of these low power, turnkey systems, with their co- located measurement volumes will make it easier for scientists to concentrate more on taking and analysing good measurements and have to worry a little less about the instruments.
Meteorological Monitoring System
The Met Office, providers of environmental, weather and climate services currently operate a network of manual, automatic and semi-automatic meteorological measuring and observing sites at more than 280 locations in the United Kingdom and a small number overseas, for real-time data acquisition.
CSE Servelec (UK) has provided an enterprise SCADA solution as the backbone of their Meteorological Monitoring System (MMS).
The MMS replaced several previous legacy systems and allows data from meteorological sensors to be gathered and stored at the Met Office headquarters in Exeter. The system enables the Met Office to carry out data processing and analysis centrally in a flexible and manageable way. The observations are fundamental to almost all the services the Met Office provides - as direct data and products; for initialising numerical weather prediction models; for verification of forecasts; as the basis for many weather/climate related consultancy services; and for providing evidence of climate change.
More frequent data sampling, additional data from existing sensors, or the addition of new sensors is made possible with the MMS. This versatile and scalable observing infrastructure allows operational and maintenance costs to be reduced, as well as technical risks. Data is delivered to a modularised central processing system enabling a more efficient management and support structure.
System inputs, such as radiation, air quality or hydrology can be fully integrated. The system is also dynamic and adaptable to customer needs, for example frequency and quality can be altered.
The MMS is based on CSE Servelec's well-established Telemetry and SCADA application suite, SCOPE-X.
SCOPE-X implements a fully redundant duplicated real-time database seamlessly united to an Oracle long-term historic database and flexible data interfaces.
SCOPE is a family of products that meets current and future requirements for SCADA and Telemetry systems. SCOPE provides non-stop monitoring and utilises high levels of redundancy, reliability and robust software design to offer high availability and low maintenance requirements.
The real-time integration of data into management information systems allows users through the business to access data for making informed and independent decisions.
Flexible system architectures meet the requirements of a range of applications, from a simplex single site SCADA to enterprise wide systems.
The client application is browser-based and provides a fully functional user interface supplying the tools and utilities necessary to configure, maintain and operate the system.
SCOPE-X is widely used in the Utility sectors and in some more specialised sectors for wide area applications.
CSE Servelec's current list of blue chip users of SCOPE-X includes BAA/Heathrow, British Broadcasting Corporation - BBC Transmission (now NGW) and BBC World Service, National Grid Gas, Welsh Water, Southern Water, Wessex Water, Trinity House and the Environment Agency.
Reader Reply Card No. Reader Reply Card No. 61 IET May / June 2012
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