Guimei Liu's research while affiliated with National Marine Environmental Forecasting Center and other places

Publications (22)

Article
Full-text available
Contrasting decrease and increase trends of sea surface temperature (SST) have been documented in the western Subarctic (WSA) and the rest of the Northwest Pacific (NWP) from 1958 to 2017, respectively. Consequently, more (less) total carbon dioxide (TCO2) due to ocean cooling (warming) is transported to the surface, which leads to increase (decrea...
Preprint
Full-text available
Several models for estuarine physical processes and biogeochemistry have been developed over last decades. One of the most comprehensive coupled model systems, Finite Volume Community Coastal Model (FVCOM) coupled with European Regional Seas Ecosystem Model (ERSEM) through the Framework for Aquatic Biogeochemical Models (FABM) has been implemented...
Article
Full-text available
Marginal seas play important roles in regulating the global carbon budget, but there are great uncertainties in estimating carbon sources and sinks in the continental margins. A Pacific basin-wide physical-biogeochemical model is used to estimate primary productivity and air-sea CO2 flux in the South China Sea (SCS), the East China Sea (ECS), and t...
Article
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An operational three-dimensional oil spill model is developed by the National Marine Environmental Forecasting Center (NMEFC), State Oceanic Administration, China, and the model has been running for 9 a. On June 4 and 17, 2011, oil is spilled into the sea water from two separate oil platforms in the Bohai Bay, i.e., Platforms B and C of Penglai 19-...
Article
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In the east of China’s seas, there is a wide range of the continental shelf. The nutrient cycle and the carbon cycle in the east of China’s seas exhibit a strong variability on seasonal to decadal time scales. On the basis of a regional ocean modeling system (ROMS), a three dimensional physical-biogeochemical model including the carbon cycle with t...
Article
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The effects of sea surface temperature (SST) data assimilation in two regional ocean modeling systems were examined for the Yellow Sea (YS). The SST data from the Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) were assimilated. The National Marine Environmental Forecasting Center (NMEFC) modeling system uses the ensemble optimal i...
Article
Full-text available
Based on a novel estimation of background-error covariances for assimilating Argo profiles, an oceanographic three-dimensional variational (3DVAR) data assimilation scheme was developed for the northwestern Pacific Ocean model (NwPM) for potential use in operational predictions and maritime safety applications. Temperature and salinity data extract...
Article
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The phenomenon of low dissolved oxygen (known as hypoxia) in a coastal ocean system is closely related to a combination of anthropogenic and natural factors. Marine hypoxia occurs in the Yangtze Estuary, China, with high frequency and long persistence. It is related primarily to organic and nutrient enrichment influenced by river discharges and phy...
Article
Full-text available
In this paper, the performance of two operational ocean forecasting systems, the global Mercator Océan (MO) Operational System, developed and maintained by Mercator Océan in France, and the regional South China Sea Operational Forecasting System (SCSOFS), by the National Marine Environmental Forecasting Center (NMEFC) in China, have been examined....
Article
Full-text available
The phenomenon of low dissolved oxygen (known as hypoxia) in coastal ocean system is closely related to a combination of anthropogenic and natural factors. Marine hypoxic occurs in the Yangtze Estuary, China with high frequency and long persistence. It’s known that it related primarily to organic and nutrient enrichment influenced by river discharg...
Article
Full-text available
Based on a novel specification of the background error covariance applying to Argos profiles assimilation, an oceanographic three-dimensional variational (3DVAR) data assimilation scheme is set up in the Regional Oceanic Model system (ROMs). Temperature and salinity data extracted from Argos profiles in 2006 have been assimilated into the North-Wes...
Article
Full-text available
In this paper, the performances of two operational ocean forecasting systems, Mercator Océan (MO) in France and South China Sea Operational Forecasting System (SCSOFS) in China, have been examined. Both systems can provide science-based nowcast/forecast products, such as temperature, salinity, water level and ocean circulations. Based on the observ...
Article
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In order to develop a coupled basin scale model of ocean circulation and biogeochemical cycling, we present a biogeochemical model including 12 components to study the ecosystem in the China coastal seas (CCS). The formulation of phytoplankton mortality and zooplankton growth are modified according to biological characteristics of CCS.The four sens...
Article
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The prediction of sea surface temperature (SST) is an essential task for an operational ocean circulation model. A sea surface heat flux, an initial temperature field, and boundary conditions directly affect the accuracy of a SST simulation. Here two quick and convenient data assimilation methods are employed to improve the SST simulation in the do...
Article
Full-text available
Three dimensional oceanic circulations in the North Pacific Ocean are simulated using the Regional Ocean Model System (ROMS). The model very well reproduces the main oceanic circulation patterns and the hydrodynamic structures in the North Pacific Ocean, especially in the China Seas. Eight transects around the China Seas are selected to analyze vol...
Article
The Yellow Sea is located between the China Mainland and the Korean Peninsula, representing a typical shallow epicontinental sea. The Yellow Sea Cold Water Mass (YSCWM) is one of the most important physical features in the Yellow Sea. The characteristics of vertical profiles and seasonal variations of biogenic elements in the YSCWM may lead the var...
Article
The ensemble optimal interpolation (EnOI) is applied to the regional ocean modeling system (ROMS) with the ability to assimilate the along-track sea level anomaly (TSLA). This system is tested with an eddy-resolving system of the South China Sea (SCS). Background errors are derived from a running seasonal ensemble to account for the seasonal variab...
Article
Relative roles of Ekman transport and Ekman pumping in driving summer upwelling in the South China Sea (SCS) are examined using QuikSCAT scatterometer wind data. The major upwelling regions in the SCS are the coastal regions east and southeast of Vietnam (UESEV), east and southeast of Hainan Island (UESEH), and southeast of Guangdong province (USEG...
Article
To understand the response of marine ecosystem to environmental factors, the oceanographic (physical and biochemical) data are analyzed to examine the spatio-temporal distributions of chlorophyll a (Chl a) associatedwith surface temperature, winds and height anomaly for long periods (1997–2008) in the western South China Sea (SCS). The results indi...
Article
Full-text available
On March 11, 2011, a large earthquake and subsequent tsunami near the east coast of Japan destroyed the Fukushima Daiichi nuclear power plant (FD-NPP), causing a massive release of nuclear contaminants. In this paper, a Pacific basin-wide physical dispersion model is developed and used to investigate the transport of nuclear contaminants. The Pacif...
Article
The response of chlorophyll a (Chl a) concentration to wind stress is analyzed in the South China Sea (SCS), using in-situ data of Chl a and remote sensing data (QuikScat-sea surface wind (SSW), AVHRR-sea surface temperature (SST), AVISO merged-sea level anomalies (SLA), SeaWiFS-derived Chl a and MODIS Terra-derived Chl a) in August/September/Octob...
Article
Mesoscale eddy activity and its modulation mechanism in the South China Sea (SCS) are investigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy (EKE) level of basin-wide averages show a distinct seasonal cycle with the maximum in August–December and the minimum in February–May. Furthermore,...

Citations

... Ship-borne measurements of atmospheric CO 2 and CH 4 are also conducted in different seas/oceans (Zang et al., 2013;Zhang et al., 2017). To date, many coastal areas, which are important sources for climatically active trace gases, are still greatly undersampled for GHGs (Cai et al., 2006;Kong et al., 2010;Ji et al., 2017). There have been many studies on the changes in atmospheric CO 2 and CH 4 in urban and suburban China (e.g., Mt. ...
... The weathering model accounts for spreading, evaporation and emulsification. The details of the NMEFC oil model framework can be found in Zhang et al. [16] and later Li et al. [17] and Yang et al. [18]. The products are spill trajectory, geographical distribution, beaching behaviour, oil weathering property and oil mass balance. ...
... Open boundary conditions are derived by employing downscaling technology: from global to NWP, from NWP to ECS and SCS, and from ECS to BS, and are also complemented by harmonic constants of major tidal constituents extracted from the Oregon State University Tidal Inversion [http ://volkov.oce.orst.edu/tides/]. A 3DVar data assimilation scheme or an EnOI scheme was implemented to assimilate sea level anomaly , satellite sea surface temperature , Argo temperature and salinity profiles [35][36][37]. These ocean circulation systems are running fully operationally at NMEFC, providing three-dimensional forecasting productsof sea water temperature, salinity, and currents to drive the oil spill models. ...
... The open boundary conditions, i.e., hourly water temperature, salinity, current velocities, and sea level in 2005 were provided by the National Marine Environmental Forecasting Center (NMEFC). The open boundary data are interpolated from the results of a large region model from the NMEFC (Ji et al., 2017a(Ji et al., , 2017b. ...
... Open boundary conditions are derived by employing downscaling technology: from global to NWP, from NWP to ECS and SCS, and from ECS to BS, and are also complemented by harmonic constants of major tidal constituents extracted from the Oregon State University Tidal Inversion [http ://volkov.oce.orst.edu/tides/]. A 3DVar data assimilation scheme or an EnOI scheme was implemented to assimilate sea level anomaly , satellite sea surface temperature , Argo temperature and salinity profiles [35][36][37]. These ocean circulation systems are running fully operationally at NMEFC, providing three-dimensional forecasting productsof sea water temperature, salinity, and currents to drive the oil spill models. ...
... The formation and variations of ECS hypoxia are influenced by multiple factors. On the one hand, the annual variations in hypoxia mainly depend on variations in stratification, which forms through the overlapping of freshwater above saline water (Chi et al., 2020;Luo et al., 2018;Qian et al., 2017;Wang et al., 2012;Wei et al., 2007Wei et al., , 2015Zhang et al., 2019;Zheng et al., 2016;Zhou et al., 2010). On the other hand, chemical oxidation, such as OM decomposition, plays a significant role in fueling DO consumption in the stratified water column (Chi et al., 2017;Li et al., 2002;Wang et al., 2016b;Wei et al., 2017;Zhu et al., 2011). ...
... This model consists of a fine-resolution (2 km) coastal model around Japan and an eddy-resolving (10 km) northwestern Pacific model with one-way nesting. The Chinese Global operational Oceanography Forecasting System was developed and operated based on the Regional Ocean Modelling System (ROMS, Shchepetkin and McWilliams, 2005) and NEMO by the National Marine Environmental Forecasting Center, covering six subdomains from global to polar regions, the Indian Ocean, the northwestern Pacific, the Yellow Sea and the East China Sea (Kourafalou et al., 2015), and the SCS (Zhu et al., 2016), with horizontal resolutions ranging from 1/12 to 1/30 • . It should be noted that there are considerable differences among these systems in many aspects, such as the model codes, area coverage, horizontal and vertical resolutions, and data assimilation schemes, which are based on the user needs and regional ocean characteristics. ...
... Currently, it is generally accepted that water column stratification and organic matter (OM) decomposition are two essential factors for hypoxia formation off the CE and its adjacent waters J.R. Zhu et al., 2016;Wang et al., 2017). In addition, the formation of hypoxia is closely related to the Changjiang River plume (Zheng et al., 2016;W.X. Zhang et al., 2018;Wei et al., 2020), Kuroshio intrusion (Qian et al., 2017;Zhou et al., 2017;Luo et al., 2018), wind mixing (Ni et al., 2016;Zheng et al., 2016;Wang et al., 2017), and submarine groundwater (Guo et al., 2020). ...
... Firstly, we used a sensitivity formulation to perform a screening sensitivity analysis. The following sensitivity function is employed to measure the local sensitivity of the biological parameters to model outputs [45,48]: ...
... SST is also a good predictor in a hydrostatic ocean general circulation model, hence SST bias is one of the main elements for evaluation of numerical modeling skills. Many factors contribute in the SST simulation error, including the constraint of the physical model, the quality of the surface atmosphere, the uncertainty of the initial field, the open boundary, and subsurface mixing (Qiao et al., 2004;Ji et al., 2015;Sun et al., 2020). ...