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Coastal Marine Environment Monitoring In Great Wall Cove
Upgraded System in China Transmits Real-Time Data from Antarctic

AUTHORS:


Xiangnan Wang

Changlei Ma



Deployment of the NMEMS in Great Wall Cove.
The Fildes Peninsula of King George Island is one of the regions experiencing the fastest temperature rise in the Antarctic. The meteorology data from 1985 to 2008 indicate that the air temperature variability is 0.27° C every 10 years, showing an obvious climate warming trend. Meanwhile, the biota and biodiversity in King George Island is abundant. Thus, the new-generation marine environment monitoring system (NMEMS) developed by the National Ocean Technology Center of China was deployed in Great Wall Cove to monitor the marine environmental and ecological parameters. The data will help to study the response of the Antarctic ecosystem to global climate change.

The Great Wall Cove located in the southeast of Great Wall Station is a semienclosed bay with a 35-meter maximum depth. The cove is affected by the current beyond it and the land-based thaw instreaming. The continuous temperature, salinity, chlorophyll (CHL) and other data for several seasons, combined with historical data, will be important for studying the Antarctic ecosystem.


NMEMS
The prototype of the NMEMS is the polar coastal marine environment monitoring system, known as PCMEMS, which was deployed in 2009 and 2010. The new system consists of the underwater monitoring subsystem, the data transmission subsystem and the power subsystem.

The underwater monitoring subsystem consists of two Sea-Bird Electronics Inc.ís (Bellevue, Washington) SBE 16 CTDs, a Sea-Bird Electronics SBE 37 CTD, a Teledyne RD Instruments (Poway, California) WHM600 acoustic Dopler current profiler (ADCP) and a pair of EdgeTech (West Wareham, Massachusetts) acoustic releasers mounted on the bottom framework. The instruments are arranged as follows from the bottom up: the SBE 37 CTD, releaser, ACDP, SBE 16 CTD and buoy. The measurement data, including CTD, pH, CHL and current, are saved in the control cabin and transmitted in real time to the data transmission subsystem via the cable. The upgraded control cabin contains an interface designated for communication with another self-contained underwater monitoring system to form an underwater monitoring network.

The power subsystem contains an armored cable, providing power supply for the system from the coastal station. Serial RS485 communication technology is used to transmit the data collected by the underwater monitoring subsystem. The cable through the intertidal zone is buried to avoid the effects of tide and ice. The data transmission subsystem can receive data at an interval of 30 minutes and transmit the compressed data via satellite daily.


PCMEMS
The prototype system, PCMEMS, was deployed in the Great Wall Cove in 2009 and 2010 and operated for four months and five months, respectively. The acquired data were used to inform a system upgrade.

With a higher networking ability and improved survivability, the NMEMS was deployed in Great Wall Cove in January 2012 during the 28th Chinese National Antarctic Research Expedition and has been operating for more than nine months. The NMEMS acquired more than 13,000 groups of data at 30-minute intervals up to October 17, 2012. The data have been preliminarily analyzed.


Environmental Variables
The range of temperature and salinity change is -1.92 to 2.67° C and 33.51 to 34.26, respectively. The temperature fluctuated between 1 and 3° C until March 2012, and then declined sharply during April. The two peak values occurred on January 31 and February 9, 2012. The temperature declined to around -2° C at the end of May. The temperature variation trends in the upper layer, middle layer and bottom layer are well-correlated: The linear regression correlation factor of upper-middle, upper-bottom and middle-bottom is 0.987, 0.965 and 0.991, respectively. To continue this article please click here.



Xiangnan Wang received his B.S. degree in precision instrument and optoelectronics engineering from Tianjin University in 1987. He is now a professor at the National Ocean Technology Center of China and has been active in various aspects of the research and design of marine environmental and ecological monitoring systems since 1987.

Changlei Ma received his B.S. degree in marine management from the Ocean University of China in 2003 and his M.S. degree in marine monitoring technology in 2010. His research interests include marine strategy and the application and integration of oceanographic sensor platforms.







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