Wensheng Jiang | Ocean University of China (original) (raw)
Papers by Wensheng Jiang
Journal of Marine Systems
Measurement Science and Technology
Journal of Ocean University of China
Journal of Oceanology and Limnology
International Journal of Applied Earth Observation and Geoinformation
Journal of Geophysical Research: Oceans
Journal of Ocean University of China
Laser in situ scattering and transmissometry (LISST) significantly improves our ability to assess... more Laser in situ scattering and transmissometry (LISST) significantly improves our ability to assess particle size distribution (PSD) in seawater, while wide-ranging measurements of the organic-inorganic compositions of suspended particulate matters (SPM) are still difficult by using traditional methods such as microscopy. In this study, PSD properties and SPM compositions around the Bohai Strait (China) were investigated based on the measurements by LISST in combination with hydro-biological parameters collected from a field survey in summer 2014. Four typical PSD shapes were found in the region, namely right-peak, left-peak, double-peak and negative-skew shapes. The double-peak and negative-skew shapes may interconvert into each other along with strong hydrodynamic variation. In the upper layer of the Bohai Sea, organic particles were in the majority, with inorganic particles rarely observed. In the bottom layer, SPM were the mixture of organic and inorganic matters. LISST provided valuable baseline information on size-resolved organic-inorganic compositions of SPM: the size of organic particles mainly ranged from 4 to 20 µm and 40 to 100 µm, while most SPM ranging from 20 to 40 µm were composed of inorganic sediment.
Continental Shelf Research
Continental Shelf Research
Biogeosciences Discussions, 2016
In a stratified water column, the nitracline is a layer where the nitrate concentration increases... more In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not well established. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions for the system of phytoplankton and nutrient. The analytical solution shows that the nitracline depth is deeper than the depth of SCML, shoaling with an increase in light attenuation coefficient and...
Journal of Ocean University of China, 2016
Cont Shelf Res, 2008
Salinity is an important component of the marine system. Previous studies indicated that the mean... more Salinity is an important component of the marine system. Previous studies indicated that the mean salinity in the Bohai Sea had increased by 2.0psu in the second half of the 20th century, mainly due to a sharp decrease in the Yellow River runoff, and also the effects of large-scale climatic variations and the intrusions of the North Yellow Sea Water
International Journal of Applied Earth Observation and Geoinformation, Sep 1, 2010
Study of suspended particulate matter (SPM) transport in a coastal area, traditionally supported ... more Study of suspended particulate matter (SPM) transport in a coastal area, traditionally supported by field observation and numerical simulation, benefits now from numerous available remotely sensed ocean color images. Numerical simulation of SPM dynamics can be the supplement to remote sensing data which response the discrete states for different point-in-times. It would be helpful for monitoring coastal water environment in a real sense if remote sensing can be coupled with numerical simulation to get a promising water environmental dynamics in time and space domain. In this study, an approach coupling ocean color image retrieval with numerical simulation of SPM transport is proposed. Instead of traditionally specifying the spatial-constant SPM concentration as an initial condition of sediment transport models, the spatial-variant SPM concentration retrieved from MERIS image initializes the models. And the SPM resuspension and deposition can be interactively inspected and verified. Combining the simulated results with the remote sensing retrieved results, the parameters of hydrodynamic model and sediment transport model can be calibrated. The Bohai Sea in China is selected to test the approach. An optimized group of parameters are calibrated by using the SPM concentration retrieved from MERIS image in the Bohai Sea. Compared with the SPM initialization of spatial-constant, the spatial-variant SPM input retrieved results can quickly response to the changes of sediment concentration in real sense. The results show a well agreement with the in situ measurements. The results show that the approach is good at simulating SPM dynamics in clear waters with a SPM concentration lower than 20 mg/l and more effective in the area with less land source affected. The study suggests that the proposed approach is effective for monitoring coastal water environment roundly and three-dimensionally.
Journal of Geophysical Research: Oceans, 2013
A regional ocean circulation model (ROMS) is used to simulate the Chinese landderived sediment tr... more A regional ocean circulation model (ROMS) is used to simulate the Chinese landderived sediment transport in the Bohai Sea, Yellow Sea, and East China Sea (BYECS). The model includes the effect of currents, tides, and waves on the sediment transport and is used to study the pathway and dynamic mechanisms of the fine-grain sediment transport from the Huanghe River (Yellow River), the Old Huanghe Delta, and the Changjiang River (Yangtze River) in the BYECS. The seasonal variability of the sediment transport in the BYECS and the sources of the Yellow Sea Trough mud patch, the mud patch southwest of Cheju Island, the mud patch offshore from the Zhejiang and Fujian provinces and the Okinawa Trough mud patch are discussed. The results show that the Huanghe River sediment can be transported to the Yellow Sea Trough, but little makes it to the outer shelf while the Old Huanghe Delta sediment is mainly transported to the Yellow Sea Trough. Most of the sediment from the Changjiang River mouth is carried to the mud patch off the coast of the Zhejiang and Fujian provinces but with part of this sediment also transported to the Yellow Sea Trough. The model shows that it is difficult to transport land-derived sediment to the Okinawa Trough mud patch under normal conditions. The model also has difficulty accounting for the deposition of sediment in the region to the southwest of Cheju Island and offshore from the Zhejiang and Fujian provinces, an issue requiring further study.
Journal of Geophysical Research: Oceans, 2015
Hourly tide-gauge data along the coast of China are used to evaluate changes in extreme water lev... more Hourly tide-gauge data along the coast of China are used to evaluate changes in extreme water levels in the past several decades. Mean sea level, astronomical tide, nontidal component and the tidesurge interaction was analyzed separately to assess their roles in the changes of extreme sea levels. Mean sea level at five tide gauges, Kanmen, Keelung, Zhapo, Xiamen and Quarrybay, show significant increasing trends during the past decades (1954-2013) with a rate of about 1.4-3.5 mm/yr. At Keelung, Kaohsiung and Quarrybay the mean high waters increased during 1954-2013 with a rate from 0.6 to 1.8 mm/yr, while the annual mean tidal range rose at the same time by 0.9 to 3.8 mm/yr. In terms of storm surge intensities, there is interannual variability and decadal variability but five tide gauges show significant decreasing trends, and three gauges, at Keelung, Xiamen and Quarrybay, exhibited significant increases of extreme sea levels with trends of 1.5-6.0 mm/yr during 1954-2013. Significant tide-surge interactions were found at all 12 tide gauges, but no obvious change was found during the past few decades. The changes in extreme sea levels in this area are strongly related to the changes of mean sea levels (MSL). At gauges, where the tide-surge interaction is large, the astronomic tides are also an important factor for the extreme sea levels, whereas tide gauges with little tide-surge interaction, the changes of wind driven storm surge component adds to the change of the extreme sea levels. Key Points: Changes in extreme sea levels here are strongly related to the changes of mean sea levels The tide and surge are also important in the changes of extreme sea level Tide-surge interaction plays an important role, but not directly
Journal of Geophysical Research: Oceans
[1] A regional ocean circulation model (ROMS) is used to simulate the Chinese land-derived sedime... more [1] A regional ocean circulation model (ROMS) is used to simulate the Chinese land-derived sediment transport in the Bohai Sea, Yellow Sea, and East China Sea (BYECS). The model includes the effect of currents, tides, and waves on the sediment transport and is used to study the pathway and dynamic mechanisms of the fine-grain sediment transport from the Huanghe River (Yellow River), the Old Huanghe Delta, and the Changjiang River (Yangtze River) in the BYECS. The seasonal variability of the sediment transport in the BYECS and the sources of the Yellow Sea Trough mud patch, the mud patch southwest of Cheju Island, the mud patch offshore from the Zhejiang and Fujian provinces and the Okinawa Trough mud patch are discussed. The results show that the Huanghe River sediment can be transported to the Yellow Sea Trough, but little makes it to the outer shelf while the Old Huanghe Delta sediment is mainly transported to the Yellow Sea Trough. Most of the sediment from the Changjiang River m...
Journal of Ocean University of China, 2013
actions, transmission to the real economy of funding shocks to banks, and characteristics of rene... more actions, transmission to the real economy of funding shocks to banks, and characteristics of renegotiated debt contracts. Despite the range of the topics, all of the papers have an important feature in common. All their data samples cover the periods before, during, and after the financial crisis. Thus, the results obtained in these papers are useful to understand how banks may improve their strategies, and how future policy to enhance regulatory and supervisory effectiveness after the financial crisis may be driven. The special issue starts with the paper of Castro and Galan (2019, this issue), who analyze the drivers of total factor productivity (TFP) of Spanish banks from early 2000 until after the financial crisis. The Spanish banking sector is an interesting laboratory to carry out this type of analysis because, in 2012, Spain received European Union funds to recapitalize and restructure its financial sector. As a result, after the crisis, the Spanish banking sector underwent a significant restructuring, which included large numbers of bank mergers and a transformation of its savings banks into either social foundations or commercial banks. The key questions addressed by the paper are how the Spanish banking sector may sustain its level of productivity and whether there may still be room for further consolidation following a major restructuring process. To answer these questions the authors analyze the underlying reasons behind the changes in banks' productivity over time. Using a variable cost frontier approach the authors decompose changes in TFP into inefficiency changes and scale economies changes. Moreover, in the estimation of the cost frontier the paper takes into account equity capital and risk measures in order to avoid biases in the estimation of scale economies. One novelty of the paper is the approach proposed for measuring risk. The authors present a unified composite ex-ante risk measure that incorporates different types of risk regarding
Journal of Marine Systems
Measurement Science and Technology
Journal of Ocean University of China
Journal of Oceanology and Limnology
International Journal of Applied Earth Observation and Geoinformation
Journal of Geophysical Research: Oceans
Journal of Ocean University of China
Laser in situ scattering and transmissometry (LISST) significantly improves our ability to assess... more Laser in situ scattering and transmissometry (LISST) significantly improves our ability to assess particle size distribution (PSD) in seawater, while wide-ranging measurements of the organic-inorganic compositions of suspended particulate matters (SPM) are still difficult by using traditional methods such as microscopy. In this study, PSD properties and SPM compositions around the Bohai Strait (China) were investigated based on the measurements by LISST in combination with hydro-biological parameters collected from a field survey in summer 2014. Four typical PSD shapes were found in the region, namely right-peak, left-peak, double-peak and negative-skew shapes. The double-peak and negative-skew shapes may interconvert into each other along with strong hydrodynamic variation. In the upper layer of the Bohai Sea, organic particles were in the majority, with inorganic particles rarely observed. In the bottom layer, SPM were the mixture of organic and inorganic matters. LISST provided valuable baseline information on size-resolved organic-inorganic compositions of SPM: the size of organic particles mainly ranged from 4 to 20 µm and 40 to 100 µm, while most SPM ranging from 20 to 40 µm were composed of inorganic sediment.
Continental Shelf Research
Continental Shelf Research
Biogeosciences Discussions, 2016
In a stratified water column, the nitracline is a layer where the nitrate concentration increases... more In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not well established. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions for the system of phytoplankton and nutrient. The analytical solution shows that the nitracline depth is deeper than the depth of SCML, shoaling with an increase in light attenuation coefficient and...
Journal of Ocean University of China, 2016
Cont Shelf Res, 2008
Salinity is an important component of the marine system. Previous studies indicated that the mean... more Salinity is an important component of the marine system. Previous studies indicated that the mean salinity in the Bohai Sea had increased by 2.0psu in the second half of the 20th century, mainly due to a sharp decrease in the Yellow River runoff, and also the effects of large-scale climatic variations and the intrusions of the North Yellow Sea Water
International Journal of Applied Earth Observation and Geoinformation, Sep 1, 2010
Study of suspended particulate matter (SPM) transport in a coastal area, traditionally supported ... more Study of suspended particulate matter (SPM) transport in a coastal area, traditionally supported by field observation and numerical simulation, benefits now from numerous available remotely sensed ocean color images. Numerical simulation of SPM dynamics can be the supplement to remote sensing data which response the discrete states for different point-in-times. It would be helpful for monitoring coastal water environment in a real sense if remote sensing can be coupled with numerical simulation to get a promising water environmental dynamics in time and space domain. In this study, an approach coupling ocean color image retrieval with numerical simulation of SPM transport is proposed. Instead of traditionally specifying the spatial-constant SPM concentration as an initial condition of sediment transport models, the spatial-variant SPM concentration retrieved from MERIS image initializes the models. And the SPM resuspension and deposition can be interactively inspected and verified. Combining the simulated results with the remote sensing retrieved results, the parameters of hydrodynamic model and sediment transport model can be calibrated. The Bohai Sea in China is selected to test the approach. An optimized group of parameters are calibrated by using the SPM concentration retrieved from MERIS image in the Bohai Sea. Compared with the SPM initialization of spatial-constant, the spatial-variant SPM input retrieved results can quickly response to the changes of sediment concentration in real sense. The results show a well agreement with the in situ measurements. The results show that the approach is good at simulating SPM dynamics in clear waters with a SPM concentration lower than 20 mg/l and more effective in the area with less land source affected. The study suggests that the proposed approach is effective for monitoring coastal water environment roundly and three-dimensionally.
Journal of Geophysical Research: Oceans, 2013
A regional ocean circulation model (ROMS) is used to simulate the Chinese landderived sediment tr... more A regional ocean circulation model (ROMS) is used to simulate the Chinese landderived sediment transport in the Bohai Sea, Yellow Sea, and East China Sea (BYECS). The model includes the effect of currents, tides, and waves on the sediment transport and is used to study the pathway and dynamic mechanisms of the fine-grain sediment transport from the Huanghe River (Yellow River), the Old Huanghe Delta, and the Changjiang River (Yangtze River) in the BYECS. The seasonal variability of the sediment transport in the BYECS and the sources of the Yellow Sea Trough mud patch, the mud patch southwest of Cheju Island, the mud patch offshore from the Zhejiang and Fujian provinces and the Okinawa Trough mud patch are discussed. The results show that the Huanghe River sediment can be transported to the Yellow Sea Trough, but little makes it to the outer shelf while the Old Huanghe Delta sediment is mainly transported to the Yellow Sea Trough. Most of the sediment from the Changjiang River mouth is carried to the mud patch off the coast of the Zhejiang and Fujian provinces but with part of this sediment also transported to the Yellow Sea Trough. The model shows that it is difficult to transport land-derived sediment to the Okinawa Trough mud patch under normal conditions. The model also has difficulty accounting for the deposition of sediment in the region to the southwest of Cheju Island and offshore from the Zhejiang and Fujian provinces, an issue requiring further study.
Journal of Geophysical Research: Oceans, 2015
Hourly tide-gauge data along the coast of China are used to evaluate changes in extreme water lev... more Hourly tide-gauge data along the coast of China are used to evaluate changes in extreme water levels in the past several decades. Mean sea level, astronomical tide, nontidal component and the tidesurge interaction was analyzed separately to assess their roles in the changes of extreme sea levels. Mean sea level at five tide gauges, Kanmen, Keelung, Zhapo, Xiamen and Quarrybay, show significant increasing trends during the past decades (1954-2013) with a rate of about 1.4-3.5 mm/yr. At Keelung, Kaohsiung and Quarrybay the mean high waters increased during 1954-2013 with a rate from 0.6 to 1.8 mm/yr, while the annual mean tidal range rose at the same time by 0.9 to 3.8 mm/yr. In terms of storm surge intensities, there is interannual variability and decadal variability but five tide gauges show significant decreasing trends, and three gauges, at Keelung, Xiamen and Quarrybay, exhibited significant increases of extreme sea levels with trends of 1.5-6.0 mm/yr during 1954-2013. Significant tide-surge interactions were found at all 12 tide gauges, but no obvious change was found during the past few decades. The changes in extreme sea levels in this area are strongly related to the changes of mean sea levels (MSL). At gauges, where the tide-surge interaction is large, the astronomic tides are also an important factor for the extreme sea levels, whereas tide gauges with little tide-surge interaction, the changes of wind driven storm surge component adds to the change of the extreme sea levels. Key Points: Changes in extreme sea levels here are strongly related to the changes of mean sea levels The tide and surge are also important in the changes of extreme sea level Tide-surge interaction plays an important role, but not directly
Journal of Geophysical Research: Oceans
[1] A regional ocean circulation model (ROMS) is used to simulate the Chinese land-derived sedime... more [1] A regional ocean circulation model (ROMS) is used to simulate the Chinese land-derived sediment transport in the Bohai Sea, Yellow Sea, and East China Sea (BYECS). The model includes the effect of currents, tides, and waves on the sediment transport and is used to study the pathway and dynamic mechanisms of the fine-grain sediment transport from the Huanghe River (Yellow River), the Old Huanghe Delta, and the Changjiang River (Yangtze River) in the BYECS. The seasonal variability of the sediment transport in the BYECS and the sources of the Yellow Sea Trough mud patch, the mud patch southwest of Cheju Island, the mud patch offshore from the Zhejiang and Fujian provinces and the Okinawa Trough mud patch are discussed. The results show that the Huanghe River sediment can be transported to the Yellow Sea Trough, but little makes it to the outer shelf while the Old Huanghe Delta sediment is mainly transported to the Yellow Sea Trough. Most of the sediment from the Changjiang River m...
Journal of Ocean University of China, 2013
actions, transmission to the real economy of funding shocks to banks, and characteristics of rene... more actions, transmission to the real economy of funding shocks to banks, and characteristics of renegotiated debt contracts. Despite the range of the topics, all of the papers have an important feature in common. All their data samples cover the periods before, during, and after the financial crisis. Thus, the results obtained in these papers are useful to understand how banks may improve their strategies, and how future policy to enhance regulatory and supervisory effectiveness after the financial crisis may be driven. The special issue starts with the paper of Castro and Galan (2019, this issue), who analyze the drivers of total factor productivity (TFP) of Spanish banks from early 2000 until after the financial crisis. The Spanish banking sector is an interesting laboratory to carry out this type of analysis because, in 2012, Spain received European Union funds to recapitalize and restructure its financial sector. As a result, after the crisis, the Spanish banking sector underwent a significant restructuring, which included large numbers of bank mergers and a transformation of its savings banks into either social foundations or commercial banks. The key questions addressed by the paper are how the Spanish banking sector may sustain its level of productivity and whether there may still be room for further consolidation following a major restructuring process. To answer these questions the authors analyze the underlying reasons behind the changes in banks' productivity over time. Using a variable cost frontier approach the authors decompose changes in TFP into inefficiency changes and scale economies changes. Moreover, in the estimation of the cost frontier the paper takes into account equity capital and risk measures in order to avoid biases in the estimation of scale economies. One novelty of the paper is the approach proposed for measuring risk. The authors present a unified composite ex-ante risk measure that incorporates different types of risk regarding