TOGA COARE 
DC-8 Aircraft

PRINCIPAL INVESTIGATOR

Andy Heymsfield
NCAR/MMM
PO Box 3000
Boulder, Colorado 80307
(303) 497-8943
fax:  497-8181
heyms1@ncar.ucar.edu


DATA SUMMARY

The extension .fnxx is the flight number.  The files are ASCII and
contain headers.

Flight Number      Date         Start of Data       End of Data
93-01-07          1/17/93         23:10:10           06:37:39
      08          1/19/93         01:43:50           09:02:09
      09          1/25/93         23:27:10           06:34:57
      10          1/31/93         22:09:29           05:30:25
      11          2/4/93          14:43:00           22:22:00
      12          2/6/93          14:35:21           21:37:00
      13          2/8/93          18:27:14           00:18:03
      14          2/10/93         19:01:39           02:47:45
      15          2/17/93         18:56:32           02:08:43
      16          2/20/93         19:15:03           02:53:13
      17          2/22/93         19:13:56           02:12:44
      18          2/23/93         20:10:18           03:26:57


DATA DESCRIPTION

Time(hrmnsc) - UTC time
NCAR Ambient Temp(C) - The calibrated ambient temperature from NCAR's
     temperature probe 102AU1AF, serial number 41716, in degrees Celsius.
     The sensor was post flight calibrated from 40 to -45 degrees C with
     a linear curve fit in the NCAR/RAF Calibration laboratory 
     to + or - 0.1 degrees C.  A recovery factor was determined from 
     aircraft maneuvers that were performed on flight number 18.  The 
     heating effects of the de-icing probe were also corrected for.
     The NASA DADS data mach number and pressure value were used to 
     calculate the NCAR Ambient Temperature.  This value at worst case 
     is + or - 1 degrees Celsius.
NCAR Total Temp(C) - The calibrated total temperature from NCAR's temperature
     probe.  Same comments as above for ambient temp.
NCAR Dew Pt(C) - The calibrated cryogenic dew point temperature from NCAR's
     cryogenic frost point hygrometer unit #1 in degrees Celsius.
     The mirror temperature was pre flight calibrated from -15 to -80 degrees C
     in the NCAR/RAF Calibration laboratory to + or - 0.3 degrees C.  
     The inlet pressure was calibrated to + or - .6 millibars.
     The NASA DADS data pressure value and the NCAR ambient temperature
     were used along with the cryo mirror temperature and cryo inlet pressure
     to calculate the Dew point temperature.  This value should be close 
     to + or - 1.5 degrees C.  An offset of -4.2 degrees C should be 
     corrected for when you use this dew pt data. You might want to contact
     the PI about this parameter to find out the latest information.
NCAR Frost Pt(C) - The calibrated cryogenic frost point temperature from 
     NCAR's cryogenic frost point hygrometer.  Same comments as above for
     dew pt.
Icing Probe(dV/dt)(mV/s) - The change in voltage over change in time of the
     Rosemount 871F ice-accretion probe in millivolts per second.  
     The data was recorded with 5 mV/s resolution and the instrument can 
     bounce with about 10 mV/s of noise when nothing is present so we
     recommend that a value of at least 15 mV/s for a 2 or 3 second time
     period be used as a detection threshold for liquid water.
Lyman Alpha(Volt) - The raw voltage output of the Lyman-alpha sensor.
NCAR Vertical Velocity Calculation(m/s) - The calculated vertical air
     velocity in meters per second.
     The vertical velocity was calculated using a method used in the past by
     ncar.  The method uses such things as coefficient of lift at zero angle
     of attack, the take off weight of the aircraft, the burn rate, the density,
     the true airspeed, etc .  Since the aircraft's weight and burn rate had
     to be estimated (from NASA), the vertical velocities are offset for each
     flight(usually about -2 to -6 m/s).  This offset sometimes changes during
     the flight if our burn rate estimate differs greatly from the actual burn
     rate.  These offsets can be corrected for by simply adding the average
     offset for the appropriate time period.
     This calculation loses accuracy when the plane has a roll of 
     greater than about +-3 degrees, therefore a dummy value of 99999 
     is placed in the data set when that occurs.
     The vertical velocity calculation is also averaged over a 9 second
     period, because of the characteristic response time of the calculations. 
     We have not yet fully analyzed the values, but are confident that
     they give a very good qualitative estimate, and a good quantitative
     estimate of the vertical air velocities.

 
BAD DATA

99999.0000 is put into the data files when no data existed or when the vertical
air velocity calculations went bad because of roll.

The temperature probe had some minors problems on flights 07 and 09.  The
ambient and total temperature values are bad for the following times:
Flight            Times
fn07             231010-231340

fn09             014823-014842
                 015621-015940
                 020417-020516
                 022619-023411
                 031043-031104
                 040221-040249
                 041509-041515
                 042431-042438
                 044934-050636

Also, since the cryogenic dew and frost point calculations used this 
ambient temperature, they will be incorrect during these times.