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Information and Telecommunication Network |
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The integrated telecommunication network was established in 1997 by CMA, which is based on satellite telecommunication (satellite based sub-system) and supplemented by public telecommunication system. The network system consists of 1 national hub and 31 provincial stations. The former is located in the building of National Meteorological Center, while the latter are distributed in the various provincial meteorological bureaus. In addition, the system is attached with 297 stations of prefecture level and nearly 2000 satellite receiving stations (receiving only). They are all located in the meteorological service below provincial level across the country. The satellite based sub-system is further divided into 3 parts namely satellite data communication network, satellite telephone communication network and one way satellite data broadcast system.
The satellite data communication network is used as a multiple port bridge router, which interconnects the computer local area network in the national data control center with more than 300 computer local area networks scattered in the meteorological services of different levels throughout the country, and forms a computer wide area network. The daily data volume transmitted on this network reaches several hundreds of megabit. At present, the out bound rate of satellite data communication network is 512Kbps, the in bound rate is 64Kbps and 128Kbps respectively.
The group exchange network rented from China Telecom is used as a back up for satellite based sub-system. In case of accident, the up link data flow could be switched to group exchange network, which can ensure the continued up link real time data transmission.
The satellite telephone network could be used to hold nation wide telephone conference, which has played a very important role in coordinating flood relief and other disaster reduction activities.
The one way satellite data broadcast system is the main channel for CMA to distribute guidance products to meteorological service at different local levels. The band width of this system is 2Mbps. At present, the data volume broadcasted every day is 400 to 600 megabit. The system can provide 1.2Mbps video broadcast capability while data is being broadcasted. In connection with satellite telephone network, it can be used for television conference and distance learning.
The one way satellite data broadcast system is operated on Ku transponder of Asia Satellite 2 which corers not only China but also its neighboring countries. Necessary facilities have been installed in Mongolia and DPRK to include the meteorological service in both countries in the system.
Beijing is one of RTHs of Global Telecommunication System of WMO. The switch system in RTH Beijing is based on DEC System. Since its establishment in 1980's, its equipment has been up grated several times, thus its telecommunication capabilities have been steadily improved. Up to now it has established dedicated meteorological circuits with 12 WMO Members. The data volume exchanged every day with outside of China is about 43 MB.
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