SHDOM: Output Formats

The output goes to a number of plain text files (except for the visualization and netcdf output), each containing a header listing the input parameters. The header also lists the number of iterations taken, which for a k-distribution is the total number over the distribution sum. There are seven output types: Any number of ascii files maybe output during a single run.

A single netcdf output file may be specified in addition to, or instead of, the ascii output files. The netcdf file contains all the output types of the specified ascii files. If the ascii files are not desired, then use NONE for each of the ascii file names. The output in the netcdf file is arranged somewhat differently from the ascii files. For all of the output on a grid, X is the fastest moving index, and Z is the slowest. The total downward flux and downward diffuse flux are output, rather than the downward diffuse and direct flux separately, as in the ascii files. Only those output formats allowed with multiple processors are supported in the netcdf output. Specifically, the V, J, and M formats are not supported, nor is the F 2 format, nor any output on the adaptive grid (i.e. F, H, and S outputs are only on the base grid). All of the information in the header of the ascii files is included as global attributes in the netcdf file. The netcdf output requires using the Fortran 90 driver (shdom90.f90). The shdom_netcdf module was written by Robert Pincus (December 2008).

The radiance output computes the radiance at a single vertical level for a regular grid of locations for a series of directions. There are two visualization output modes, both of which make PDS format images. The first one simulates a fixed position camera, while the second simulates a cross track scanning instrument flying on an airplane. For the camera mode the inputs are the position and pointing direction of the camera, the number of pixels vertically and horizontally, and the pixel spacing. For the cross track scanning mode the inputs are the starting and ending aircraft positions, the distance along track beween scans, and the range of scan angles (<0 for left side, > 0 for right side). The PDS image format has a human readable ascii header followed by the pixel values in straight binary format (from left to right and then top to the bottom of the image). The pixel format may be byte (values 0 to 255) or two byte integers (values -32768 to 32767). PDS format byte images may be viewed with "xv" on some Unix systems and an IDL program, pdstojpeg.pro, is provided to convert the PDS images to JPEG format.

There are several ways to output hemispheric flux, including and the top and bottom of the domain, on a regular horizontal grid at any level, or for every grid point. The net flux convergence may be output for each grid point or for a domain averaged vertical profile. The spherical harmonic output is the mean radiance and net flux vector (proportional to the first 4 terms in the spherical harmonic expansion) and for solar problems includes the direct beam contribution. The source function output lists the extinction and source function computed for a specified direction at every grid point. This can be useful for use by another program such as to compute limb radiances in a spherical geometry. The medium properties output lists the (potentially delta-M scaled) extinction, single scattering albedo, asymmetry parameter, and temperature at the grid points, and is useful for making sure the medium was input correctly.

There is a debugging output file format containing GLE graphics commands to draw the grid cells and arrows showing the neighboring cell relationships for an XZ plane. If this is desired, comment in the call to VISUALIZE_CELLS after the solution iteration loop.