forcing¶

class lowEBMs.Packages.Functions.forcing[source]¶

Bases: object

Class defining radiative forcing terms

Radiative forcing essentially can be comprehended as manipulation of the solar insolation which defines the amount of energy available in the system. This class defines terms which change the amount of energy in the system which can be derived from properties of the system (e.g. atmospheric CO2-concentrations). One has to be cautious when operating with these forcing because they are only used to mimic a radiative forcing detached from the systems propagation and therefore don’t represent interactions of the property which causes the forcing (e.g. the carbon cycle is not considered, only measured or projected trends).

`random`	The random forcing mimics randomly occuring radiative forcing events.
`predefined`	The predefined forcing imports data containing external radiative forcings.
`co2_myhre`	The co2_myhre forcing calculates a radiative forcing from imported atmospheric CO2 conenctration data.

lowEBMs.Packages.Functions.forcing.random(self, funcparam)¶

The random forcing mimics randomly occuring radiative forcing events.

The random forcing is mainly used to mimic volcanic eruptions which are based on the idea that dust clouds, appearing after volcanic eruptions, affect the radiative balance. The consequence of an eruption is a negative radiative forcing over a specific time which generally causes a decrease in temperature, depending on the time and strentgh the forcing acts.

With this module such events are randomly generated. The parameters which have to be provided will determine a rough guess of frequency, strength and length of the events and many more. By setting a time of start and stop, this can be used to turn on/off the random radiative forcing for specifc times.

Function-call arguments

Parameters:	funcparams (dict) – forcingnumber the number of the radiative forcing term (relevant if multiple forcings are used) type: int unit: - value: 0, 1,… start: The time when the forcing starts type: float unit: depending on timeunit value: any stop: The time when the forcing stops type: float unit: depending on timeunit value: any steps: The amount of steps (timeresolution) between start and stop type: int unit: - value: any (preferably the same as `builtins.stepsize_of_integration`) timeunit: The unit of time for the forcing type: string unit: - value: ‘minute’, ‘hour’, ‘day’, ‘week’, ‘month’, ‘year’ (if none, seconds are used) strength: The maximal radiative forcing which can be randomly generated type: float unit: - value: any frequency: A classification how often an event occurs. Creates a window of frequency, from a minimal duration between two events towards a maximal from which the duration to the next event is randomly chosen. type: string unit: - value: options ’common’: the next event is in the following 0-4 steps/total_steps ’intermediate’: the next event is in the following 4-12 steps/total_steps ’rare’: the next event is in the following 12-30 steps/total_steps ’superrare’: the next event is in the following 30-60 steps/total_steps behaviour: The behaviour/shape of the radiative forcing type: string unit: - value: options ’step’: radiative forcing acts as stepfunction with width of one step defined by lifetime ’exponential’: radiative forcing acts exponentially with a halflife defined by lifetimes lifetime: The length on event appears (coupled to behaviour) type: float unit: depending on timeunit value: any seed: Indicates whether the random numbers are generated from a specific seed (for comparison) type: int unit: - value: any (if None, every call is random) sign: The sign of the resulting radiative forcing type: string unit: - value: ‘negative’, ‘positive’
Returns:	A randomly generated radiative forcing
Return type:	float

lowEBMs.Packages.Functions.forcing.predefined(self, funcparam)¶

The predefined forcing imports data containing external radiative forcings.

This module imports radiative forcing data given as change in energy (\(Watt \cdot meter^{-2}\)) and applies it to the model run.

Function-call arguments

Parameters:	funcparams (dict) – forcingnumber the number of the radiative forcing term (relevant if multiple forcings are used) type: int unit: - value: 0, 1,… datapath: The path to the file (give full path or relative path!) type: string unit: - value: example: ‘/insert/path/to/file’ name: The name of the file which is used type: string unit: - value: example: ‘datafile.txt’ delimiter: How the data is delimited in the file type: string unit: - value: example: ‘,’ header: The number of header rows to exclude type: int unit: - value: any col_time: The column where the time is stored type: int unit: - value: any col_forcing: The column where the forcing in stored type: int unit: - value: any timeunit: The unit of time which is used in the file to convert it to seconds type: string unit: - value: ‘minute’, ‘hour’, ‘day’, ‘week’, ‘month’, ‘year’ (if none, seconds are used) BP: If the time is given as “Before present” type: boolean unit: - value: True / False time_start: The time of the first entry (or the time when is should be started to apply it) type: float unit: depending timeunit value: any k: Scaling factor type: float unit: - value: any
Returns:	The radiative forcing for a specific time imported from a data file
Return type:	float

lowEBMs.Packages.Functions.forcing.co2_myhre(self, funcparam)¶

The co2_myhre forcing calculates a radiative forcing from imported atmospheric CO2 conenctration data.

This module imports atmospheric CO2 concentrations from a data file and converts them to a change in energy \(F_{CO2}\) (\(W/m^2\)) after Myhre (1998):

\[F_{CO2}= A\cdot ln(C / C_0)\]

With the atmospheric CO2 concentration \(C\) (\(ppmv\)), the preindustrial atmospheric CO2 concentration \(C_0\) and an empricial constant A (\(5.35\;W/m^2\)).

Function-call arguments

Parameters:	funcparams (dict) – A The empirical constant A type: float unit: \(Watt \cdot meter^{-2}\) value: 5.35 C_0: The preindustrial atmospheric CO2 concentration type: float unit: \(ppmv\) value: 280 C02_base: The CO2 concentration to use before the forcing starts and after it ends type: float unit: \(ppmv\) value: any datapath: The path to the file (give full path or relative path!) type: string unit: - value: example: ‘/insert/path/to/file’ name: The name of the file which is used type: string unit: - value: example: ‘datafile.txt’ delimiter: How the data is delimited in the file type: string unit: - value: example: ‘,’ header: The number of header rows to exclude type: int unit: - value: any footer: The number of footer rows to exclude type: int unit: - value: any col_time: The column where the time is stored type: int unit: - value: any col_conc: The column where the concentration in stored type: int unit: - value: any timeunit: The unit of time which is used in the file to convert it to seconds type: string unit: - value: ‘minute’, ‘hour’, ‘day’, ‘week’, ‘month’, ‘year’ (if none, seconds are used) BP: If the time is given as “Before present” type: boolean unit: - value: True / False time_start: The time of the first entry (or the time when is should be started to apply it) type: float unit: depending timeunit value: any
Returns:	The radiative forcing for a specific time calculated from atmospheric CO2-concentrations imported from a data file
Return type:	float