Ocean Biogeochemical Modelling Environment

Description

OceanBioME was developed with generous support from the Cambridge Centre for Climate Repair CCRC and the Gordon and Betty Moore Foundation as a tool to study the effectiveness and impacts of ocean carbon dioxide removal (CDR) strategies.

OceanBioME is a flexible modelling environment written in Julia for modelling the coupled interactions between ocean biogeochemistry, carbonate chemistry, and physics. OceanBioME can be run as a stand-alone box model, or coupled with Oceananigans.jl to run as a 1D column model or with 2 and 3D physics.

Installation:

First, download and install Julia

From the Julia prompt (REPL), type:

julia> using Pkg
julia> Pkg.add("OceanBioME")

Running your first model

As a simple example lets run a Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) model in a two-dimensional simulation of a buoyancy front:

using OceanBioME, Oceananigans
using Oceananigans.Units

grid = RectilinearGrid(CPU(), size=(256, 32), extent=(500, 100), topology=(Bounded, Flat, Bounded))

biogeochemistry = NutrientPhytoplanktonZooplanktonDetritus(; grid, open_bottom=true)

model = NonhydrostaticModel(; grid, biogeochemistry, buoyancy=BuoyancyTracer(), tracers=:b, advection=WENO(; grid), closure = AnisotropicMinimumDissipation())

bᵢ(x, y, z) = ifelse(x < 250, 1e-4, 1e-3)

set!(model, b = bᵢ, N = 5.0, P = 0.1, Z = 0.1, T = 18.0)

simulation = Simulation(model; Δt=1.0, stop_time=3hours)

wizard = TimeStepWizard(cfl=0.3, max_change=1.5)

simulation.callbacks[:wizard] = Callback(wizard, IterationInterval(1))

simulation.output_writers[:tracers] = JLD2OutputWriter(model, model.tracers, filename = "buoyancy_front.jld2", schedule = TimeInterval(1minute), overwrite_existing=true)

run!(simulation)

using CairoMakie
b = FieldTimeSeries("buoyancy_front.jld2", "b")
P = FieldTimeSeries("buoyancy_front.jld2", "P")

n = Observable(1)

b_lims = (minimum(b), maximum(b))
P_lims = (minimum(P), maximum(P))

b_plt = @lift b[1:grid.Nx, 1, 1:grid.Nz, $n]
P_plt = @lift P[1:grid.Nx, 1, 1:grid.Nz, $n]

fig = Figure(resolution = (1600, 160 * 4))

supertitle = Label(fig[0, :], "t = 0.0")

ax1 = Axis(fig[1, 1], xlabel = "x (m)", ylabel = "z (m)", title = "Buouyancy pertubation (m / s)", width = 1400)
ax2 = Axis(fig[2, 1], xlabel = "x (m)", ylabel = "z (m)", title = "Phytoplankton concentration (mmol N / m³)", width = 1400)

hm1 = heatmap!(ax1, xnodes(grid, Center(), Center(), Center())[1:grid.Nx], znodes(grid, Center(), Center(), Center())[1:grid.Nz], b_plt, colorrange = b_lims, colormap = :batlow, interpolate=true)
hm2 = heatmap!(ax2, xnodes(grid, Center(), Center(), Center())[1:grid.Nx], znodes(grid, Center(), Center(), Center())[1:grid.Nz], P_plt, colorrange = P_lims, colormap = Reverse(:bamako), interpolate=true)

Colorbar(fig[1, 2], hm1)
Colorbar(fig[2, 2], hm2)

record(fig, "buoyancy_front.gif", 1:length(b.times)) do i
    n[] = i
    msg = string("Plotting frame ", i, " of ", length(b.times))
    print(msg * " \r")
    supertitle.text = "t=$(prettytime(b.times[i]))"
end

In this example OceanBioME is providing the biogeochemistry and the remainder is taken care of by Oceananigans. For comprehensive documentation of the physics modelling see Oceananigans' Documentation, and for biogeochemistry and other features we provide read below.

Documentation

See the documentation for full description and examples.