Publications by authors named "Yonggang Jia"

5 Publications

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Author Correction: Deep-sea Sediment Resuspension by Internal Solitary Waves in the Northern South China Sea.

Sci Rep 2019 Nov 21;9(1):17522. Epub 2019 Nov 21.

Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, P.R. China.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41598-019-53956-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6868124PMC
November 2019

Deep-sea Sediment Resuspension by Internal Solitary Waves in the Northern South China Sea.

Sci Rep 2019 08 20;9(1):12137. Epub 2019 Aug 20.

Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, P.R. China.

Internal solitary waves (ISWs) can cause strong vertical and horizontal currents and turbulent mixing in the ocean. These processes affect sediment and pollutant transport, acoustic transmissions and man-made structures in the shallow and deep oceans. Previous studies of the role of ISWs in suspending seafloor sediments and forming marine nepheloid layers were mainly conducted in shallow-water environments. In summer 2017, we observed at least four thick (70-140 m) benthic nepheloid layers (BNLs) at water depths between 956 and 1545 m over continental slopes in the northern South China Sea. We found there was a good correlation between the timing of the ISW packet and variations of the deepwater suspended sediment concentration (SSC). At a depth of 956 m, when the ISW arrived, the near-bottom SSC rapidly increased by two orders of magnitude to 0.62 mg/l at 8 m above the bottom. At two much deeper stations, the ISW-induced horizontal velocity reached 59.6-79.3 cm/s, which was one order of magnitude more than the seafloor contour currents velocity. The SSC, 10 m above the sea floor, rapidly increased to 0.10 mg/l (depth of 1545 m) and 1.25 mg/l (depth of 1252 m). In this study, we found that ISWs could suspend much more sediments on deepwater areas than previously thought. Specifically, we estimated that ISWs could induce and suspend 78.7 Mt/yr of sediment from shelf to deep-sea areas of the northern South China Sea. The total amount of sediment resuspended by shoaling ISWs was 2.7 times that of river-derived sediment reaching the northern South China Sea. This accounted for 6.1% of the global river-discharged sediment (16.4% of that from Asian rivers) transported to the sea.
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http://dx.doi.org/10.1038/s41598-019-47886-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6702154PMC
August 2019

A Seabed Real-Time Sensing System for In-Situ Long-Term Multi-Parameter Observation Applications.

Sensors (Basel) 2019 Mar 12;19(5). Epub 2019 Mar 12.

Key Laboratory of Marine Environment and Geological Engineering Shandong Province, Ocean University of China, Qingdao 266100, China.

Aiming at the real-time observation requirements in marine science and ocean engineering, based on underwater acoustic communication and satellite communication technology, a seabed real-time sensing system for in-situ long-term multi-parameter observation applications (SRSS/ILMO) is proposed. It consists of a seabed observation system, a sea surface relay transmission buoy, and a remote monitoring system. The system communication link is implemented by underwater acoustic communication and satellite communication. The seabed observation system adopts the "ARM + FPGA" architecture to meet the low power consumption, scalability, and versatility design requirements. As a long-term unattended system, a two-stage anti-crash mechanism, an automatic system fault isolation design, dual-medium data storage, and improved Modbus protocol are adopted to meet the system reliability requirements. Through the remote monitoring system, users can configure the system working mode, sensor parameters and acquire observation data on demand. The seabed observation system can realize the observation of different fields by carrying different sensors such as those based on marine engineering geology, chemistry, biology, and environment. Carrying resistivity and pore pressure sensors, the SRSS/ILMO powered by seawater batteries was used for a seabed engineering geology observation. The preliminary test results based on harbor environment show the effectiveness of the developed system.
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http://dx.doi.org/10.3390/s19051255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6427298PMC
March 2019

Study on diesel vertical migration characteristics and mechanism in water-bearing sand stratum using an automated resistivity monitoring system.

Environ Sci Pollut Res Int 2018 Feb 24;25(4):3802-3812. Epub 2017 Nov 24.

Qingdao Institute of Marine Geology, China Geological Survey, Qingdao, China.

Oil spills frequently occur on both land and sea. Petroleum in mobile phase will cause serious pollution in the sediment and can form a secondary pollution source. Therefore, it is very important to study the migration of petroleum in sediments ideally in a rapid and simplified approach. The release of diesel was simulated using fine beach sand to construct a model aquifer, and dynamic monitoring was carried out using an automated monitoring system including a resistivity probe originally developed by our research group. The mobile phase migration fronts were determined accurately using wavelet analysis method combined with resistivity curve method. Then, a relationship between resistivity and the joint oil-water content was established. The main conclusions were as follows. The seepage velocity of the diesel with high mobility at the initial stage of infiltration was faster, followed by a period when gravity seepage was dominant, and finally a redistribution period at the later stage, which was mainly an oil-water displacement process. The resistivity trends for diesel infiltration in different water-saturated soil layers varied with depth. The resistivity in the vadose zone fluctuated significantly, increasing initially and later decreasing. The resistivity change in the capillary zone was relatively small and constant in the initial stage; then, it increased and subsequently decreased. The resistivity in the saturated zone was basically unchanged with depth, and the value became slightly larger than the background value over time. Overall, for a large volume of mobile phase diesel leakage, the arrival migration fronts can be detected by wavelet analysis combined with resistivity curves. The thickness of the oil slick in the capillary zone can be estimated by resistivity changes. The relationships between resistivity and both the moisture content and oil-water joint saturation are in agreement with the linear models. The research results provide basic data and a new data processing method for monitoring of contaminated sites following major oil spills using the resistivity method.
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http://dx.doi.org/10.1007/s11356-017-0698-3DOI Listing
February 2018

A case study to detect the leakage of underground pressureless cement sewage water pipe using GPR, electrical, and chemical data.

Environ Sci Technol 2002 Mar;36(5):1077-85

Department of Environmental Engineering, College of Geoscience, Ocean University of Qingdao, Shandong, PR China.

The exploration and determination of leakage of underground pressureless nonmetallic pipes is difficult to deal with. A comprehensive method combining Ground Penetrating Rader (GPR), electric potential survey and geochemical survey is introduced in the leakage detection of an underground pressureless nonmetallic sewage pipe in this paper. Theoretically, in the influencing scope of a leakage spot, the obvious changes of the electromagnetic properties and the physical-chemical properties of the underground media will be reflected as anomalies in GPR and electrical survey plots. The advantages of GPR and electrical survey are fast and accurate in detection of anomaly scope. In-situ analysis of the geophysical surveys can guide the geochemical survey. Then water and soil sampling and analyzing can be the evidence for judging the anomaly is caused by pipe leakage or not. On the basis of previous tests and practical surveys, the GPR waveforms, electric potential curves, contour maps, and chemical survey results are all classified into three types according to the extent or indexes of anomalies in orderto find out the leakage spots. When three survey methods all show their anomalies as type I in an anomalous spot, this spot is suspected as the most possible leakage location. Otherwise, it will be down grade suspected point. The suspect leakage spots should be confirmed by referring the site conditions because some anomalies are caused other factors. The excavation afterward proved that the method for determining the suspected location by anomaly type is effective and economic. Comprehensive method of GRP, electric potential survey, and geochemical survey is one of the effective methods in the leakage detection of underground nonmetallic pressureless pipe with its advantages of being fast and accurate.
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http://dx.doi.org/10.1021/es001954sDOI Listing
March 2002
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