********************************
                    ***  CASPR REVISION HISTORY  ***
                    ********************************

Version 5.0, ?? ??? 2005:
  Significant changes:
  - Added cloud typing
  - Added tests for polar stratospheric clouds
  Minor changes:
  - Adjusted channel 3A threshold for clear restoration with NDSI
  - Added a channel 1 cloud test (?)
  - Added the capability of more than two surface types in the cloud detection
		    
		    
Version 4.0.3, 23 May 2002:
  Significant changes: none
  Minor changes:
  - Fixed a bug in prewater.pro for the special case of a single user profile
    applied the the entire image.  The 'pw' array was not being properly
    dimensioned.
  - Added the 'congrid2' function (utils.pro) as a result of the 'pw' problem.
  - More single-image cloud mask refinements (cldmask1.pro).
  - Some changes to plotting procedures (plot_hist in particular)
  - Added the "Running CASPR" help topic.
  - Added a check on the range of relative azimuth angle in 'check_avhrr'.

Version 4.0.2, 21 February 2002:
  Significant changes: none
  Minor changes:
  - Adjusted cloud detection thresholds, in both cldmask1.pro and
    cldmaskn.pro.  Changed nighttime thresholds (11-12 and 3.7-11) to get 
    more cloud. Added the ch4-ch5 time test to the daytime time tests.
    We now get better agreement with the literature for Arctic cloud amounts
    (1991) and South Pole radiation.
  - Turned off cloudy sky surface temperature adjustment over snow, so
    it is only done over sea ice.
  - Modified average.pro, adding a keyword for land mask.
  - Fixed a byte swapping bug in 'usrprof.pro' that affects big endian
    computers (e.g., Sun).
  - Fixed an error in documentation in 'profgrid.pro' concerning ozone units.
  - Fixed a potential divide by zero problem in 'interpos' (cldretau.c).

Version 4.0.1, 1 February 2002:
  This could actually be a minor release rather than a bug release, but
  in the process of fixing a few bugs right after the release of v4.0
  we made a few additional changes.
  - cldmask1.pro:
    - Fixed a minor where NDSI was being calculated for all satellites.  It 
      should only be calculated for NOAA-16 and higher.
    - Modified the function for channel 3 reflectance over ocean for large
      solar zenith angles, the net effect being to increase the threshold.
      Changed the *ADD weights so that the adjustment isn't made over ocean.
    - Added more thresholds to the threshold adjustment (threshadj) section.
  - cldmaskn.pro:
    - Made some of the time and final thresholds dependent upon the 
      surface type.
    - Added the 'pixsize' keyword to the cloudmask_1 calls in cldmaskn.pro.
  - Added a simple relabelling of SNOW to LAND in surftypes.pro is SNOW
    is relatively dark.
  - Added a sixth array input to 'rdpix' in 'rdpixplus.pro'.
  - Fixed and expanded the test 'run.pro' files.

Version 4.0, 18 January 2002:
  Significant changes and new features:
  - Added surface shortwave and longwave cloud forcing variables (internal
    and output).
  - Added more NOAA-15 and -16 capabilities: 
    * surface temperature coefficients for NOAA-16
    * cloud masking with channels 3A and 3B on NOAA-16
  - Updated FluxNet to v4.0
  - Removed the requirement that radiative flux calculations require profiles.
    This was possible because FluxNet v4.0 was designed to use cloud temperature
    rather than cloud pressure.  Profiles are now used only for cloud pressure
    and precipitable water (not required for PW though).
  - Made low sun cloud optical depth retrievals more restrictive, where IR 
    retrievals must have a solution.  Questionable particle size/optical depth 
    retrievals are now set to missing.  So there will be fewer retrievals,
    and hence radiative fluxes, but those that are done should be of higher
    quality.  No data is better than bad data!
  - Rewrote the procedure to calculate cloud water path.  However, this 
    parameter is still not automatically calculated.
  - Modified the cloud masking procedures.  Added the cold cloud over the 
    ocean test, the cold cloud surface temperature test, and the clear 
    (restorative) tests to 'cloudmask_1'.
  - Added the 'full_landmask' keyword, which permits the input of a fully
    defined land mask and avoids the refining procedure.  The refining 
    procedure ('surftypes') was modified to allow for an input mask containing
    SNOW, ICE, and/or OCEAN as well as LAND and NOTLAND, but without the
    mask being considered as "complete".
  - A different surface type mask (land mask) can now be supplied for 
    each image when multiple images are being processed in a time series.
    ***The 'multiple' keyword was changed to 'multiimage' and the 'multiland'
    keyword was added.
  - Rewrote the clear sky compositing, allowing for an input clear sky image
    (even for single image processing), and providing for a more realistic
    n-day composite when processing multiple files (whether a time series or 
    not).  Added the 'clear_composite' keyword.
  - Revised, as part of the clear compositing rewrite, the clear sky statistics
    procedures in 'cloudmask_n'.
  - Added the capability of using a surface temperature estimate in single
    image cloud detection via the 'tsurfest' keyword to caspr.
  - Revised the daytime part of the cloud phase retrieval, eliminating the
    surface dependence (it was an artifact of Streamer v2.5 anyway), and 
    allowing for channel 3A on NOAA-16.
  - Updated the cloud optical depth lookup tables with results from 
    Streamer v3.0.
  - Removed the dependence of aerosol optical depth input on location, which
    wasn't used anyway.
  - Plotting changes: 
    Improved and generalized the image display procedure, renaming it
    to 'plot_image'.  Eliminated the 'plot_cmask' and 'plot_satimage'
    procedures because 'plot_image' can be used instead.  Replaced the gif 
    output option with jpeg because the gif format isn't supported in IDL 
    versions 5.4 and later.  Added the 'degreesC' keyword.
  - Added keywords to allow for lat/lon and land mask directories to be 
    specified.
  - Added netCDF input/output procedures
  - Added procedures to extract values along a line of latitude or longitude
  - Removed the calibration (channels 1 and 2) procedure.  It was rarely,
    if ever, used and therefore not worth maintaining.
    IMPORTANT: The 'calib' and 'are_counts' keywords are no longer available.

  Minor changes:
  - Updated the extinction coefficients in 'cloudext' (cldtemp.pro) with
    values from Streamer v3.0; fixed an error in the IR coefficients for
    water cloud, which used 10 microns rather than 11.
  - Changed the snow-free land emissivities in 'surftemp.c' to those
    of grass.
  - Updated Planck constants according to NESDIS recommendation.
  - Revised the procedures 'normalize12' and 'esdist_correct' to operate on
    a single image (so they're more general).
  - Revised the procedure 'ch3reflectance' to simply copy channel 3A on
    NOAA-16.
  - Added traps for floating point errors (NANs, divide by 0).  Need to
    track these down some day.  For now, bad pixels are set to MISSING.
  - Revised the *.sizes output file contents and added the CASPR version number.
  - Changed the warning strategy for 'cloudpress' so that only one warning is
    issued if temperatures are not in the profile.
  - Fixed bug in writing of center profile to *.params files
  - Changed the map projection in 'plot_satimage' from stereographic to 
    lambert
  - Revised the online help
  - Fixed an insignificant bug in 'fill_clear'
  - Fixed a minor bug in 'surftemp_cloudy' dealing with a data type that
    would have caused a fatal error message.

Version 3.2.4, Sept 7, 2001:
  - Fixed bug in 'fill_clear' involving the dimensions for land and ocean
  - Increased the RANGE value (from 2 to 4) in 'fill_clear'

Version 3.2.3, June 8, 2001:
  - Fixed bug in the tour that resulted from undefined "FALSE" in wplot.

Version 3.2.2, May 2, 2001:
  - Fixed bug in time series cloud masking (procedure 'clear_pairs') where
    the variable ZC was being incorrectly interpolated.

Version 3.2.1, Apr 18 2001:
  - Changed the cloud sky surface temperature procedures so that the only
    operate on sea ice, as the procedures were developed with data from
    SHEBA.
  - Added a procedure to calculate monthly means of *.params files in a
    time series.
  - Adjusted the time series cloud detection thresholds.

Version 3.2, 10 Feb 2001:
  - *This version has different expectations about the form of profile and 
    ozone data that the user provides and is not compatible with previous 
    versions in that regard.  See the procedures in 'usrprof.pro' for details.
  - Significant revisions to the single-image and time series cloud
    detection procedures
  - Allows for a variable number of profile levels at each grid point
  - Allows for a grid of total column ozone 
  - Allows for a "complete" surface mask (all surface types: LAND, OCEAN, ICE,
    and SNOW) to be input
  - Some changes to the display procedures: rewrote 'plot_resimage' and 
    removed the contouring routines as the spatial structure in individual 
    images tend to be too variable for contouring.
  - Replaced test images with data from the AVHRR Polar Pathfinder project
  - Added the 'profile_dir' keyword to 'caspr'.
  - Fixed a logic problem in 'fluxnet.c'.  Not a bug, just something 
    unintended.
  - Added the 'percentile' function for use in 'fill_clear' and in display
    routine.
  - Other minor changes

Version 3.1.2, 12 May 2000:
  - Improved cloud masking over Antarctica during low sun times
  - added the 'rethresh' keyword to 'cloudmask_1' and 'caspr'
  - added the 'nosurf' keyword to 'fill_clear'
  - fixed a minor bug in 'wcaspr.pro' (check_settings)
  - fixed a bug in 'cloudpress' concerning out-of-range temperatures
  - added 'colortable_tvlct' and modified 'plot_resimage accordingly'

Version 3.1.1, 8 Mar 2000:
  - Fixed bug in 'cldmask1.pro' with out of range temps in
    the CCT table
  - modified 'declare_results' so only those arrays that are needed are 
    created (to save memory).

Version 3.1, 11 Feb 2000:
  - Redesigned the display output (simplified) so all plots
    go to separate windows
  - modified and enhanced 'wplot' accordingly
  - reworked 'plot_resimage' to improve color bar and plot lat/lon grid 
    and continents
  - added 'write_subset_results' procedure 
  - fixed a minor bug in 'write_subset'
  - fixed byte swapping bug in 'read_results_image'
  - revised single image cloud masking at night to use channels 4 & 5 
    tests and added additional steps to daytime analyses to get some missed 
    cirrus
  - improved the clear sky filling procedure 'fill_clear'
  - added a crude clear sky compositing procedure in 'retrieve' to help out 
    in very cloudy situations
  - renamed 'cloudtoptemp' to 'cloudtemp', 'cloudtoppress' to 
   'cloudpress', and 'plot_image' to 'plot_satimage'
  - updated the calibration coefficients and central wavenumbers and added 
    NOAA 14, added surface temperature coefficients and calibration of 
    channels 1, 2, and 3 (1.6 um) for NOAA 15, though other aspects of this
    satellite are NOT implemented
  - added a monthly means procedure.

Version 3.01, 29 Oct 1999:
  - Fixed bug in averaging of cloud phase for subregions.

Version 3.0, 27 Oct 1999:
  - Recomputed many of the surface albedo coefficients
  - replaced the anisotropic reflectance correction procedure
  - added low sun angle thresholds in cloud optical depth retrieval
  - added missing value checks to for FluxNet
  - fixed bug in averaging of cloud phase.

Version 3.0b, 10 Sep 1999:
  - Beta test.  Redesigned surface albedo retrieval
  - upgraded FluxNet to version 3.0 and added TOA fluxes
  - added cloudy sky surface temperature
  - changed the time series plot axis labels to mm-dd format
  - fixed a couple problems in 'validate.pro'
  - added median option to 'get_stats'.

------------------------------------------------------------------------------

Version 2.5.2, 16 Apr 1999:
  - Changed 'cloudtoppress' so the tropopause doesn't have
    to be in the profile, and so the higher pressure (lower
    altitude) solution will be chosen when two exist with an inversion
  - fixed bug in computing cloud temperature and pressure when optical 
    depth isn't computed 
  - added cloud amount to means output file
  - changed display to accomodate cloud amount in time series.

Version 2.5.1, 14 Apr 1999:
  - Fixed minor bug in 'fluxnet.pro', where 'cldwc' was
    only being reset for scalar values (would have crashed).

Version 2.5, 6 Apr 1999:
  - Added computation of precipitable water from profiles
  - fixed major problem with FluxNet (that WC isn't really variable)
  - added low temperature cutoff for channel 3 in phase algorithm
  - set the display window number to a constant (for time series problem)
  - fixed times series plot bug.

Version 2.4.1, 16 Mar 1999:
  - Added the 'pixsize' keyword to 'cloudmask_1'
  - switched to Fu & Liou ice cloud parameterization
  - recalibrated test images.

Version 2.4, 25 Feb 1999:
  - Revised the cloud detection algorithms (thresholds and clear
    sky composites)
  - changed 'clrstats.c' (add median, eliminate standard deviation)
  - modified 'fillclr.pro'
  - changed re/tau interpolation for daytime water clouds in the 
    shortwave
  - modified 'nfile_area_results' allowing for multiple lat/lons
  - added 'rdpix_results', modified 'rdpix' for file output
  - eliminated the 'diff45' variable.

Version 2.3.1, 29 Jan 1999:
  - Revised the optical depth/effective radius lookup tables
    to include smaller ice crystals and larger water droplets
  - bug fix in 'wplot.pro' 
  - made a few minor modifications to the display procedures.

Version 2.3, 1 Jan 1999:
  - Changed the cloud particle phase algorithm
  - eliminated the debug keyword (it's still here and there in the 
    code for potential future use)
  - modified some utilities
  - fixed a minor bugs in 'cldmaskn.pro'.

Version 2.2.3, 8 Dec 1998:
  - Modified 'wplot' so it can plot data in memory
  - fixed display colors for plots with color bar
  - fixed 'create_directory' (potential problem with 'spawn')
  - fixed a bug in 'fill_clear'
  - fixed a problem with data types in 'cldretau.c' on SGIs.

Version 2.2.2, 4 Nov 1998:
  - Added "Internal Variables" to on-line help
  - added the 'LAND' and 'OCEAN' possibilities for 'landfln'
  - a few corrections to User's Guide.

Version 2.2.1 ,29 Oct 1998:
  - Added tour
  - minor manual revisions.

Version 2.2,27 Aug 1998:
  - Fixed a few more bugs (`readarg'
  - trapped 0 tau problem

Version 2.2B3, 15 Aug 1998:
  - Adjusted cloud mask thresholds
  - fixed a few bugs in cloudtemp

Version 2.2B2, 1 Aug 1998:
  - Fixed miscellaneous bugs
  - refined optical depth tables
  - made help release the command line.

Version 2.2B, 5 Jul 1998:
  - Added Earth-Sun distance correction
  - added type checking on IDL-C calls
  - improved cloud masking (single-image and time series)
  - rewrote optical depth/effective radius retrieval. 

Version 2.15, 11 Feb 1998:
  - Fixed incorrect scaling in FluxNet and misc. minor bugs.

Version 2.14, 2 Oct 1997:
  - Changed the input longitude range from 0-360 to 0 to +-180.

Version 2.1B, 20 Aug 1997:
  - Redesigned neural networks to do only cloud optical depth and particle 
    effective radius, and went back to original cloud temperature algorithm.  
  - Cleaned up the display procedures.

Version 2.0B, 4 Aug 1997:
  - Recoded many procedures to operate on arrays, some procedures are now 
    in C
  - replaced the cloud tau, Re, Tc algorithm
  - eliminated the option to compute fluxes with Streamer
  - eliminated internal mean profiles
  - reduced the number of parameter categories, removed subsampling from caspr.

-------------------------------------------------------------------------------

Version 1.11, 1 Aug 1996:
  - Implemented no_warn
  - fixed minor bugs.

Version 1.1, 25 Jul 1996:
  - Replaced parameterized flux scheme with FluxNet.

Version 1.07, 9 Jul 1996:
  - Modified optical depth retrieval (again).

Version 1.06, 30 Jun 1996:
  - Modified the cloud particle phase retrieval.

Version 1.05, 10 Jun 1996:
  - Modified the cloud optical depth thermal data.

Version 1.04, 21 May 1996:
  - Added the debug option
  - modified optical depth retrieval.

Version 1.03, 24 Apr 1996:
  - Added the rdpix_results procedure
  - modified cloud mask.

Version 1.02, 5 Mar 1996:
  - Added snow-free land surface temperature algorithm.

Version 1.0, 1 Jan 1996:
  - Minor changes
  - much debugging.

Version 1.0B, 1 Sep 1995:
  - Eliminated the cloud fraction array.

Version 1.0A, 26 Jun 1995:
  - First release.

==============================================================================

A = alpha test
B = beta test