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Tab::Time dependent input

Last modified by Xwiki VePa on 2025/01/08 07:07

Variables

This is where (most) time dependent input variables is defined. We define the model so that only those variables that are used as input in the model are considered in the setting file. There are couple of options or defining the variables and their values. For example, lets consider O3, ozone. If we are using the ozone concentrations as input, we have the following possibilities:

  • we set it to constant
  • we send in time series of measurements
  • we have measurements but we want to multiply, add or subtract them with a constant
  • we want to use some hypothetical time series. 
  • link the variable with another variable

All of these can be done here. The first thing we need to do is to select O3 from the right hand list "Available input variables", and press the button under "Move to selected". Then,

For a variable:
  • to set it to constant: The default value for any variable here is 0, so setting O3 to constant is done by setting "Shift" to the value. Also define the units! In the figure below this input method is used for CH4.
  • to send in time series of measurements: The variables marked in light blue will be read from the ENV input. In that file time series of O3 is on column number "x" (first column being 1). Insert the column number x to Column. Here you can use the tool Print Input headers with column numbers. In the figure below this input method is used for most variables, for instance REL_HUMIDITY.
  • we have measurements but we want to multiply, add or subtract them with a constant: use Shift or Multi to add, subtract or multiply the measurements read from Column. In the figure below this input method is used for APINENE.
  • to use some hypothetical time series: Use Parametric input (see below). In the figure below this input method is used for ION_PROD_RATE.
  • to link the variable with another variable: Insert the variable name exactly in Column. You can still use Shift and Multi. In the figure below this input method is used for DMA.


The figure shows the full list of time dependent variables for one example simulation:

Variables.png

Mark, mark all, invert

These mark the variables in the left hand side table, after which they can be deleted from the input list (for this particular configuration).

Select fixed from chemistry

The chemistry schemes can be defined so that the precursors are set as FIXVAR (in KPP lingo). These are compounds that generally should be given some values from outside of the model. By pressing Select fixed from chemistry, the tool will search the current chemistry scheme, if there are any fixed variables, they will be selected from the right hand side panel, after which you can press Move to selected and configure the input.

Load fixed from subset_mass

This tool is similar to the previous, but it will pick the precursors from the MCM produced subset_mass text file, if you have downloaded and saved the file when downloading the chemistry scheme from MCM. Click the tool and point it to the file, then, if variables were found, you can press Move to selected and configure the input.

Filter

Selects the Available input variables based on the text in the Filter. Use . (dot) after the text to filter with full word, e.g. OH. will select "OH" and not "HCOOH".

Parametric input

Here you can give a time dependant "curve" for any time dependent input variable. The function is based on a gaussian bell curve, spiced with a sine function in the exponent. Set the minimum and maximum, and adjust the sliders until you get a suitable profile. You can change the scale of the sliders if it helps to fit the curve better to your chosen timespan. When you are happy to save, select one of the variables from the right hand side panel and press Save to selected. By pressing Load selected, you load the current saved parameters of that variable. You can plot another variable sing Plot 2nd. Whenever you press Save to selected, the variable will become highlighted on the previous tab, to mark that you are overriding any Column, Multi or Shift input with parametric input. If you select "No" to the Use PM in the previous tab, the parameters are still saved with the variable and so the parametric input can be toggled on or off.