.:twodc:home

Format

 twodc - 2-DC data structure with format

 twodc = REPLICATE({ $                     ; Byte      Description
          FRONT:161UL,                   $ ; 00-03     CONSTANT Y'10100001'
          IMAGE:BYTARR(4096),            $ ; 04-4099   2-D Image Slices
          STTIME:0UL,                    $ ; 4100-4103 Image Start (Seconds from midnight*10000)
          NDTIME:0UL,                    $ ; 4104-4107 Image End (Seconds from midnight*10000)
          STTAS:0U,                      $ ; 4108-4109 Image Start TAS *100
          NDTAS:0U,                      $ ; 4110-4111 Image End TAS *100
          SPARE:0UL,                     $ ; 4112-4115 Space               
          DATE:0UL,                      $ ; 4116-4119 Date (MMDDYY)
          Spare1:0UL,                    $ ; 4120-4123 Total Air Temperature Multiplied by 100 in Kelvin
          Spare2:0UL},                   $ ; 4124-4127 Spare
          4)                               ; 4 element Array

Conversion from Total Air Temperature (TAT) to Static Air Temperature (SAT)

The difference between TAT and SAT is called ram rise (RR) and is caused by compressibility and friction of the air at high velocities.

<math>RRtotal=TAT-SAT</math>

where

<math>RRtotal=V^2/87^2</math>

V is the air speed in knot