scholarly journals Satellite Retrieval of Surface Water Nutrients in the Coastal Regions of the East China Sea

2018 ◽  
Vol 10 (12) ◽  
pp. 1896 ◽  
Author(s):  
Difeng Wang ◽  
Qiyuan Cui ◽  
Fang Gong ◽  
Lifang Wang ◽  
Xianqiang He ◽  
...  
Keyword(s):  
Remote Sensing ◽  
East China Sea ◽  
Spatiotemporal Variability ◽  
East China ◽  
Changjiang River ◽  
The East China Sea ◽  
Coastal Regions ◽  
China Sea ◽  
Satellite Retrieval ◽  
Proposed Model

Due to the tremendous flux of terrestrial nutrients from the Changjiang River, the waters in the coastal regions of the East China Sea (ECS) are exposed to heavy eutrophication. Satellite remote sensing was proven to be an ideal way of monitoring the spatiotemporal variability of these nutrients. In this study, satellite retrieval models for nitrate and phosphate concentrations in the coastal regions of the ECS are proposed using the back-propagation neural network (BP-NN). Both the satellite-retrieved sea surface salinity (SSS) and remote-sensing reflectance (Rrs) were used as inputs in our model. Compared with models that only use Rrs or SSS, the newly proposed model performs much better in the study area, with determination coefficients (R2) of 0.98 and 0.83, and mean relative error (MRE) values of 18.2% and 17.2% for nitrate and phosphate concentrations, respectively. Based on the proposed model and satellite-retrieved Rrs and SSS datasets, monthly time-series maps of nitrate and phosphate concentrations in the coastal regions of the ECS for 2015–2017 were retrieved for the first time. The results show that the distribution of nutrients had a significant seasonal variation. Phosphate concentrations in the ECS were lower in spring and summer than those in autumn and winter, which was mainly due to phytoplankton uptake and utilization. However, nitrate still spread far out into the ocean in summer because the diluted Changjiang River water remained rich in nitrogen.

scholarly journals The large variation in organic carbon consumption in spring in the East China Sea

2013 ◽  
Vol 10 (5) ◽  
pp. 2931-2943 ◽  
Author(s):  
C.-C. Chen ◽  
G.-C. Gong ◽  
F.-K. Shiah ◽  
W.-C. Chou ◽  
C.-C. Hung
Keyword(s):  
Low Temperature ◽  
Organic Carbon ◽  
East China Sea ◽  
Phytoplankton Growth ◽  
East China ◽  
Changjiang River ◽  
Carbon Consumption ◽  
The East China Sea ◽  
China Sea ◽  
The Changjiang River

Abstract. A tremendous amount of organic carbon respired by plankton communities has been found in summer in the East China Sea (ECS), and this rate has been significantly correlated with fluvial discharge from the Changjiang River. However, respiration data has rarely been collected in other seasons. To evaluate and reveal the potential controlling mechanism of organic carbon consumption in spring in the ECS, two cruises covering almost the entire ECS shelf were conducted in the spring of 2009 and 2010. These results showed that although the fluvial discharge rates were comparable to the high riverine flow in summer, the plankton community respiration (CR) varied widely between the two springs. In 2009, the level of CR was double that of 2010, with mean (± SD) values of 111.7 (±76.3) and 50.7 (±62.9) mg C m−3 d−1, respectively. The CR was positively correlated with concentrations of particulate organic carbon and/or chlorophyll a (Chl a) in 2009 (all p < 0.01). These results suggest that the high CR rate in 2009 can be attributed to high planktonic biomasses. During this period, phytoplankton growth flourished due to allochthonous nutrients discharged from the Changjiang River. Furthermore, higher phytoplankton growth led to the absorption of an enormous amount of fugacity of CO2 (fCO2) in the surface waters, even with a significant amount of inorganic carbon regenerated via CR. In 2010, even more riverine runoff nutrients were measured in the ECS than in 2009. Surprisingly, the growth of phytoplankton in 2010 was not stimulated by enriched nutrients, and its growth was likely limited by low water temperature and/or low light intensity. Low temperature might also suppress planktonic metabolism, which could explain why the CR was lower in 2010. During this period, lower surface water fCO2 may have been driven mainly by physical process(es). To conclude, these results indicate that high organic carbon consumption (i.e. CR) in the spring of 2009 could be attributed to high planktonic biomasses, and the lower CR rate during the cold spring of 2010 might be likely limited by low temperature in the ECS. This further suggests that the high inter-annual variability of organic carbon consumption needs to be kept in mind when budgeting the annual carbon balance.

scholarly journals REMOTE SENSING OF AEROSOL OPTICAL THICKNESS ON THE EAST CHINA SEA

2001 ◽  
Vol 9 ◽  
pp. 175-180
Author(s):  
Shuichi HASEGAWA ◽  
Sachio OHTA ◽  
Naoto MURAO ◽  
Sadamu YAMAGATA
Keyword(s):  
Remote Sensing ◽  
East China Sea ◽  
Optical Thickness ◽  
Aerosol Optical Thickness ◽  
East China ◽  
The East China Sea ◽  
China Sea

scholarly journals The large variation in organic carbon consumption in spring in the East China Sea

2012 ◽  
Vol 9 (11) ◽  
pp. 16533-16564
Author(s):  
C.-C. Chen ◽  
G.-C. Gong ◽  
F.-K. Shiah ◽  
W.-C. Chou ◽  
C.-C. Hung
Keyword(s):  
Organic Carbon ◽  
East China Sea ◽  
Phytoplankton Growth ◽  
East China ◽  
Community Respiration ◽  
Changjiang River ◽  
Carbon Consumption ◽  
The East China Sea ◽  
China Sea ◽  
The Changjiang River

Abstract. A tremendous amount of organic carbon respired by planktonic communities has been found in summer in the East China Sea (ECS), and this rate has been significantly correlated with fluvial discharge from the Changjiang River. However, data related to this issue in other seasons have rarely been collected. To evaluate and reveal the potential controlling mechanism of organic carbon consumption in spring in the ECS, research using stations covering almost the entire ECS shelf was conducted in the spring of 2009 and 2010. During both periods, the fluvial discharges were similar, and these rates were comparable to high riverine flow in summer. Interestingly, planktonic community respiration (CR) varied widely in both springs; in 2009, the level of CR was double that of 2010, with mean (± SD) values of 111.7 (± 76.3) and 50.7 (± 62.9) mg C m−3 d−1, respectively. The CR was positively linearly regressed with concentrations of particulate organic carbon and/or chlorophyll a (Chl a) in 2009 (all p< 0.01). These results suggest that the rate was dependent on planktonic activities, especially that of phytoplankton, in 2009. During this period, phytoplankton growth flourished due to allochthonous nutrients discharged from the Changjiang River. Furthermore, higher phytoplankton growth leaded to the absorption of an enormous amount of fugacity of CO2 (fCO2) in the surface waters, even with a significant amount of inorganic carbon regenerated via CR. In 2010, there were even more riverine runoff nutrients into the ECS than in 2009. Surprisingly, the growth of phytoplankton in 2010 was not stimulated by enriched nutrients, and its growth was likely limited by low water temperature and/or low light intensity. Low temperature might also suppress planktonic metabolism, and this could explain why the CR was lower in 2010. During this period, lower surface water fCO2 might have mainly been driven by physical process(es). To conclude, these results indicate that organic carbon consumption (i.e. CR) in the ECS in spring might be controlled by the magnitude of planktonic activities and physical factor (e.g. temperature), and that the latter is especially important during a cold spring season. This further suggests that the high intraseasonal variability of organic carbon consumption needs to be kept in mind when budgeting the annual carbon balance.

scholarly journals Estimating dissolved organic carbon inventories in the East China Sea using remote-sensing data

2014 ◽  
Vol 119 (10) ◽  
pp. 6557-6574 ◽  
Author(s):  
Qiong Liu ◽  
Delu Pan ◽  
Yan Bai ◽  
Kai Wu ◽  
Chen-Tung Authur Chen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
East China Sea ◽  
Remote Sensing Data ◽  
East China ◽  
The East China Sea ◽  
Sensing Data ◽  
China Sea

Influence of the Changjiang River Flood on Synechococcus Ecology in the Surface Waters of the East China Sea

2013 ◽  
Vol 67 (2) ◽  
pp. 273-285 ◽  
Author(s):  
Chih-Ching Chung ◽  
Chin-Yi Huang ◽  
Gwo-Ching Gong ◽  
Yun-Chi Lin
Keyword(s):  
East China Sea ◽  
Surface Waters ◽  
East China ◽  
Changjiang River ◽  
The East China Sea ◽  
China Sea ◽  
The Changjiang River ◽  
River Flood

A regional remote sensing algorithm for total suspended matter in the East China Sea

2012 ◽  
Vol 124 ◽  
pp. 819-831 ◽  
Author(s):  
Zhihua Mao ◽  
Jianyu Chen ◽  
Delu Pan ◽  
Bangyi Tao ◽  
Qiankun Zhu
Keyword(s):  
Remote Sensing ◽  
East China Sea ◽  
Suspended Matter ◽  
Total Suspended Matter ◽  
East China ◽  
The East China Sea ◽  
China Sea ◽  
Remote Sensing Algorithm
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