Wind- and convection-driven mixing in an ocean surface boundary layer

This example simulates mixing by three-dimensional turbulence in an ocean surface boundary layer driven by atmospheric winds and convection. It demonstrates:

  • How to set-up a grid with varying spacing in the vertical direction
  • How to use the SeawaterBuoyancy model for buoyancy with TEOS10EquationOfState.
  • How to use a turbulence closure for large eddy simulation.
  • How to use a function to impose a boundary condition.

Install dependencies

First let's make sure we have all required packages installed.

using Pkg
pkg"add Oceananigans, CairoMakie, SeawaterPolynomials"

We start by importing all of the packages and functions that we'll need for this example.

using Oceananigans
using Oceananigans.Units

using Random
using Printf
using CairoMakie
using SeawaterPolynomials.TEOS10: TEOS10EquationOfState

The grid

We use 128²×64 grid points with 1 m grid spacing in the horizontal and varying spacing in the vertical, with higher resolution closer to the surface. Here we use a stretching function for the vertical nodes that maintains relatively constant vertical spacing in the mixed layer, which is desirable from a numerical standpoint:

Nx = Ny = 128    # number of points in each of horizontal directions
Nz = 64          # number of points in the vertical direction

Lx = Ly = 128    # (m) domain horizontal extents
Lz = 64          # (m) domain depth

refinement = 1.2 # controls spacing near surface (higher means finer spaced)
stretching = 12  # controls rate of stretching at bottom

# Normalized height ranging from 0 to 1
h(k) = (k - 1) / Nz

# Linear near-surface generator
ζ₀(k) = 1 + (h(k) - 1) / refinement

# Bottom-intensified stretching function
Σ(k) = (1 - exp(-stretching * h(k))) / (1 - exp(-stretching))

# Generating function
z_interfaces(k) = Lz * (ζ₀(k) * Σ(k) - 1)

grid = RectilinearGrid(GPU(),
                       size = (Nx, Nx, Nz),
                       x = (0, Lx),
                       y = (0, Ly),
                       z = z_interfaces)
128×128×64 RectilinearGrid{Float64, Periodic, Periodic, Bounded} on CUDAGPU with 3×3×3 halo
├── Periodic x ∈ [0.0, 128.0) regularly spaced with Δx=1.0
├── Periodic y ∈ [0.0, 128.0) regularly spaced with Δy=1.0
└── Bounded  z ∈ [-64.0, 0.0] variably spaced with min(Δz)=0.833413, max(Δz)=1.96618

We plot vertical spacing versus depth to inspect the prescribed grid stretching:

fig = Figure(size=(1200, 800))
ax = Axis(fig[1, 1], ylabel = "z (m)", xlabel = "Vertical spacing (m)")

lines!(ax, zspacings(grid, Center()))
scatter!(ax, zspacings(grid, Center()))

fig

Buoyancy that depends on temperature and salinity

We use the SeawaterBuoyancy model with the TEOS10 equation of state,

ρₒ = 1026 # kg m⁻³, average density at the surface of the world ocean
equation_of_state = TEOS10EquationOfState(reference_density=ρₒ)
buoyancy = SeawaterBuoyancy(; equation_of_state)
SeawaterBuoyancy{Float64}:
├── gravitational_acceleration: 9.80665
└── equation_of_state: BoussinesqEquationOfState{Float64}

Boundary conditions

We calculate the surface temperature flux associated with surface cooling of 200 W m⁻², reference density ρₒ, and heat capacity cᴾ,

Q = 200   # W m⁻², surface _heat_ flux
cᴾ = 3991 # J K⁻¹ kg⁻¹, typical heat capacity for seawater

Jᵀ = Q / (ρₒ * cᴾ) # K m s⁻¹, surface _temperature_ flux
4.884283985946938e-5

Finally, we impose a temperature gradient dTdz both initially (see "Initial conditions" section below) and at the bottom of the domain, culminating in the boundary conditions on temperature,

dTdz = 0.01 # K m⁻¹

T_bcs = FieldBoundaryConditions(top = FluxBoundaryCondition(Jᵀ),
                                bottom = GradientBoundaryCondition(dTdz))
Oceananigans.FieldBoundaryConditions, with boundary conditions
├── west: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── east: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── south: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── north: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── bottom: GradientBoundaryCondition: 0.01
├── top: FluxBoundaryCondition: 4.88428e-5
└── immersed: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)

Note that a positive temperature flux at the surface of the ocean implies cooling. This is because a positive temperature flux implies that temperature is fluxed upwards, out of the ocean.

For the velocity field, we imagine a wind blowing over the ocean surface with an average velocity at 10 meters u₁₀, and use a drag coefficient cᴰ to estimate the kinematic stress (that is, stress divided by density) exerted by the wind on the ocean:

u₁₀ = 10  # m s⁻¹, average wind velocity 10 meters above the ocean
cᴰ = 2e-3 # dimensionless drag coefficient
ρₐ = 1.2  # kg m⁻³, approximate average density of air at sea-level
τx = - ρₐ / ρₒ * cᴰ * u₁₀ * abs(u₁₀) # m² s⁻²
-0.00023391812865497074

The boundary conditions on u are thus

u_bcs = FieldBoundaryConditions(top = FluxBoundaryCondition(τx))
Oceananigans.FieldBoundaryConditions, with boundary conditions
├── west: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── east: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── south: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── north: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── bottom: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── top: FluxBoundaryCondition: -0.000233918
└── immersed: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)

For salinity, S, we impose an evaporative flux of the form

@inline Jˢ(x, y, t, S, evaporation_rate) = - evaporation_rate * S # [salinity unit] m s⁻¹

where S is salinity. We use an evaporation rate of 1 millimeter per hour,

evaporation_rate = 1e-3 / hour # m s⁻¹
2.7777777777777776e-7

We build the Flux evaporation BoundaryCondition with the function , indicating that depends on salinity S and passing the parameter evaporation_rate,

evaporation_bc = FluxBoundaryCondition(Jˢ, field_dependencies=:S, parameters=evaporation_rate)
FluxBoundaryCondition: ContinuousBoundaryFunction Jˢ at (Nothing, Nothing, Nothing)

The full salinity boundary conditions are

S_bcs = FieldBoundaryConditions(top=evaporation_bc)
Oceananigans.FieldBoundaryConditions, with boundary conditions
├── west: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── east: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── south: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── north: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── bottom: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)
├── top: FluxBoundaryCondition: ContinuousBoundaryFunction Jˢ at (Nothing, Nothing, Nothing)
└── immersed: DefaultBoundaryCondition (FluxBoundaryCondition: Nothing)

Model instantiation

We fill in the final details of the model here, i.e., Coriolis forces, and the AnisotropicMinimumDissipation closure for large eddy simulation to model the effect of turbulent motions at scales smaller than the grid scale that are not explicitly resolved.

model = NonhydrostaticModel(; grid, buoyancy,
                            tracers = (:T, :S),
                            coriolis = FPlane(f=1e-4),
                            closure = AnisotropicMinimumDissipation(),
                            boundary_conditions = (u=u_bcs, T=T_bcs, S=S_bcs))
NonhydrostaticModel{GPU, RectilinearGrid}(time = 0 seconds, iteration = 0)
├── grid: 128×128×64 RectilinearGrid{Float64, Periodic, Periodic, Bounded} on CUDAGPU with 3×3×3 halo
├── timestepper: RungeKutta3TimeStepper
├── advection scheme: Centered(order=2)
├── tracers: (T, S)
├── closure: AnisotropicMinimumDissipation{ExplicitTimeDiscretization, @NamedTuple{T::Float64, S::Float64}, Float64, Nothing}
├── buoyancy: SeawaterBuoyancy with g=9.80665 and BoussinesqEquationOfState{Float64} with ĝ = NegativeZDirection()
└── coriolis: FPlane{Float64}(f=0.0001)

Note: To use the Smagorinsky-Lilly turbulence closure (with a constant model coefficient) rather than AnisotropicMinimumDissipation, use closure = SmagorinskyLilly() in the model constructor.

Initial conditions

Our initial condition for temperature consists of a linear stratification superposed with random noise damped at the walls, while our initial condition for velocity consists only of random noise.

# Random noise damped at top and bottom
Ξ(z) = randn() * z / model.grid.Lz * (1 + z / model.grid.Lz) # noise

# Temperature initial condition: a stable density gradient with random noise superposed.
Tᵢ(x, y, z) = 20 + dTdz * z + dTdz * model.grid.Lz * 1e-6 * Ξ(z)

# Velocity initial condition: random noise scaled by the friction velocity.
uᵢ(x, y, z) = sqrt(abs(τx)) * 1e-3 * Ξ(z)

# `set!` the `model` fields using functions or constants:
set!(model, u=uᵢ, w=uᵢ, T=Tᵢ, S=35)

Setting up a simulation

We set-up a simulation with an initial time-step of 10 seconds that stops at 2 hours, with adaptive time-stepping and progress printing.

simulation = Simulation(model, Δt=10, stop_time=2hours)
Simulation of NonhydrostaticModel{GPU, RectilinearGrid}(time = 0 seconds, iteration = 0)
├── Next time step: 10 seconds
├── Elapsed wall time: 0 seconds
├── Wall time per iteration: NaN days
├── Stop time: 2 hours
├── Stop iteration: Inf
├── Wall time limit: Inf
├── Minimum relative step: 0.0
├── Callbacks: OrderedDict with 4 entries:
│   ├── stop_time_exceeded => 4
│   ├── stop_iteration_exceeded => -
│   ├── wall_time_limit_exceeded => e
│   └── nan_checker => }
├── Output writers: OrderedDict with no entries
└── Diagnostics: OrderedDict with no entries

The TimeStepWizard helps ensure stable time-stepping with a Courant-Freidrichs-Lewy (CFL) number of 1.0.

wizard = TimeStepWizard(cfl=1, max_change=1.1, max_Δt=1minute)
simulation.callbacks[:wizard] = Callback(wizard, IterationInterval(10))
Callback of TimeStepWizard(cfl=1.0, max_Δt=60.0, min_Δt=0.0) on IterationInterval(10)

Nice progress messaging is helpful:

# Print a progress message
progress_message(sim) = @printf("Iteration: %04d, time: %s, Δt: %s, max(|w|) = %.1e ms⁻¹, wall time: %s\n",
                                iteration(sim), prettytime(sim), prettytime(sim.Δt),
                                maximum(abs, sim.model.velocities.w), prettytime(sim.run_wall_time))

add_callback!(simulation, progress_message, IterationInterval(40))

We then set up the simulation:

Output

We use the JLD2Writer to save $x, z$ slices of the velocity fields, tracer fields, and eddy diffusivities. The prefix keyword argument to JLD2Writer indicates that output will be saved in ocean_wind_mixing_and_convection.jld2.

# Create a NamedTuple with eddy viscosity
eddy_viscosity = (; νₑ = model.diffusivity_fields.νₑ)

filename = "ocean_wind_mixing_and_convection"

simulation.output_writers[:slices] =
    JLD2Writer(model, merge(model.velocities, model.tracers, eddy_viscosity),
               filename = filename * ".jld2",
               indices = (:, grid.Ny/2, :),
               schedule = TimeInterval(1minute),
               overwrite_existing = true)
JLD2Writer scheduled on TimeInterval(1 minute):
├── filepath: ocean_wind_mixing_and_convection.jld2
├── 6 outputs: (u, v, w, T, S, νₑ)
├── array type: Array{Float32}
├── including: [:grid, :coriolis, :buoyancy, :closure]
├── file_splitting: NoFileSplitting
└── file size: 63.4 KiB

We're ready:

run!(simulation)
[ Info: Initializing simulation...
Iteration: 0000, time: 0 seconds, Δt: 11 seconds, max(|w|) = 1.3e-05 ms⁻¹, wall time: 0 seconds
[ Info:     ... simulation initialization complete (29.616 seconds)
[ Info: Executing initial time step...
[ Info:     ... initial time step complete (5.793 seconds).
Iteration: 0040, time: 7 minutes, Δt: 8.309 seconds, max(|w|) = 2.5e-05 ms⁻¹, wall time: 36.367 seconds
Iteration: 0080, time: 11.183 minutes, Δt: 4.903 seconds, max(|w|) = 7.6e-03 ms⁻¹, wall time: 36.889 seconds
Iteration: 0120, time: 14.069 minutes, Δt: 3.899 seconds, max(|w|) = 2.2e-02 ms⁻¹, wall time: 37.414 seconds
Iteration: 0160, time: 16.602 minutes, Δt: 3.979 seconds, max(|w|) = 2.5e-02 ms⁻¹, wall time: 37.878 seconds
Iteration: 0200, time: 19 minutes, Δt: 4.103 seconds, max(|w|) = 2.8e-02 ms⁻¹, wall time: 38.397 seconds
Iteration: 0240, time: 21.664 minutes, Δt: 3.820 seconds, max(|w|) = 3.0e-02 ms⁻¹, wall time: 38.886 seconds
Iteration: 0280, time: 24 minutes, Δt: 3.700 seconds, max(|w|) = 3.1e-02 ms⁻¹, wall time: 39.381 seconds
Iteration: 0320, time: 26.302 minutes, Δt: 3.608 seconds, max(|w|) = 2.3e-02 ms⁻¹, wall time: 39.863 seconds
Iteration: 0360, time: 28.642 minutes, Δt: 3.562 seconds, max(|w|) = 2.6e-02 ms⁻¹, wall time: 40.335 seconds
Iteration: 0400, time: 30.930 minutes, Δt: 3.488 seconds, max(|w|) = 2.9e-02 ms⁻¹, wall time: 40.900 seconds
Iteration: 0440, time: 33.116 minutes, Δt: 3.413 seconds, max(|w|) = 3.1e-02 ms⁻¹, wall time: 41.514 seconds
Iteration: 0480, time: 35.269 minutes, Δt: 3.233 seconds, max(|w|) = 3.8e-02 ms⁻¹, wall time: 42.029 seconds
Iteration: 0520, time: 37.250 minutes, Δt: 3.026 seconds, max(|w|) = 4.0e-02 ms⁻¹, wall time: 42.491 seconds
Iteration: 0560, time: 39.098 minutes, Δt: 2.918 seconds, max(|w|) = 3.9e-02 ms⁻¹, wall time: 42.990 seconds
Iteration: 0600, time: 41 minutes, Δt: 3.103 seconds, max(|w|) = 3.4e-02 ms⁻¹, wall time: 43.447 seconds
Iteration: 0640, time: 43.000 minutes, Δt: 3.073 seconds, max(|w|) = 3.2e-02 ms⁻¹, wall time: 43.979 seconds
Iteration: 0680, time: 44.933 minutes, Δt: 2.951 seconds, max(|w|) = 3.7e-02 ms⁻¹, wall time: 44.436 seconds
Iteration: 0720, time: 46.832 minutes, Δt: 2.920 seconds, max(|w|) = 4.0e-02 ms⁻¹, wall time: 44.936 seconds
Iteration: 0760, time: 48.742 minutes, Δt: 2.960 seconds, max(|w|) = 5.8e-02 ms⁻¹, wall time: 45.444 seconds
Iteration: 0800, time: 50.578 minutes, Δt: 2.833 seconds, max(|w|) = 4.5e-02 ms⁻¹, wall time: 46.081 seconds
Iteration: 0840, time: 52.424 minutes, Δt: 2.763 seconds, max(|w|) = 4.0e-02 ms⁻¹, wall time: 46.942 seconds
Iteration: 0880, time: 54.236 minutes, Δt: 2.782 seconds, max(|w|) = 5.1e-02 ms⁻¹, wall time: 47.859 seconds
Iteration: 0920, time: 56 minutes, Δt: 2.741 seconds, max(|w|) = 5.7e-02 ms⁻¹, wall time: 48.595 seconds
Iteration: 0960, time: 57.831 minutes, Δt: 2.738 seconds, max(|w|) = 4.0e-02 ms⁻¹, wall time: 49.466 seconds
Iteration: 1000, time: 59.664 minutes, Δt: 2.821 seconds, max(|w|) = 4.7e-02 ms⁻¹, wall time: 50.337 seconds
Iteration: 1040, time: 1.024 hours, Δt: 2.689 seconds, max(|w|) = 5.6e-02 ms⁻¹, wall time: 51.022 seconds
Iteration: 1080, time: 1.053 hours, Δt: 2.666 seconds, max(|w|) = 5.3e-02 ms⁻¹, wall time: 52.004 seconds
Iteration: 1120, time: 1.082 hours, Δt: 2.728 seconds, max(|w|) = 5.1e-02 ms⁻¹, wall time: 52.915 seconds
Iteration: 1160, time: 1.112 hours, Δt: 2.527 seconds, max(|w|) = 4.6e-02 ms⁻¹, wall time: 53.703 seconds
Iteration: 1200, time: 1.139 hours, Δt: 2.635 seconds, max(|w|) = 5.1e-02 ms⁻¹, wall time: 54.409 seconds
Iteration: 1240, time: 1.167 hours, Δt: 2.461 seconds, max(|w|) = 4.8e-02 ms⁻¹, wall time: 54.914 seconds
Iteration: 1280, time: 1.196 hours, Δt: 2.673 seconds, max(|w|) = 5.1e-02 ms⁻¹, wall time: 55.447 seconds
Iteration: 1320, time: 1.225 hours, Δt: 2.610 seconds, max(|w|) = 5.0e-02 ms⁻¹, wall time: 55.932 seconds
Iteration: 1360, time: 1.254 hours, Δt: 2.653 seconds, max(|w|) = 5.3e-02 ms⁻¹, wall time: 56.425 seconds
Iteration: 1400, time: 1.283 hours, Δt: 2.573 seconds, max(|w|) = 4.3e-02 ms⁻¹, wall time: 56.927 seconds
Iteration: 1440, time: 1.311 hours, Δt: 2.655 seconds, max(|w|) = 5.7e-02 ms⁻¹, wall time: 57.417 seconds
Iteration: 1480, time: 1.339 hours, Δt: 2.436 seconds, max(|w|) = 6.2e-02 ms⁻¹, wall time: 57.947 seconds
Iteration: 1520, time: 1.366 hours, Δt: 2.567 seconds, max(|w|) = 5.7e-02 ms⁻¹, wall time: 58.414 seconds
Iteration: 1560, time: 1.394 hours, Δt: 2.504 seconds, max(|w|) = 5.7e-02 ms⁻¹, wall time: 58.944 seconds
Iteration: 1600, time: 1.422 hours, Δt: 2.585 seconds, max(|w|) = 5.2e-02 ms⁻¹, wall time: 59.430 seconds
Iteration: 1640, time: 1.450 hours, Δt: 2.598 seconds, max(|w|) = 5.7e-02 ms⁻¹, wall time: 59.975 seconds
Iteration: 1680, time: 1.478 hours, Δt: 2.381 seconds, max(|w|) = 6.4e-02 ms⁻¹, wall time: 1.008 minutes
Iteration: 1720, time: 1.503 hours, Δt: 2.315 seconds, max(|w|) = 5.4e-02 ms⁻¹, wall time: 1.016 minutes
Iteration: 1760, time: 1.529 hours, Δt: 2.388 seconds, max(|w|) = 5.5e-02 ms⁻¹, wall time: 1.025 minutes
Iteration: 1800, time: 1.555 hours, Δt: 2.381 seconds, max(|w|) = 5.8e-02 ms⁻¹, wall time: 1.033 minutes
Iteration: 1840, time: 1.581 hours, Δt: 2.432 seconds, max(|w|) = 6.4e-02 ms⁻¹, wall time: 1.041 minutes
Iteration: 1880, time: 1.607 hours, Δt: 2.440 seconds, max(|w|) = 6.7e-02 ms⁻¹, wall time: 1.049 minutes
Iteration: 1920, time: 1.634 hours, Δt: 2.445 seconds, max(|w|) = 7.9e-02 ms⁻¹, wall time: 1.058 minutes
Iteration: 1960, time: 1.661 hours, Δt: 2.440 seconds, max(|w|) = 7.4e-02 ms⁻¹, wall time: 1.066 minutes
Iteration: 2000, time: 1.687 hours, Δt: 2.355 seconds, max(|w|) = 6.3e-02 ms⁻¹, wall time: 1.074 minutes
Iteration: 2040, time: 1.713 hours, Δt: 2.351 seconds, max(|w|) = 6.4e-02 ms⁻¹, wall time: 1.083 minutes
Iteration: 2080, time: 1.737 hours, Δt: 2.305 seconds, max(|w|) = 7.1e-02 ms⁻¹, wall time: 1.092 minutes
Iteration: 2120, time: 1.763 hours, Δt: 2.357 seconds, max(|w|) = 5.9e-02 ms⁻¹, wall time: 1.101 minutes
Iteration: 2160, time: 1.789 hours, Δt: 2.363 seconds, max(|w|) = 6.3e-02 ms⁻¹, wall time: 1.109 minutes
Iteration: 2200, time: 1.816 hours, Δt: 2.455 seconds, max(|w|) = 6.8e-02 ms⁻¹, wall time: 1.119 minutes
Iteration: 2240, time: 1.842 hours, Δt: 2.376 seconds, max(|w|) = 6.9e-02 ms⁻¹, wall time: 1.127 minutes
Iteration: 2280, time: 1.867 hours, Δt: 2.455 seconds, max(|w|) = 6.3e-02 ms⁻¹, wall time: 1.135 minutes
Iteration: 2320, time: 1.894 hours, Δt: 2.252 seconds, max(|w|) = 6.1e-02 ms⁻¹, wall time: 1.143 minutes
Iteration: 2360, time: 1.920 hours, Δt: 2.501 seconds, max(|w|) = 7.2e-02 ms⁻¹, wall time: 1.151 minutes
Iteration: 2400, time: 1.948 hours, Δt: 2.531 seconds, max(|w|) = 5.7e-02 ms⁻¹, wall time: 1.160 minutes
Iteration: 2440, time: 1.976 hours, Δt: 2.412 seconds, max(|w|) = 5.0e-02 ms⁻¹, wall time: 1.168 minutes
[ Info: Simulation is stopping after running for 1.176 minutes.
[ Info: Simulation time 2 hours equals or exceeds stop time 2 hours.

Turbulence visualization

We animate the data saved in ocean_wind_mixing_and_convection.jld2. We prepare for animating the flow by loading the data into FieldTimeSeries and defining functions for computing colorbar limits.

filepath = filename * ".jld2"

time_series = (w = FieldTimeSeries(filepath, "w"),
               T = FieldTimeSeries(filepath, "T"),
               S = FieldTimeSeries(filepath, "S"),
               νₑ = FieldTimeSeries(filepath, "νₑ"))
(w = 128×1×65×121 FieldTimeSeries{InMemory} located at (Center, Center, Face) of w at ocean_wind_mixing_and_convection.jld2
├── grid: 128×128×64 RectilinearGrid{Float64, Periodic, Periodic, Bounded} on CPU with 3×3×3 halo
├── indices: (:, 64:64, :)
├── time_indexing: Linear()
├── backend: InMemory()
├── path: ocean_wind_mixing_and_convection.jld2
├── name: w
└── data: 134×1×71×121 OffsetArray(::Array{Float64, 4}, -2:131, 64:64, -2:68, 1:121) with eltype Float64 with indices -2:131×64:64×-2:68×1:121
    └── max=0.0514535, min=-0.0558534, mean=2.87973e-5, T = 128×1×64×121 FieldTimeSeries{InMemory} located at (Center, Center, Center) of T at ocean_wind_mixing_and_convection.jld2
├── grid: 128×128×64 RectilinearGrid{Float64, Periodic, Periodic, Bounded} on CPU with 3×3×3 halo
├── indices: (:, 64:64, :)
├── time_indexing: Linear()
├── backend: InMemory()
├── path: ocean_wind_mixing_and_convection.jld2
├── name: T
└── data: 134×1×70×121 OffsetArray(::Array{Float64, 4}, -2:131, 64:64, -2:67, 1:121) with eltype Float64 with indices -2:131×64:64×-2:67×1:121
    └── max=19.9958, min=0.0, mean=18.5883, S = 128×1×64×121 FieldTimeSeries{InMemory} located at (Center, Center, Center) of S at ocean_wind_mixing_and_convection.jld2
├── grid: 128×128×64 RectilinearGrid{Float64, Periodic, Periodic, Bounded} on CPU with 3×3×3 halo
├── indices: (:, 64:64, :)
├── time_indexing: Linear()
├── backend: InMemory()
├── path: ocean_wind_mixing_and_convection.jld2
├── name: S
└── data: 134×1×70×121 OffsetArray(::Array{Float64, 4}, -2:131, 64:64, -2:67, 1:121) with eltype Float64 with indices -2:131×64:64×-2:67×1:121
    └── max=35.0129, min=0.0, mean=33.0007, νₑ = 128×1×64×121 FieldTimeSeries{InMemory} located at (Center, Center, Center) of νₑ at ocean_wind_mixing_and_convection.jld2
├── grid: 128×128×64 RectilinearGrid{Float64, Periodic, Periodic, Bounded} on CPU with 3×3×3 halo
├── indices: (:, 64:64, :)
├── time_indexing: Linear()
├── backend: InMemory()
├── path: ocean_wind_mixing_and_convection.jld2
├── name: νₑ
└── data: 134×1×70×121 OffsetArray(::Array{Float64, 4}, -2:131, 64:64, -2:67, 1:121) with eltype Float64 with indices -2:131×64:64×-2:67×1:121
    └── max=0.0220095, min=0.0, mean=0.000425655)

We start the animation at $t = 10$ minutes since things are pretty boring till then:

times = time_series.w.times
intro = searchsortedfirst(times, 10minutes)
11

We are now ready to animate using Makie. We use Makie's Observable to animate the data. To dive into how Observables work we refer to Makie.jl's Documentation.

n = Observable(intro)

 wₙ = @lift time_series.w[$n]
 Tₙ = @lift time_series.T[$n]
 Sₙ = @lift time_series.S[$n]
νₑₙ = @lift time_series.νₑ[$n]

fig = Figure(size = (1800, 900))

axis_kwargs = (xlabel="x (m)",
               ylabel="z (m)",
               aspect = AxisAspect(grid.Lx/grid.Lz),
               limits = ((0, grid.Lx), (-grid.Lz, 0)))

ax_w  = Axis(fig[2, 1]; title = "Vertical velocity", axis_kwargs...)
ax_T  = Axis(fig[2, 3]; title = "Temperature", axis_kwargs...)
ax_S  = Axis(fig[3, 1]; title = "Salinity", axis_kwargs...)
ax_νₑ = Axis(fig[3, 3]; title = "Eddy viscocity", axis_kwargs...)

title = @lift @sprintf("t = %s", prettytime(times[$n]))

 wlims = (-0.05, 0.05)
 Tlims = (19.7, 19.99)
 Slims = (35, 35.005)
νₑlims = (1e-6, 5e-3)

hm_w = heatmap!(ax_w, wₙ; colormap = :balance, colorrange = wlims)
Colorbar(fig[2, 2], hm_w; label = "m s⁻¹")

hm_T = heatmap!(ax_T, Tₙ; colormap = :thermal, colorrange = Tlims)
Colorbar(fig[2, 4], hm_T; label = "ᵒC")

hm_S = heatmap!(ax_S, Sₙ; colormap = :haline, colorrange = Slims)
Colorbar(fig[3, 2], hm_S; label = "g / kg")

hm_νₑ = heatmap!(ax_νₑ, νₑₙ; colormap = :thermal, colorrange = νₑlims)
Colorbar(fig[3, 4], hm_νₑ; label = "m s⁻²")

fig[1, 1:4] = Label(fig, title, fontsize=24, tellwidth=false)

fig

And now record a movie.

frames = intro:length(times)

@info "Making a motion picture of ocean wind mixing and convection..."

record(fig, filename * ".mp4", frames, framerate=8) do i
    n[] = i
end
[ Info: Making a motion picture of ocean wind mixing and convection...


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