Marine Ecosystem Dynamics Modeling Laboratory

Research

FVCOM

An unstructured grid, finite-volume, primitive equation community ocean model. FVCOM is coded for both Cartesian and spherical coordinates and can be easily applied tocoastal/estuarine applications as well as the global ocean. The updated version of FVCOM includes many new components such as a mass conservative wet/dry point treatment technique for simulating flooding/drying process, an interface to the general ocean turbulence model (GOTM) to provide multiple options for vertical mixing parameterization, a generalized lower trophic level food web biological module that allows users to build the own biological model, a 3-D sediment module based on the Community Sediment Transport model featuring suspended sediment and bedload transport, layered bed dynamics, flux-limit solution of sediment settling, unlimited number of sediment classes and bed layers and cohesive sediment erosion/deposition algorithms, a state of the art ice model based on CICE, a Lagrangian-based individual based model (IBM), as as other new improvements. FVCOM also incorporates advanced reduced and ensemble Kalman filters suitable for the forecast and hindcast application and adaptive optimal design of field sampling.

Gulf of Maine/Georges Bank

The Gulf of Maine (GoM)/Georges Bank (GB) is one of the most highly productive regions in the world. Our research in this region started in 1989, and focused on the physical-biological interaction on Georges Bank. Initially we used ECOM-si ( a version of POM) to examine the impacts of physical processes on the plankton dynamics in 1992. In our research, we found that the structured grid approach of ECOM-si/POM limited the capability of the model to resolve flow features in regions of steep and complex bathymetry. In response to this finding, we developed FVCOM, an unstructured grid model. At present, FVCOM has been demonstrated to be an advanced model that is capable of resolving the tidal resonance in the GoM, strong clockwise clockwise circulation over GB, frontal dynamics, eddy shedding, low-salinity plume, and other processes important to the complex Gulf circulation. Our resarach is funded through the NSF/NOAA Georges Bank/GLOBEC Program and the NOAA-SMAST fishery programs. The research is conducted in collaboration with the Woods Hole Oceanographic Institution, Scripps Institution of Oceanography, MIT, as well as other institutions.

Satilla River

The Satilla River Estuary is located on the Georgia coast. This is a typical tidal-dominated estuary characterized by an intensive array of intertidal salt marshes, tidal creeks, barriers, and islands, etc. We have developed a management model system for this estuary which is currently used operationally by the Georgia Sea Grant College Program and Georrgia Division of Natural Resource. The system is well validated using field measurement data, and hindcast model results are provided at this web for the purpose of both research and management.

Nantucket Sound

Nantucket Sound (NS) is a typical flow-through dynamical system bounded by Cape Cod (CC) and Nantucket Islands (NI) to the east, Vineyard Sound (VS), Woods Hole (WH), and Martha’s Vineyard (MV) to the west, and MV and VS to the south. A high resolution (20 to 500 m) FVCOM model has been developed for this coastal region with connection to Waquoit Bay (WB). This model system is being used to study the impact of physical variability on the NS ecosystem with the focus on the roles of flushing efficiencies between WB and NS. Development and validation of the NS model system is being carried out in collaboration with scientists at WHOI.

Mass Bay

Massachusetts Bay is characterized by complex irregular coastlines, harbors, and inlets. Stellwagen Bank, a shallow submarine bank, is located on the eastern open side of the bay. In order to capture the circulation and ecosystem in Mass Bay, a model is required that is capable of resolving the complex coastal geometry as well as the bathymetry of Stellwagan Bank. The unstructured grid, high resolution FVCOM has proven to be highly capable for the purpose of ecosystem management in the Bay.

Narragansett Bay/Mount Hope Bay

Narragansett Bay (NB) and Mt. Hope Bay (MHB) are located at the northeastern coast of the Atlantic Ocean with connection to both Massachusetts and Rhode Island. This is a typical integrated shallow water bay system that is driven by tides, winds and river discharge. Due to recent warming trends, the water temperature in NB and MHB increased by 1.0 degree C in the last 10 years, which has directly resulted in the intentisification of the water stratification in spring and summer. Hypoxia events have become more commonplace in the upper reaches of NB due to the increase of stratification and anthropogenic nutrient loading. A high resolution FVCOM model has been developed to examine the impact of both natural and human-derived environmental changes on the ecosystem in NB/MHB.

South Atlantic Bight

The South Atlantic Bight (SAB) refers to the continental shelf bounded in the north by 35 degree N, Cape Hatteras, North Carolina and to the south at 27 degree N, West Palm Peach, Florida. It is a typical concave shelf with a width of around 5 km off Palm Beach, 120 km off Georgia and South Carolina, and 30 km off Cape Hatteras.  According to physical processes that control the water properties, the SAB can be divided into 3 oceanographically climatologic zones: inner, middle, and outer shelves. The inner shelf, extending to the 20-m isobath, is characterized mainly by a low-salinity front, which results from the interaction between freshwater discharge, tidal mixing, and wind forcing. The outer shelf is dominated by by the shelf break front between the Gulf Stream and coastal waters. The mid-shelf, located in between the 20- and 40-m isobaths, is a region controlled by the combined processes of the inner and outer shelves. Our modeling efforts in this region started in 1994 with ECOM-si (a modified version of POM), and then shifted to FVCOM in 2001. Our previous ECOM-si experiments were focused on process-oriented studies of the low-salinity front and cross-frontal water exchange with understanding that ECOM-si is not suitable to the realistic application because of inability to resolve the complex coastal geometry and estuaries. In our modeling work of the SAB, FVCOM has replaced ECOM-si due to its extended capability in this region.

Louisiana-Texas Shelf

Field measurements were made to examine the near-inertical oscillation over the Louisiana-Texas Shelf (LATEX). A simple coupled biological and physical model (NPZ) was used to examine the impacts of river discharge on biological variability in this region. The global-scale Atlantic FVCOM is being developed, which will cover the Gulf of Mexico and Mississippi Rivers.

Cook Inlet/Alaska

The Cook Inlet/Alaska is characterizied by a near resonant tidal motion. Dr. Andy Proshutinsky, senior scientist at WHOI, has applied FVCOM to simulate tides in this region. The modeling experiments were made with technical assistance by the staff at MEDML. Examples for resonance tides are posted at this website.

Ogeechee River/Georgia

The Ogeechee River Estuary is fed by one of coastal Georgia’s five major river systems and is characterized by a series of barrier island complexes, tidal creeks, and extensive salt marshes. Two major black-water tributaries originating upstream in the piedmont, the Little Ogeechee River to the north and the Ogeechee River to the south, bring fresh water to the system. The estuary is a typical tidal-dominated dynamic system that is influenced significantly by upstream freshwater discharge. FVCOM was applied to this river to simulate the complex flooding/draining process over the estuarine-tidal creek-intertidal salt marsh complex. This is a good example of the application of FVCOM for the multiple river interaction system.

Altamaha River

The Altamaha River is one of the largest rivers terminating at the Georgia coast. Similar to Ogeechee River, it is a typical tidal-dominated estuary characterized with intensive intertidal salt marshes, tidal creeks, barriers, and islands, etc. We have configured FVCOM to resolve the circulation in this river. All technical difficulities have been well addressed. We are searching for funds to support the personnel for the modeling effort. Setting up a management-oriented model system for this river is critically important for the State of Georgia given the importance of this freshwater resource.

Okatee/Colletion River/South Carolina

The Okatee/Colleton River, South Carolina, is a study site of NOA-funded Land Use-Coastal Ecosystem Study (LU-CES) Program. The goal of the LUCES Program is to “develop scientifically sound predictive decision-making models (tools) that integrate changes in land use patterns with effects on hydrodynamics, transport processes and ecosystem function to assist in planning for sustainable coastal land use and resource management [Kleppel and Devoe (1999)].” How is the variability of DO in the tidal creek related to tidal dynamics and water exchange over the estuarine-intertidal salt marshes? This represents an application of a high resolution creek model configured with realistic high-resolution remotely-sensed bathymetry!

Changjiang River/East China Sea

Are you aware of the serious environmental issues in the Changjiang Estuary/East China Sea? Red tides frequently occur in this region. Is it due to nutrification or other reasons? What types of the model are suitable for this region? See our FVCOM application to the Changjiang River Estuary here.

Deep Bay/South China Sea

Deep Bay is located near Hong Kong, in the South China Sea. It is characterized by a narrow navigation channel, and large intertidal flooded zones. We performed a demo experiment to demonstrate the ability of FVCOM to resolve the circulation in this region.

Lake Superior

Why did previous models fail to simulate the Keweenaw Current, a strong jet current and thermal front along the Keweennaw Peninsula in Lake Superior? Why do we need to use FVCOM to replace the finite-difference modesl for this Lake? Why did our previous modeling experiments fail to resolve the current separation and eddy formation along the thermal front in Lake Superior? A new configuration of FVCOM has been set up for Lake Superior to examine its ability to resolve the current separation .

Lake Michigan

A coupled hydrodynamic and biological modeling experiment was carried out to examine how the sediment suspension could influence the ecosystem in Lake Michigan. The objective of this modeling study is to address the primary hypothesis that the effects of episodic meteorological events on biological productivity and chemical transformation are mainly through the modification of (1) the cross-margin and vertical transports of momentum, solutes, particulates, and organisms, (2) turbulent mixing, and (3) light limitation. Process-oriented modeling experiments posted at this website would give you some insight into the ecosystem dynamics in this lake.

East China Sea (Regional Ocean)

The East China/Yellow/Bohai Seas (ECYBS) are located on the western Pacific Ocean, with connection to the Japan/East Sea through the Korea/ Tsushima Strait to the northeast and the South China Sea through the Taiwan Strait to southwest. The East China Sea (ECS) covers the area originating around the Taiwan Strait at about 25 degree N, extending northeastward to the Kyushu islands, Japan and the Korea/Tsushima Strait, and bounding by the Ryukyu island chains on the southeastern open ocean.A line running northeastward from the mouth of the Changjiang to the southwestern tip of Korea is defined as the boundary between the Yellow Sea (YS) to the north and the ECS to the south.

We have applied ECOM-si to simulate tide-, wind- and buoyancy-driven circulation in this region. Recently, FVCOM is configured to replace ECOM-si. The flexibility of unstructued grids used in FVCOM makes the model capable to resolve the eddy formation due to Kuroshio, and near-coastal circulation.

Bohai Sea

The Bohai Sea (BS) is the semi-enclosed shallow basin with connection to the YS through the Bohai Strait. The water depth in the BS is about 20 m. This is the first test area used to validate FVCOM by comparison with ECOM-si and POM.

Jiaozhou Bay/East China Sea

Jiaozhou Bay, located on the western coast of the Yellow Sea (YS), P. R. China (N35o38′-36o18′, E120o04′-120 o23′), is a shallow semi-closed bay with a total area of about 400 km2 and an average water depth of 7 m. The biology of Jiaozhou Bay has changed dramatically in the last three decades due to the proliferation of industry, aquaculture, agriculture, and domestic sewage around or inside the bay. Annually averaged concentrations of total inorganic nitrogen and phosphate have increased from 1.2 and 0. 14 (mol /1 in 1962-63 to 10.4 and 0.45 (mol /l in 1992, respectively. The atomic ratio of total inorganic nitrogen to phosphate was about 10 in 1962-63, but has increased to 24.2. Nitrogen was previously a requisite component for the growth of phytoplankton in Jiaozhou Bay, but now the bay has turned into a phosphorous-limited ecosystem. See this website for some of our previous coupled biological and physical modeling experiments.

South China Sea (Regional Ocean)

The South China Sea is an interesting dynamical region characterized by strong tidal waves and internal solitons. A high-resolution South China Sea FVCOM was developed for this region. The link above provides you some views of our modeling results in tidal simulation and wind- and buoyancy-driven circulation. Monthly climatological hydrographic database were built in collaboration with scientists at WHOI and in China.

FVCOM Global

“Why don’t we apply FVCOM to the global Ocean” is a common question asked by many scientists, since the unstructured grid can easily resolve the singularity at the North Pole and also provides a better linkage between the basin ocean to the coastal ocean. FVCOM has been configured for the global scale with varying horizontal resolution of ~25-50 km. The model uses the generalized terrian-following coordinate in the vertical, with a total of 46 layers -10 uniform layers in the surface and bottom boundary layers, respectively.

Arctic Ocean FVCOM

The coastal geometry of the Artic ocean is marvelously complex. For a domain such as this, an unstructured model like FVCOM is necessary to resolve the circulation. A high-resolution Arctic Ocean FVCOM was configured using unstructured meshes in spherical coordinates. The singularity issue at the North Pole is not an issue with or finite volume methodology. A sea ice model is included and a spinup of the circulation is underway. Several applications of the Arctic Ocean model are planned. Given the changing climate, the Arctic Ocean will play a critical role in ocean circulation, ecosystem change, and international politics.

Non-hydrostatic FVCOM

A non-hydrostatic version of FVCOM is being developed by adding a core non-hydrostatic module in the existing FVCOM. Both projection and pressure-correction methods are coded in the unstructured grid and the Poisson equation for non-hydrostatic pressure is solved by the finite-volume method with the state-of-the art solvers.

Posted on January 10, 2014