Table Processing (Formerly Scripting)

For some purposes it is desired to calculate radiometric quantities for a set of geometries (e.g. variation of the elevation angle), wavelengths (e.g. spectra calculation) or atmospheric states (e.g. sensitivity analysis w.r. to aerosol properties). In the former version of McArtim this was the "script feature".

For these cases McArtim can be invoked with the -t command line switch. In that operation mode McArtim will evaluate the file fn_data_table, use settings from that file found in each row and process radiometric quantities accoding to these settings. The format (i.e. the columns) of the fn_data_table file is described by the file fn_table_description. It must have as many rows as there are columns in fn_data_table. In principle all parameters supplied to McArtim can be accessed through an expression

object.parameter
At the moment only the geometry object, atmospheric constituent profiles and the wavelength supplied in simulation.conf have been tested for their correct functionality in the table processing operation mode. There are two more keywords carry and ignore that are needed in most cases.

Example

Suppose that one wants to calculate radiances at a certain wavelength for a set of geometry parameters given at certain times, e.g. the telescope elevation angle the solar zenith angle and the relative solar azimuth angle for a series of time points. The geometries data file could look like

The fn_table_description looks like:
According to the fn_table_description the data file fn_data_table has five columns of which the first and the second (carry) are carried over to the output line. The other opportunity is the ignore keyword by use of which the data in the respective column are simply ignored. In the example above, the last three columns (3, 4 and 5) are the telescope elevation angle and the two relevant solar position angles.

Accessing Atmospheric Constituent Profiles

Gas number densities or particle optical properties can be accessed through the following syntax:


		name.profile[cluster index, parameter index]

It is important to use the name that is passed to the constituent object defintion file in the name parameter. The cluster index selects the cluster, and parameter index will specify the cluster parameter that shall be modified. For gases only 1 is allowed, particle optical parameter indices range from 1(ext.), 2(ssa), 3(g), 4(h) to 5(p) or more depending on which phase function model is used. For example NO2.profile[3,1] for example will access the number density of NO2 in cluster 3 and HG.profile[7,3] accesses the asymmetry parameter of the particle named "HG" in cluster 7.