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aerocm.climate_models.ipcc_climate_model

This module contains the IPCC climate model implementation.

IPCCClimateModel

IPCCClimateModel(start_year, end_year, specie_name, specie_inventory, specie_settings, model_settings)

Bases: ClimateModel

Class for the IPCC climate model implementation.

Notes

References: - Myhre et al. (2013). https://doi.org/10.1017/CBO9781107415324.018 - Forster et al. (2021). https://doi.org/10.1017/9781009157896.009

Source code in aerocm/utils/classes.py
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def __init__(
        self,
        start_year: int,
        end_year: int,
        specie_name: str,
        specie_inventory: list | np.ndarray,
        specie_settings: dict,
        model_settings: dict,
):
    """Initialize the climate model with the provided settings.

    Parameters
    ----------
    start_year : int
        Start year of the simulation.
    end_year : int
        End year of the simulation.
    specie_name : str
        Name of the species.
    specie_inventory : list or np.ndarray
        Emission profile for the species.
    specie_settings : dict
        Dictionary containing species settings.
    model_settings : dict
        Dictionary containing model settings.
    """

    # --- Validate parameters ---
    self.validate_model_settings(model_settings)
    self.validate_specie_settings(specie_name, specie_settings)
    self.validate_inventory(start_year, end_year, specie_inventory)

    # --- Store parameters ---
    self.start_year = start_year
    self.end_year = end_year
    self.specie_name = specie_name
    self.specie_inventory = specie_inventory
    self.specie_settings = specie_settings
    self.model_settings = model_settings

run

run(return_df=False)

Run the IPCC climate model with the assigned input data.

Parameters:

Name Type Description Default
return_df bool

If True, returns the results as a pandas DataFrame, by default False.

False

Returns:

Name Type Description
output_data dict

Dictionary containing the results of the LWE climate model.

Source code in aerocm/climate_models/ipcc_climate_model.py
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def run(self, return_df: bool = False) -> dict | pd.DataFrame:
    """Run the IPCC climate model with the assigned input data.

    Parameters
    ----------
    return_df : bool, optional
        If True, returns the results as a pandas DataFrame, by default False.

    Returns
    -------
    output_data : dict
        Dictionary containing the results of the LWE climate model.
    """

    # --- Extract species settings ---
    sensitivity_rf = self.specie_settings.get("sensitivity_rf", None)
    ratio_erf_rf = self.specie_settings["ratio_erf_rf"]
    efficacy_erf = self.specie_settings.get("efficacy_erf", 1.0)
    ch4_loss_per_nox = self.specie_settings.get("ch4_loss_per_nox", 0.0)  # only for NOx - CH4 decrease and induced

    # --- Extract simulation settings ---
    start_year = self.start_year
    end_year = self.end_year
    specie_name = self.specie_name
    specie_inventory = self.specie_inventory
    years = list(range(start_year, end_year + 1))

    # --- Run the IPCC climate model ---
    if specie_name == "CO2":
        equivalent_emissions = (
                specie_inventory / 10 ** 12
        )  # Conversion from kgCO2 to GtCO2

        co2_molar_mass = 44.01 * 1e-3  # [kg/mol]
        air_molar_mass = 28.97e-3  # [kg/mol]
        atmosphere_total_mass = 5.1352e18  # [kg]
        radiative_efficiency = 1.33e-5  # radiative efficiency [W/m^2/ppb] with AR6 value
        A_co2_unit = (
                radiative_efficiency
                * 1e9
                * air_molar_mass
                / (co2_molar_mass * atmosphere_total_mass)
        )  # RF per unit mass increase in atmospheric abundance of CO2 [W/m^2/kg]

        A_co2 = A_co2_unit * specie_inventory
        a = [0.2173, 0.2240, 0.2824, 0.2763]
        tau = [0, 394.4, 36.54, 4.304]

        radiative_forcing_from_year = np.zeros(
            (len(specie_inventory), len(specie_inventory))
        )
        # Radiative forcing induced in year j by the species emitted in year i
        for i in range(0, len(specie_inventory)):
            for j in range(0, len(specie_inventory)):
                if i <= j:
                    radiative_forcing_from_year[i, j] = A_co2[i] * a[0]
                    for k in [1, 2, 3]:
                        radiative_forcing_from_year[i, j] += (
                                A_co2[i] * a[k] * np.exp(-(j - i) / tau[k])
                        )
        radiative_forcing = np.zeros(len(specie_inventory))
        for k in range(0, len(specie_inventory)):
            radiative_forcing[k] = np.sum(radiative_forcing_from_year[:, k])
        effective_radiative_forcing = radiative_forcing * ratio_erf_rf

    else:
        if specie_name == "NOx - CH4 decrease and induced":
            min_year = min(start_year, 1939)
            max_year = max(end_year, 2051)
            tau_reference_year = [min_year, 1940, 1980, 1994, 2004, 2050, max_year]
            tau_reference_values = [11, 11, 10.1, 10, 9.85, 10.25, 10.25]
            tau_function = interp1d(
                tau_reference_year, tau_reference_values, kind="linear"
            )
            years = list(range(start_year, end_year + 1))
            tau = tau_function(years)
            ch4_molar_mass = 16.04e-3  # [kg/mol]
            air_molar_mass = 28.97e-3  # [kg/mol]
            atmosphere_total_mass = 5.1352e18  # [kg]
            radiative_efficiency = 3.454545e-4  # radiative efficiency [W/m^2/ppb] with AR6 value (5.7e-4) without indirect effects
            A_CH4_unit = (
                    radiative_efficiency
                    * 1e9
                    * air_molar_mass
                    / (ch4_molar_mass * atmosphere_total_mass)
            )  # RF per unit mass increase in atmospheric abundance of CH4 [W/m^2/kg]
            A_CH4 = A_CH4_unit * ch4_loss_per_nox * specie_inventory
            f1 = 0.5  # Indirect effect on ozone
            f2 = 0.15  # Indirect effect on stratospheric water
            radiative_forcing_from_year = np.zeros(
                (len(specie_inventory), len(specie_inventory))
            )
            # Radiative forcing induced in year j by the species emitted in year i
            for i in range(0, len(specie_inventory)):
                for j in range(0, len(specie_inventory)):
                    if i <= j:
                        radiative_forcing_from_year[i, j] = (
                                (1 + f1 + f2) * A_CH4[i] * np.exp(-(j - i) / tau[j])
                        )
            radiative_forcing = np.zeros(len(specie_inventory))
            for k in range(0, len(specie_inventory)):
                radiative_forcing[k] = np.sum(radiative_forcing_from_year[:, k])
            effective_radiative_forcing = radiative_forcing * ratio_erf_rf

        else:
            radiative_forcing = sensitivity_rf * specie_inventory
            effective_radiative_forcing = radiative_forcing * ratio_erf_rf

    ## Temperature
    temperature = np.zeros(len(effective_radiative_forcing))
    c = [0.631, 0.429]
    d = [8.4, 409.5]

    if specie_name == "CO2":
        for k in range(0, len(temperature)):
            for ki in range(0, k + 1):
                term = 0
                for j in [0, 1]:
                    term += a[0] * c[j] * (1-np.exp((ki-k)/d[j]))
                    for i in [1,2,3]:
                        term += a[i] * tau[i] * c[j] / (tau[i] - d[j]) * (np.exp((ki - k) / tau[i]) - np.exp((ki - k) / d[j]))
                temperature[k] += A_co2[ki] * term
    elif specie_name == "NOx - CH4 decrease and induced":
        for k in range(0, len(temperature)):
            for ki in range(0, k + 1):
                term = 0
                for j in [0, 1]:
                    term += tau[k] * c[j] / (tau[k] - d[j]) * (np.exp((ki - k) / tau[k]) - np.exp((ki - k) / d[j]))
                temperature[k] += efficacy_erf * (1 + f1 + f2) * A_CH4[ki] * term
    else:
        tau = 1
        for k in range(0, len(temperature)):
            for ki in range(0, k + 1):
                term = 0
                for j in [0,1]:
                    term += tau * c[j] / (tau-d[j]) * (np.exp((ki-k)/tau) - np.exp((ki-k)/d[j]))
                temperature[k] += efficacy_erf * effective_radiative_forcing[ki] * term


    # --- Prepare output ---
    output_data = {
        "radiative_forcing": radiative_forcing,
        "effective_radiative_forcing": effective_radiative_forcing,
        "temperature": temperature
    }

    if return_df:
        output_data = pd.DataFrame(output_data, index=years)
        output_data.index.name = 'Year'

    return output_data