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Aerosols

ClimaAtmos implements two modes for ozone profiles. These are only relevant for the radiation transfer, and only when RRTMGP is used.

Idealized Ozone Profile

The IdealizedOzone type of ozone uses the idealized_ozone function to compute an idealized ozone profile based on the work of Wing2018. This profile is not time-varying.

The idealized_ozone function returns the ozone concentration in volume mixing ratio (VMR) at a given altitude z.

ClimaAtmos.idealized_ozone — Function
idealized_ozone(z::FT)

Returns idealized ozone volume mixing ratio (VMR) from Wing et al. 2018.

The ozone profile is calculated as a function of altitude z using the following formula:

\[O_3(z) = g_1 p^{g_2} e^{(-p / g_3)}\]

where:

  • O_3(z) is the ozone concentration in volume mixing ratio (VMR) at altitude z.

  • p is the pressure at altitude z calculated using the hydrostatic equation: p = P_0 exp(-z / H_{Earth}), where P_0 is the surface pressure and H_{Earth} is the scale height of the Earth's atmosphere (assumed to be 7000 meters).

  • g_1, g_2, and g_3 are empirical constants.

References

  • Wing, A. A., et al. (2018). Radiative-convective equilibrium model intercomparison project. Geoscientific Model Development, 11(2), 663-690.
source

This function looks like

using CairoMakie
import ClimaAtmos

z = range(0, 60000, length=100)
ozone = ClimaAtmos.idealized_ozone.(z)

lines(ozone, z)
Example block output

Prescribed Ozone Profile

The PrescribedOzone type of ozone uses CMIP6 forcing data to prescribe ozone as read from files. A high-resolution, multi-year file is available in the ozone_concentrations artifact. This file is not small, so you have to obtain independently. Please, refer to ClimaArtifacts for more information. If the file is not found, a low-resolution, single-year version is used. This is not advised for production simulations.

We interpolate the data from file in time every time radiation is called. The interpolation used is the LinerPeriodFilling from ClimaUtilities. This is a linear period-aware interpolation that preserves the annual cycle.

Prescribed CO2 Profile

In addition to ozone, ClimaAtmos can prescribe CO2 concentration using data from Mauna Loa CO2 measurements. This option is enabled with MaunaLoaCO2. Alternatively, FixedCO2 utilizes a constant value that can be prescribed (by default, 397.547 ppm).

More docstrings

ClimaAtmos.PrescribedOzone — Type
PrescribedOzone

Implement a time-varying ozone profile as read from disk.

The CMIP6 forcing dataset is used. For production runs, you should acquire the high-resolution, multi-year ozone_concentrations artifact. If this is not available, a low resolution, single-year version will be used.

Refer to ClimaArtifacts for more information on how to obtain the artifact.

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ClimaAtmos.FixedCO2 — Type
FixedCO2

Implement a static CO2 profile as read from disk.

The data used is the one distributed with RRTMGP.jl.

By default, this is 397.547 parts per million.

This is the volume mixing ratio.

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ClimaAtmos.MaunaLoaCO2 — Type
MuanaLoaCO2

Implement a time-varying CO2 profile as read from disk.

The data from the Mauna Loa CO2 measurements is used. It is a assumed that the concentration is constant.

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