A Look at the Supports and Needs in the Advancements of Marine Monitoring Technology for the Past Decade

Marine environmental monitoring technology is one of the key subjects of the High Technology Research and Development Program in China, and has been implemented for more than IO years. During that time, there has been a great change in marine monitoring and surveying technology.
This article presents the current situation and development of marine monitoring technology in China for the past decade, including marine dynamic environmental monitoring, marine ecological environmental monitoring system integration and its pilot application.

Dynamics Monitoring
The study and development of automatic observation technology in shore-based marine hydrography and meteorology make it possible for monitoring instruments Io be manufactured as a complete series sensor to devices and systems. For example, a study on a high-accuracy conductivity, temperature, depth (CTD) profiler measuring technology can lead to the development of a self-contained CTO profiler and direct-reading CTD profiler with a maximum designed applied depth of 6.000 meters, and a maximum actual applied depth of more man 5.000 meters. The accuracy range of a temperature-measuring thermistor is within ±0.003° C. the accuracy range of conductivity with a three-electrode cell reaches ±0.003 square meters per centimeter. In addition, a CTD sealing and testing laboratory can be set up, with the temperature fluctuation field and the temperature Held uniformity in the constant temperature water baths being controlled within ±0.0003° C.

With further studies of the high-frequency ground wave measurement technology of radar on sea surface dynamic environmental parameters, t\ui kinds of samples in single and high-frequency ground wave radar-with detecting distances of 200 kilometers and 370 kilometers, respectively-have been developed. Tests at tlxed points in the sea were carried out by applying the single or double-radar samples, with the distribution pattern of the radial current vectors during a storm plotted. The maximum measuring distance by a medium-range radar is 200 kilometers for sea current and direction of wind and 150 kilometers for wave height and wind velocity, among which the measuring error for the current velocity is three to six centimeters per second with the error for current direction at ±20°.

The maximum measuring distance by a long-distancerange radar is not less than 370 kilometers for sea current and wind direction and not less than 180 kilometers for wind velocity and wave height. The measuring error for velocity is 12 to 20 centimeters per second and is ±20° for current direction.

The studies of the profiling drifter have lead to the development of a round disk-type of multi-parameter anchor buoy China's Ocean Profiling Fxplorer (COPFX) oceanic optical buoy. The large floating device, integrated with a multi-clement measuring system, as a universal oceanic environmental observation and tesi platform make real-time monitoring of oceanic meteorological and hydrological profiles and the optical environment of the micro-scale process that occurs in the ocean-atmosphere interface possible.

The thrce-meter-diamcter anchor buoy, with flexible tethered structure and underwater observation data-induced coupling transmitting system, can monitor me meteorological and hydrological parameters al the sea's surface, such as surface water temperature, salinity, height and period of waves, and current profiles. To date. 14 experiments have been carried out by COPHX. with a maximum profile depth of 1,969 meters. More than 67 profiles have been measured, looking at the ocean surface, ocean subsurface and cuphotic layer.

With the study and development of automatic seabedbased oceanic emironmenlal monitoring technology, monitoring systems for the suspended sand in the sea bed and its dynamic background, and systems for monitoring the marine dynamic environment in the sea bed were then developed in sequence. The former system can he used to measure the dynamic environmental parameters and concentration profile of suspended sediments, including particle-size spectra. With a 24-bollle water sampler, the system can collect at regular time intervals, which can he applied to port engineering and river channel dredging.

The latter system can only be applied to the measurement of the dynamic environment, and the underwater data can be transmitted back to a shore station or nearby floating buoy by a wireless communication system, or it can be downloaded alter the system is collected.

Eco-Monitoring
The study of chemical oxygen demand (COD)-measuring technology is mainly focused on the development of COD-measuring techniques for the flow injection method of potassium permanganate and the c he mi luminescence method by gas phase ozone. For this, two types of sample instruments were developed. One instrument uses potassium permanganate as a strong oxidation agent bused upon the chcmiluminescence principle when the interaction between the gases phases ozone and the organic pollutants into the water samples.

The other instrument was developed Io measure the photolumineseence spectra of organic material and to identity the property and content of the pollutants. Thus, the COD value of the water sample can subsequently be determined, with a detection limit of 0.5 milligrams per liter with no additional chemical reagents needed.

Therefore, there will be no second time pollution, and the question of the accuracy of the test due to the high content of chlorine ion in the water can be avoided.

Biological oxygen demand (BOD) measuring technology is focused on the development of two types of instruments for the rapid measurement of seawater. One type is a sea water rapid BOD using the biological oxygen balancing method, and the other is a fiber optic BOD, whose testing time for a single point is much better than that by using the traditional five-day method. A common trait of the two methods is that sail-resistant fungus and good adaptability are both needed, since the measuring precision is directly associated with the biological activity of the fungus and the precision of the oxygen sensor.

The automatic analyzer of nutrition salts was developed through a study at the Micro-Systems and Control Lab. Total operations and analyses - such as sampling, chemical agent filling-in, chemical reaction, temperature controlling and heating, light absorption measurement and data processing and storage - can be automatically completed.

Thus, two types of analyzers have been developed: one is an atomic analyzer of nutrition salts made on the basis of the light absorption method, and the other was created on the basis of the automatic reference of flow colourimetry. The former can measure five different parameters of nutrition salts in the sea water, with a processing time of no more than 20 minutes, and is suitable for discontinuous measurement. The latter is suitable for successive measurements because the samples are input by the flow injection mode.

System Integration
The Integrated Marine Environmental Monitoring System at the Changjiang River Estuary is piloted by the city of Shanghai, China. The Marine Environmental Pollution Monitoring System at the Pearl River Estuary provides great support for the social development of the economic zones and construetion of the moderni/ed harbor city of Shanghai. Moreover, along the Fujian coast, the real-time and 3D marine dynamic environmental monitoring system for the Taiwan Strait and abutting sea areas lias also been established. That system supports the development of coastal areas in China's Fujian and Southern Zhejiang provinces, and also contributes to disaster prevention and mitigation.

Along the Bohai coastal areas, the North China Sea Branch of the State Oceanic Administration is developing a shiphorne quick, and integrated monitoring system for oceanic ecological environment. It is one of the organic parts of the near-real-time, 3D ecological environmental monitoring pilot system for the Bohai Sea. The system will work to improve the flexible and rapid monitoring capacity for the Bohai Sea eco-environment, and support the development of the Bohai economic zone.

Conclusions
These quick, real-time and dynamic monitoring techniques provide the greatest support for human activities all over the ocean. The authors of this article are very confident that the development of these marine monitoring techniques will provide a better technical equipment and information platform for marine environment administration, better protection and disaster monitoring, and better production for naval forces. It will also be seen that this development shall provide reliable support for the ocean economy.