| 2005 |
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YEAR BOOK |
Met �ireann
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Borealis TV Graphics System
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The Borealis System
Borealis is the most recent upgrade in a succession of graphical software packages which have been used on RT� Weather. Its purpose is the same as that of its predecessors � to present a weather "message" which is accurate, informative and attractive to viewers.
Borealis presents basic weather information from Met �ireann's limited-area atmospheric model (HIRLAM), and longer-range forecast data from the European Centre for Medium-Range Weather Forecasts (ECMWF). Satellite imagery comes from the European Meteosat family of weather satellites, and radar data from both the UK/Irish co-ordinated network and the high-resolution Met �ireann network. Images from the American NOAA series of polar-orbiting weather satellites can also be displayed.
The task of exploiting the Borealis system to make all this information comprehensible and visually attractive falls to a collaboration between RT�'s graphics artist and Met �ireann's software specialist. The graphics artist creates the "look and feel" of the weather presentation � designing the background maps, the various weather symbols (for temperature, wind etc.), the font style, size of text and so on. The software specialist implements the graphic artist's designs, using the flexibility built into the Borealis system to depict the varying states of the weather. A whole host of issues must be addressed � at what rates of rainfall do we show the symbols for light, moderate or heavy rain? At what values should the temperature symbols be coloured blue, yellow or red? How do we best adjust the appearance of satellite images through the year, from winter (when the sun is low on our horizon, and consequently satellite images over northern Europe have low illumination) to summer?
The Technical Infrastructure
The Borealis system runs on a PC. However when the PC is broadcasting directly to air, supporting a vital public service such as the weather forecast, then a standard off-the-shelf machine will not suffice. Security and reliability are of paramount importance and are achieved through redundancy. Met �ireann has installed two separate "SuperMicro" computers in RT� to service the weather studio. Each PC has three distinct power supply units; two can fail and the machine will continue to run with the remaining operational unit. There are four 120 Gigabyte hard disks, configured as a redundant array of independent disks (RAID), giving total disk space of almost half a Terabyte. The disks work in pairs, with each pair capable of running the system independently. Thus one, and possibly two disks can fail with no noticeable impact on operations.
Each of the weather graphics computers comes equipped with 2 Gigabytes of random access memory (RAM), and a Nvidia GeForce4 Graphics card with 256 Megabytes of on-board memory. Borealis makes use of the same graphics facilities as in leading-edge video games, together with a digital video (DV) card which generates the broadcast quality digital video signal. The system has two 2.4 Gigahertz Intel Zeon processors; one of these is needed to run the DV card when the system is on-air. The computers, physically located in an air-conditioned rack room close to the weather studio in RT�, are connected to Met �ireann's central computer facility in Glasnevin through a 512 Kbps fixed link.
Simply the best
The response to Borealis from the Irish public � an especially discerning audience for weather information � has been very positive. Ireland is large enough to allow a variety of different weather types to co-exist at any given time, yet each viewer expects a description of what the weather will be like in their locality for the coming days. To present this variety of complex, highly-detailed information � in effect, a series of different weather stories to viewers in different parts of the country � in just two minutes of air time would be impossible without fully exploiting all possible means of visual communication. Only the best is good enough and, in using the Borealis software, Met �ireann and RT� employ one of the world's foremost graphics systems to illustrate some of the world's most interesting weather.
Contact: Gerald Fleming, General Forecasting Division,
Met �ireann, Glasnevin Hill, Dublin 9.
E-mail: [email protected]