scholarly journals Adjoint Assimilation of SeaWiFS data into a Marine Ecosystem Dynamical Model of the Bohai Sea and the North Yellow Sea

2012 ◽  
Vol 13 ◽  
pp. 2045-2061 ◽  
Author(s):  
C.H. Wang ◽  
X.Y. Li ◽  
X.Q. Lv
Keyword(s):  
Yellow Sea ◽  
Bohai Sea ◽  
Marine Ecosystem ◽  
Dynamical Model ◽  
North Yellow Sea ◽  
The Bohai Sea ◽  
The North ◽  
Adjoint Assimilation

Data assimilation in a coupled physical-biological model for the Bohai Sea and the Northern Yellow Sea

2008 ◽  
Vol 59 (6) ◽  
pp. 529 ◽  
Author(s):  
Qing Xu ◽  
Hui Lin ◽  
Yuguang Liu ◽  
Xianqing Lv ◽  
Yongcun Cheng
Keyword(s):  
Chlorophyll A ◽  
Annual Cycle ◽  
Yellow Sea ◽  
Bohai Sea ◽  
Biological Model ◽  
Model Parameters ◽  
The Bohai Sea ◽  
Northern Yellow Sea ◽  
Ocean Models ◽  
Adjoint Assimilation

One difficulty with coupled physical-biological ocean models is determining optimal values of poorly known model parameters. The variational adjoint assimilation method is a powerful tool for the automatic estimation of parameters. We used this method to incorporate remote-sensed chlorophyll-a data into a coupled physical-biological model developed for the Bohai Sea and the Northern Yellow Sea. A 3-D NPZD model of nutrients (N), phytoplankton (P), zooplankton (Z) and detritus (D) was coupled with a physical model, the Princeton Ocean Model. Sensitivity analysis was carried out to choose suitable control variables from the model parameters. Numerical twin experiments were then conducted to demonstrate whether the spatio-temporal resolutions of the observations were adequate for estimating values of the control variables. Finally, based on the success of the twin experiments, we included remote-sensed chlorophyll-a data in the NPZD model. With the adjoint assimilation of these chlorophyll-a data, the coupled model better describes spring and autumn phytoplankton blooms and the annual cycle of phytoplankton at the surface layer for the study area. The annual cycle of simulated surface nutrient concentrations also agreed well with field observations. The adjoint method greatly improves the modelling capability of coupled ocean models, helping us to better understand and model marine ecosystems.

scholarly journals Illicit drugs and their metabolites in 36 rivers that drain into the Bohai Sea and north Yellow Sea, north China

2016 ◽  
Vol 23 (16) ◽  
pp. 16495-16503 ◽  
Author(s):  
De-Gao Wang ◽  
Qiu-Da Zheng ◽  
Xiao-Ping Wang ◽  
Juan Du ◽  
Chong-Guo Tian ◽  
...  
Keyword(s):  
Yellow Sea ◽  
Illicit Drugs ◽  
North China ◽  
Bohai Sea ◽  
North Yellow Sea ◽  
The Bohai Sea

Numerical Study on Initial Field of Chemical Oxygen Demand with Adjoint Method

2013 ◽  
Vol 321-324 ◽  
pp. 252-258
Author(s):  
Chun Hui Wang ◽  
You Li Shen ◽  
Xian Qing Lv
Keyword(s):  
Chemical Oxygen Demand ◽  
Bohai Sea ◽  
Adjoint Method ◽  
Numerical Study ◽  
Marine Ecosystem ◽  
Oxygen Demand ◽  
Dynamical Model ◽  
Three Dimension ◽  
Initial Field ◽  
The Bohai Sea

Based on the simulation of a marine ecosystem dynamical model in the Bohai Sea, pseudo observations are assimilated to study the initial field of chemical oxygen demand (COD) by using the adjoint method. The three-dimension Princeton Ocean Model (POM) is used to calculate the ambient physical velocities, and only four tidal components (M2, S2, K1 and O1) are taken into account. First a prescribed initial distribution of COD is given. Run the forward model and we can pickup some pseudo observations. Then a set of twin experiments were designed to validate the inversion capability of this ecosystem dynamical model. It was discovered that no matter which form the initial field was, the adjoint method could reduce the misfit between inversion results and observations significantly, indicating that this model was stable and reliable. Therefore, this model could be applied in real experiment to simulate the initial field of COD in the Bohai Sea in future.

scholarly journals Subsurface low pH and carbonate saturation state of aragonite on China side of the North Yellow Sea: combined effects of global atmospheric CO<sub>2</sub> increase, regional environmental changes, and local biogeochemical processes

2013 ◽  
Vol 10 (2) ◽  
pp. 3079-3120 ◽  
Author(s):  
W.-D. Zhai ◽  
N. Zheng ◽  
C. Huo ◽  
Y. Xu ◽  
H.-D. Zhao ◽  
...  
Keyword(s):  
Yellow Sea ◽  
Bottom Water ◽  
Bohai Sea ◽  
Environmental Changes ◽  
Water Mass ◽  
Salinity Range ◽  
Saturation State ◽  
North Yellow Sea ◽  
The North ◽  
Subsurface Waters

Abstract. Based upon seven field surveys conducted between May 2011 and January 2012, we investigated pH, carbonate saturation state of aragonite (Ωarag), and ancillary parameters on the Chinese side of the North Yellow Sea, a western North Pacific continental margin of major economic importance. Subsurface waters were nearly in equilibrium with air in May and June. From July to October, the fugacity of CO2 (fCO2) of bottom water gradually increased to 697 ± 103 μatm and pH decreased to 7.83 ± 0.07 due to respiration/remineralization processes of primary production induced biogenic particles. In November and January, bottom water fCO2 decreased and pH gradually returned to an air-equilibrated level due to cooling enhanced vertical mixing. The corresponding bottom water Ωarag was 1.74 ± 0.17 (May), 1.77 ± 0.26 (June), 1.70 ± 0.26 (July), 1.72 ± 0.33 (August), 1.32 ± 0.31 (October), 1.50 ± 0.28 (November), and 1.41 ± 0.12 (January). Critically low Ωarag values of 1.0 to 1.2 were mainly observed in subsurface waters in a salinity range of 31.5–32.5 psu in October and November, accounting for ~ 10% of the North Yellow Sea area. Water mass derived from the adjacent Bohai Sea had a typical water salinity of 30.5–31.5 psu, and bottom water Ωarag values ranged mostly between 1.6 and 2.4. This study showed that the carbonate system in the North Yellow Sea was substantially influenced by global atmospheric CO2 increase. The community respiration/remineralization rates in typical North Yellow Sea bottom water mass were estimated at 0.55–1.0 μmol O2 kg−1 d−1 in warm seasons, leading to seasonal drops in subsurface pH and Ωarag. Outflow of the Bohai Sea water mass counteracted the subsurface Ωarag reduction in the North Yellow Sea.

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