Train the emulator on a set of input ESM temperature and precipitation data.

This function runs all of the steps in the analysis that depend only on the input data. The results are saved in a structure of class fldgen. This structure contains everything the emulator has learned about the model. Therefore, it can be saved and reloaded in future sessions to bypass the analysis step.

trainTP(
  dat,
  tvarname = "tas",
  tlatvar = "lat",
  tlonvar = "lon",
  tvarconvert_fcn = NULL,
  pvarname = "pr",
  platvar = "lat",
  plonvar = "lon",
  pvarconvert_fcn = logPfloor,
  meanfield = pscl_analyze,
  globalAvg_file = NULL,
  record_absolute = FALSE
)

Arguments

dat	A single directory name, or a list of netCDF files. If a directory name is given, all netCDF files in the directory will be used.The pairing of temperature and precipitation netCDF files in the directory relies on the CMIP5 file naming conventions. Other naming conventions are not currently supported.
tvarname	Name of the temperature variable in the temperature netCDF
tlatvar	Name of the latitude coordinate variable in the temperature netCDF files. Normally this is 'lat', but occasionally it will be something different, such as 'lat_2'. Can vary between paired T and P.
tlonvar	Name of the longitude coordinate variable in the temperature netCDF files. Can vary between paired T and P.
tvarconvert_fcn	The function used to transform the T variable prior to training so that it has support on -infinity to infinity. Defaults to NULL, as Temperature is effectively already supported on this range.
pvarname	Name of the precipitation variable in the precipitation netCDF.
platvar	Name of the latitude coordinate variable in the precipitation netCDF files. Normally this is 'lat', but occasionally it will be something different, such as 'lat_2'. Can vary between paired T and P.
plonvar	Name of the longitude coordinate variable in precipitation netCDF files. Can vary between paired T and P.
pvarconvert_fcn	The function used to transform the P variable prior to analyis so that it has support on -infinity to infinity. Defaults to log() as precipitation values cannot be less than 0.
meanfield	Function to compute the mean temperature response field. The default is a linear pattern scaling algorithm.
globalAvg_file	Optional string to use in constructing the name of the file containing global mean temperatures, Tgav. If omitted, calculate Tgav as the mean of the grid cells in each frame. (See "Supplying global mean temperatures" for more information.)
record_absolute	If TRUE, record absolute paths for the input files; otherwise, record relative paths.

Value

A fldgen object.

Details

The steps run by this procedure are read.general, pscl_analyze, and eof_analyze. Additionally, the global mean temperature, global mean precipitation, and the FFT of the EOF decomposition are calculated and stored. For backward compatibility, all of those functions remain part of the public interface.

At present the field generation functions still take as arguments the individual components of the structure; however, in the next version they will expect a fldgen object, which can be constructed manually using fldgen_object.

The names of the input files are recorded in the infiles field of the returned object. This is for the your information only; none of the code here does anything with the recorded filenames. You have the choice of recording either absolute filenames (useful for determining exactly which dataset was used, if you have a lot of similarly named files) or relative filenames (useful if you might distribute a saved model to other users who might not have the same directory structure as you).

Supplying global mean temperatures

In some cases it may be desirable to supply global mean temperatures, rather than calculating them from the grid. For example, the grid may cover only part of the grid, so that the average of the values would not be a true global average. In such cases the true global mean temperatures can be supplied in a separate file.

If this input file is used, it should be a plain text file with one temperature value per line, each line corresponding to one time slice in the corresponding netCDF file containing the grid data. The name of the file will be constructed by adding a suffix (specified in the globalAvg_file argument) to the name of the netCDF file. For example, if the netCDF file is called larry.nc, and the suffix is curly.txt, the name of the global mean temperature file will be larry.nccurly.txt. If multiple netCDF files are passed in, each one will have its own file of global mean temperatures, constructed in the same way.