Sea Technology

SEP 2012

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junction box will have more than 10 universal waterproof plugs for sensors and one optical fiber plug for connecting the backbone cable. The universal waterproof plugs will be able to output 12, 24 and 48 DC voltages and will be remotely controlled to meet the needs of different types of instruments in the control center lab or shore station. Other instruments to be installed in the observatory include sen- sors for physical oceanography, such as ADCPs and tide and wave gauges, and devices for measuring CTD, pH, chloro- phyll, dissolved oxygen, colored dissolved organic matter, rhodamine and CO2 . Other marine geochemical sensors will be added, as well as geological and geophysical equipment, such as a turbidity sensor (optical backscatter point sensor) and ocean-bottom seismographs. A CO2 stalled on the top of the platform to measure sea-surface at- mospheric CO2 (Top) The observatory's landing plat- form. (Right) The observatory's remote con- trol and visual information system. In-situ data are continuously trans- mitted through the junction box and fiber-optic cables to the platform, then wirelessly sent to a receiver lo- cated in the State Key Laboratory of Marine Geology at Tongji University in Shanghai. For the first several months of the observatory's operations, the sam- pling rate of the ADCP and CTD was once per minute, and the spatial reso- lution was 25 centimeters. From Oc- tober 2009, the frequency of ADCP and CTD data transmission shifted to 15-second intervals. The information received at Tongji University includes near- bottom temperature, conductivity, pressure, turbidity, cur- rent values and directions (in discrete layers of 25 centime- ters per layer from 80 centimeters above the seafloor to the sea surface), and status parameters of all equipment. Preliminary observation results show that the current field and fine suspended sediment transport of the East Chi- na Sea are complex and show considerable seasonal varia- tion, affected by the influence of Changjiang's diluted water, Taiwan's warm current and the Yellow Sea coastal current. Observatory Upgrades The upgrade project will transform the observatory into an integrated observation station and test bed in four stages, all of which began in October 2011. In-situ measurements of the upgraded seafloor obser- vatory will be used to monitor physical and sedimentary processes, such as variations in turbidity and sediment de- position rates in the Yangtze River and the East China Sea Shelf, and to study responses of the ocean environment and ecosystem to extreme weather, such as earthquakes and tsu- namis, and climate changes. In the first stage of the upgrade, completed at the end of August, a common-use junction box will be designed to realize plug-and-play for general ocean sensors. The new sensor will be in- concentration for comparison with seafloor observation sensor data. The second step of the up- grade, to be completed in December, is to accomplish a series of reconstruction work. The observatory will rely on so- lar energy to meet sensors' in- creasing power needs. Due to the low conversion rate of the solar panels, a few more solar panels will be added to the top of the platform's edge, and a windmill will also be installed. The platform's communication and remote control equipment will be upgraded to handle the large number of data wirelessly transmitted. The trawl pre- venter will also be modified for the common-use junction box and all the sensors. The third step in the upgrade is to set up cyber infrastruc- ture, which will be a long-distance controlling visual subsys- tem for remotely operating sensors. A geographic informa- tion subsystem for applications and an observation database will also be designed. The architecture of the visual information system will consist of the information flow from data collection, orga- nization, management and sharing, as well as modeling ap- plications. It will have a complete information processing link and will be divisible into four functional modules. The first will be a data-receiving module, which will fulfill data reception, decoding and database storage and management. The second module will be for information, instrumental status and data quality control. The third module will be a two-dimensional GIS, which will perform metadata man- agement for the observation data, and query and statisti- cal analysis. The fourth module will be a 2D or 3D linkage module, which will primarily fulfill 2D or 3D modeling for visualization applications. All the modules will be designed according to .NET, a standard component that can be run separately or together. All the modules will be capable of connecting seamlessly with the SQL Server 2005 database system for operational efficiency. The fourth step of the upgrade, to be completed after the trial run of the observation system, is to create criteria for the www.sea-technology.com SEPTEMBER 2012 / st 57

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