Problem Set 3: Introduction to Ocean Box Modeling
1. Write the steady-state matrix equation for phosphorus for the 3-box model shown below (you do not have to
solve the equations):
1
surface
Q12
Q21
Fp12
2
intermediate
Q32
Q23
3
Fp13
deep
Where Q signifies flux of water and Fp signifies a particulate flux. Note your units!
2. Explore the "Harvardton Bears" 3-box ocean model. You are given two Microsoft Excel 5.0 files which
contain models for S, P, Alk, CO2, C13, and C14. The goal is to explore the model a little by changing some
parameters.
The model is best viewed on a color monitor. Color coding helps you identify the uses of cells:
Things you can change are marked in boldface dark blue. These include water fluxes between boxes
(subject to the conditions that water fluxes must be balanced and certain "forbidden" outcomes are avoided you will be warned when these aconditions are violated), phosphorus concentrations in the boxes, the Redfield
Ratios, and the gas exchange piston velocity.
The model is arranged by modules in a vertical sense, so that any changes in a module affect modules below
but not those above. (The exception to this is the oxygen model at the bottom, which only depends on the
phosphorus and salinity modules.
Water fluxes are given in Sverdrups (106 m3/sec). Concentrations are in µmol/kg (except for 14C and salinity)
.
Important model outputs are shown in magenta.
Other color codes indicate different types of fluxes: e.g., water fluxes are shown in cyan (light blue) and
particle fluxes are shown in green.
Temperature and salinity are not explicitly changable in the model, although one of the files assumes warmer
and fresher conditions and the other assumes saltier and cooler conditions.
Each time you make a set of changes, you must press Command-Option-g (goal seek) to solve the CO2system (CO2, C13, C14) equations. All other calculations occur immediately.
Your goal here is to explore the sensitivity of the model to small changes in conditions such as surface
phosphorus and water fluxes, and to report your findings in the context of the ocean carbon system. I am only
expecting a couple of pages for this report.