+ The goal of the Climate Ecosystem and Fisheries Initiative (CEFI) is to provide information about past and future conditions for US coastal regions. + Models need to be at a sufficient resolution to represent general coastal processes (on the order of 8-10 km horizontal resolution, + although the grid may be of finer scale in the near future). In addition to historical simulation, seasonal forecasts (out to 1 year), + decadal forecasts (out to 10 years) and long term projections (out to 2100) will be made for several regions, including: +
+ Currently, the regional MOM6 output can be accessed through the PSL THREDDS server. + Users have the flexibility to choose their preferred method of data retrieval from this server. + Additionally, an alternative option involving AWS cloud storage is under consideration and may become available in the near future. + This option is currently undergoing testing. For direct access to the THREDDS server, go to the + catalog directly. +
++ + To access/download the data, the CEFI portal + model data access + offer couple different options. + +
+ Regional models have some benefits over global models, including being able to represent finer scale features more rapidly. + They can also be “tuned” (have their many parameter values adjusted) to better represent conditions in the region of interest. + While regional ocean models including the Regional Ocean Modeling System (ROMS) and Finite Volume Coastal Ocean Model (FVCOM) + have been developed and used for many years, NOAA did not have regional ocean model capability. Building off the expertise in + developing global models, the regional version of MOM6 has been developed particularly with fishery and ocean habitat applications in mind. +
++ The climate system is often simulated by coupling models representing different parts of the earth system together. + Common components include the atmosphere, ocean, sea ice, land, land vegetation, and ocean biogeochemistry. + Terminology varies depending on which components are included: +
++ The Modular Ocean Model, version 6 (MOM6) is the ocean component of the NOAA Geophysical Fluid Dynamics Laboratory + (GFDL)’s earth system model (ESM4). This model has been developed over several decades and is one of the world’s + premier ESMs. The MOM6 ocean model simulates physical ocean dynamics like ocean currents, temperature, and salinity, + and can be coupled to a sea ice model (SIS2) that simulates formation and melting of sea ice and an ocean biogeochemical + model (COBALT) that simulates nutrient cycling and lower trophic level dynamics. +
++ While the global version of MOM6 has existed for many decades, the regional version has been developed much more recently + and is still being improved. Simulating open lateral boundaries is a complex task, and it took time to add these capabilities + in a manner compatible with the global MOM6 configuration. A description of how these boundary conditions are implemented can + be found in the documentation paper for the northwest Atlantic implementation. Both the global and regional implementations use the same underlying code base. +
++ A regional ocean model always requires external input to prescribe what is happening at the surface and lateral boundaries; + that input usually comes from the output of a larger- and coarser-scale global model or a reanalysis, which combines a model + with observations. These boundary conditions play a strong driving role in any simulation, and a regional model will inherit + some of both the skill and biases of its parent model/reanalysis. A regional model is more than just a high-resolution filter + for the parent model; it can resolve dynamics not possible at a coarser scale, and also can add new processes not present in + the parent (for example, extra biological complexity). This can alleviate biases from the parent model. But at the same time, + some biases can be amplified in the regional model output. The resulting features in a regional model will always be a combination + of the parent model’s dynamics and its own internal dynamics. +
++ Different types of regional simulations can be run by pairing a regional MOM6 domain with different types of parent + models/datasets for its atmospheric and boundary condition forcing. The terminology for these different simulation + types -- historical, forecast, projection, etc. -- is not standardized across the field and can be confusing. + Here's a brief summary of the CEFI simulations and our chosen terminology: +
++ Historical simulations: CEFI's historical simulations attempt to simulate real-world conditions in the recent past. + They derive their input forcing from a global reanalysis. Reanalyses combine model dynamics and observations using + a process known as data assimilation. Regional historical runs can be used to measure the skill of the model compared + to observations. They also play many roles in research and ecosystem management: to fill in spatiotemporal gaps in + observations, provide a physical basis to drive fisheries and other ecosystem models, initialize forecasts, and many more. + Note that our historical simulations do not themselves assimilate observations; they are simply forced by a data-assimilative + parent model. Sometimes historical simulations are referred to as “hindcasts”. +
++ Note on terminology: In some contexts, "historical" ESM or climate model simulations can refer the historical experiment + output of an earth system model intercomparison project (e.g., [CMIP6](https://doi.org/10.5194/gmd-9-1937-2016)). + Unlike a reanalysis model, these ESMs are not directly tied to observations on initialization. They usually start from + a simulation designed to bring the internal dynamics into equilibrium under pre-industrial conditions (i.e. letting the + model approach its long-term average climate). They do not assimilate data and are tied to specific time periods only by + prescribed greenhouse gas emissions and atmospheric aerosols. A skillful ESM/GCM will capture real-world statistical variability + across interannual and decadal scales, but will not have a year-to-year match to the real world. For example, they will produce + warm or cold events like ENSO, but not specific heat waves when they occur in the real world. The CEFI suite does not currently + include this type of CMIP historical experiment simulation. +
++ Long-term forecasts: Decadal forecasts that are initialized once per year and extend to 10 years will be added. +
++ Forecast ensembles: Due to the chaotic nature of the climate system, very small differences in conditions at one + time can lead to large differences in future values. The SPEAR simulations account for this by running multiple + forecast simulations with slight differences in their initial conditions, producing an ensemble of forecasts that + can be used to quantify the uncertainty of predictions. The CEFI regional seasonal forecasts downscale 10 of these ensemble members. +
++ Note on terminology: Forecasts are usually run starting from near-present conditions to predict the future. + But they can also be initialized from past conditions. This type of forecast is sometimes referred to as a + retrospective forecast/reforecast. These differ from the historical simulations because they are not tied + to real-world data during the simulation period, only at their initialization time. The primary purpose of + these simulations is to assess the skill of a forecast model by comparing the forecasts to real-world data + (or to a reanalysis or historical simulation). +
++ Carbon, Ocean Biogeochemistry and Lower Trophics (COBALT) (version 2 COBALTv2, with enhancements for regional MOM6) + is the ocean biogeochemical model associated with MOM6. COBALTv3 includes 40 state variables that simulate nutrient + cycling for carbon, alkalinity, oxygen, nitrogen, phosphorus, iron, silica, calcium carbonate, and lithogenic minerals, + as well as the food web dynamics of phytoplankton and zooplankton. +
++ The COBALT source code is included within the MOM6 component, and when active there is two-way feedback between ocean + and biogeochemical state variables (for example, temperature influences many of the biological rate parameters, while + phytoplankton biomass impacts solar radiation reaching and hence heating the water column). +
++ The regional MOM6 simulations use z* as the vertical coordinate. It’s essentially a height (z) based system but + shares some similarity with a terrain following (σ) coordinate system. Indeed, z* only differs from z when the + free-surface elevation is non-zero.The coordinate system transforms the moving boundary problem of the oceans free surface into a fixed domain. +
++ Alistair Adcroft, A., Jean-Michel Campin, J.-M., 2004: Rescaled height coordinates for accurate representation of + free-surface flows in ocean circulation models, Ocean Modelling, 7, 3–4,269-284, https://doi.org/10.1016/j.ocemod.2003.09.003. +
++ Note that this is the model coordinate system - output is archived at set depth levels. +
+The goal of the Climate Ecosystem and Fisheries Initiative (CEFI) is to provide @@ -183,4 +163,3 @@