View source for .:twodc:home

==Format==
  *.2dc - 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

  *.cip - Cloud Imaging Probe (CIP) image data stored in the 2-DC data structure.  Format is:
  cip   = REPLICATE({ $                     ; Byte      Description
           FRONT:161UL,                   $ ; 00-03     CONSTANT Y'10100001'
           IMAGE:BYTARR(4096),            $ ; 04-4099   CIP compressed 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

  *.pip - Precipitation Imaging Probe (PIP) image data stored in the 2-DC data structure.  Format is:
  pip   = REPLICATE({ $                     ; Byte      Description
           FRONT:161UL,                   $ ; 00-03     CONSTANT Y'10100001'
           IMAGE:BYTARR(4096),            $ ; 04-4099   PIP compressed 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

Note: The 2-DC image data slices are stored in a 12-bit array while the CIP and PIP image data are compressed binary data that are stored within a 12-byte array.  Therefore a decompression routine is required to extract the CIP and PIP images from this format.

==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