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Notes from Sept 17
The primary goal of this meeting was to announce the release of a
suite of biogeochemical
model formulations coded into MOM4. These include implementations
in the version of OM3 being developed for the coupled model, and a
preliminary version of OM1. See the HOWTO
document for more details. Additionally, we were able to:
Progress since June 5
-
Within OBMDT:
- Added the capacity to run diagnostic tracers in the ocean model.
such tracers are not advected and diffused, but are updated at each
time step in the
model infrastructure.
- The capability of coupling the biogeochemistry to the physics
through effect of chlorophyll on the penetration of shortwave radiation.
- A preliminary ecological model was developed.
- Coded a "tracer friendly" advection scheme that is monotonic and
positive definite to help prevent "digging" of tracers. It is a
Multi-Dimensional Flux Limiting scheme utilizing the Sweby limiter (mdfl-sweby),
which is third-order accurate. The "mdfl-sweby" was found to be 5-10%
slower than the quicker scheme but is extremely beneficial for tracers near their numerical
stability edge (such as silicate for its large gradients, and phytoplankton
for their large source terms). This was done
with considerable help of Alistair Adcroft.
- Added the capacity to run prognostic tracers with constant initial
fields, a limiting concentration on which neutral physics will act, a
limiting concentration at which "quicker" advection reverts to
"upwind", and a scenario in which the only
explicit physical process allowed to act on a given tracer is
advection (useful for comparing advection schemes).
- OM3 - ocean physics nearing frozen version (1° globally,
1/3° meridionally tropics)
- Preprocessing tools available to facilitate the creation of new
grids, boundary conditions and initial conditions
- Convergence to a single field mananger for the atmosphere
Synergystic activities:
Re-established Priorities
- Incorporating CFCs into MOM4 for public release in October. This will also allow critical tests on circulation.
- A working version of OM1 in order to reproduce the OCMIP experiments
- The coupler for coupled atmosphere-ocean carbon cycling studies
- Prognostic ecosystem rozen for re-anaysis and prediction runs by April.
Revised Timeline
|
Coding |
Due |
Simulations |
Due |
|
Generic Tracer management |
Done - Slater |
|
|
|
OCMIP2 Biotic |
Done - Slater |
|
|
|
Full restoring BGC |
Done - Dunne |
Start full restoring BGC runs |
10/1/2003 - Dunne |
|
|
|
New OM1 |
10/1/2003 - Simeon |
|
Phytoplankton BGC |
Preliminary done - Dunne |
|
|
|
|
|
Start Phytoplankton BGC runs |
Done - Dunne |
|
OCMIP2 CFCs |
10/10/2003 - Slater |
|
|
|
OCMIP2 CFCs in HIM |
12/1/2003 - Arbic |
|
|
|
OCMIP2 abiotic |
12/1/2003 - Slater |
|
|
|
Manager for coupler |
11/1/2003 – Slater but depends on modeling services |
|
|
|
|
|
1st evaluation of restoring model |
10/15/2003 - OBMDT |
|
|
|
1st evaluation of phytoplankton BGC seasonality |
11/1/2003 - OBMDT |
|
HadOCC BGC |
12/1/2003 |
|
|
|
|
|
Phytoplankton BGC run in OMIP framework |
12/15/2003 - Sweeney |
|
OCMIP2 abiotic in HIM |
1/1/2004 – Sweeney, Arbic |
|
|
|
|
|
HadOCC run in OM3 compared to Phytoplankton BGC |
2/15/2004 - OBMDT |
|
|
|
Choose model for coupled run |
4/15/2004 - OBMDT |
Definitions:
|
Model |
Tracer Setup |
Used for: |
|
OCMIP2 CFC (Implemented in MOM3) |
CFC-11,12 |
Understanding ocean ventilation on moderate time scales (10-50 years) |
|
OCMIP2 Abiotic (Implemented in MOM3) |
Dissolved inorganic carbon (DIC), DIC14,
Alkalinity~Salinity
|
Understanding ventilation of ocean on range of time scales (10-1000 years), predicting uptake of anthropogenic carbon. |
|
OCMIP2 Biotic (Implemented in MOM3 and MOM4) |
Phosphate, Dissolved Organic Phosphorus, oxygen, DIC, alkalinity Biological production diagnosed from restoring phosphate to surface data. Constant partitioning of production into particulate and dissolved matter. |
Diagnosing new production, particle export. Estimating size of carbon pumps. Fertilization studies. |
|
New diagnostic model (Implemented in MOM3) |
Phosphate, nitrate, ammonium, 3 types of dissolved organic matter, oxygen, silicate, DIC, alkalinity. Biological production diagnosed from restoring nitrogen, phosphorus, silicon and alkalinity species to surface data. Partitioning of production depends on diagnosed ecosystem structure. |
Allows diagnostic primary production, chlorophyll, ecosystem structure, nitrogen fixation. Simulation of dissolved organic matter. |
|
New prognostic model |
Same as new diagnostic but with iron, large and small phytoplankton. Biological production predicted from nutrient availability and light. |
Allows prediction of ecosystem changes under climate change. Simulating biogeochemical variability. Predicting impact of iron fertilization directly. |
|
HadOCC |
Nitrogen species, phytoplankton, zooplankton, DIC, Alkalinity, oxygen. Biological production predicted from nutrient availability and light. |
Same as new prognostic with exception of iron cycle. |