Data Set Overview
    =================
      Thermal Infrared Multispectral Scanner (TIMS) data were
      collected over geologic features such as volcanic fields,
      playas, dunes, and alluvial fans.  Each image file contains 6
      bands in band-interleaved format, 8 bits per pixel.  Each image
      is accompanied by an auxiliary file which contains the line by
      line temperature values of the references sources as recorded
      by the thermistors during each data take as well as the
      corresponding radiance values (in all six bands) for each
      thermistor as recorded by the scan head.
 
      During the July, 1989, TIMS flights, the reference sources did
      not maintain a constant temperature.  Instead, the temperature
      of the sources appeared to vary periodically (3 degrees on
      average) about a mean temperature (usually the initial preset
      temperature) as tracked by the thermistors.  This temperature
      periodicity was not tracked accurately by the scanner - it was
      more rapid than the scanning period.  Thus, the scanner sampled
      different pieces of the temperature wave during the time of
      data collection.
 
      In addition to this problem, the temperature variation was
      often insufficient to trigger the scanner to record a higher DN
      value, so two or more temperatures (as recorded by the
      thermistors) are often represented by a single DN value.  In
      other words, at no time was the true temperature or the
      corresponding DN value known precisely.  As a result of these
      calibration problems, the TIMS data are presented in values of
      DN only.
 
      Processing Level Id            : 2
      Software Flag                  : N
      Processing Start Time          : 1989-07-18T00:00:00.000
      Processing Stop Time           : 1991-05-28T00:00:00.000
 
 
    Parameters
    ==========
 
      Data Set Parameter 'RADIANCE'
      -----------------------------
        Radiance is the amount of energy per time per projected area
        per steradian.
 
        Data Set Parameter Name        : RADIANCE
        Data Set Parameter Unit        : WATT/(METER*METER)/STERADIAN
        Sampling Parameter Name        : PIXEL
        Sampling Parameter Unit        : METER
        Minimum Sampling Parameter     : N/A
        Maximum Sampling Parameter     : N/A
        Sampling Parameter Resolution  : 56.57
        Sampling Parameter Interval    : 20
        Minimum Available Sampling Int : N/A
        Noise Level                    : UNK
 
 
    Source Instrument Parameters
    ============================
      Instrument Host ID              : C130
      Data Set Parameter Name         : RADIANCE
      Instrument Parameter Name       : RADIANCE
      Important Instrument Parameters : 1
 
 
    Measurement Information
    =======================
 
      Atmospheric Conditions
      ----------------------
        Not Applicable
 
 
      Source
      ------
        Detects thermal energy emitted from the Earth's surface and
        atmosphere.
 
 
      Calibration Standard
      --------------------
        Not Applicable
 
 
      Wavelength Calibration
      ----------------------
        Not Applicable
 
 
    Processing
    ==========
 
      Processing History
      ------------------
        Source Data Set ID          : N/A
        Software                    : UNK
        Product Data Set ID         : C130-E-TIMS-2-EDR-IMAGE-V1.0

Overview
    ========
      The accuracy of brightness temperatures or emissivities
      calculated from TIMS data depends on the accuracy with which
      the brightness temperature of the reference sources can be
      established.  To determine this relationship, laboratory
      measurements involving two different external blackbodies have
      been made.  The first set of measurements indicated that the
      brightness temperature of the internal reference sources agreed
      with the external blackbody to within +/- 1.8 degrees C at all
      internal reference source temperatures checked (24 to 51
      degrees C).  The second set of measurements covering a wider
      range (10 to 55 degrees C) have not yet been fully reduced;
      however, preliminary results do not appear to agree with the
      first set.  It may be that encoded radiance values vary
      somewhat with the temperature of the TIMS itself.
 
      During data acquisition, the TIMS instrument is exposed to the
      atmosphere.  A direct consequence of this experimental set-up
      is an overestimation of the blackbody temperatures, due to the
      presence of condensation on the blackbodies and additional
      radiant cooling of the blackbody surfaces.  This results in an
      underestimation of the radiance of the blackbodies and of the
      ground surface being imaged.  The absolute effects of this
      problem are being presently studied by researchers at the Jet
      Propulsion Laboratory.