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Wind SWE K0 Quality Flag Guide

The quality flags for each parameter are given as integers 4 bytes long (integer*4). The individual "bits" for each quality value are set
(or cleared) in the analysis code by adding (or subtracting) a power of 2 as follows:

To set the 1st bit, add 1.
To set the 2nd bit, add 2,
To set the 3rd bit, add 4,
To set the 4th bit, add 8, and so on.

To test the state of the 8th "bit" of the quality flag in fortran, for example: 

  if( iand(qual_flag,8) .eq. 8 ) then
    !The quality bit is set!
  end if

Quality flags are set in the analysis program that generates the KP
data.  Previous descriptions of their meaning were out of date.
The flag is the numerical value of bits set as listed below.
numerical flag.  Examples are given at the end of the following list.

c********************************************************************
c   BIT  TO_SET_BIT     MEANING
c********************************************************************
    1    +1         = 3 point parabolic fits to proton peaks were not attempted.
    2    +2         = non-linear least squares fit was not attempted.
    3    +4         = 3 point parabolic fits to proton peaks FAILED.
    4    +8         = non-linear least squares fit FAILED.
                        (Non-linear fit may be reported as good for protons and, at the same time, not good for alphas.)
    5    +16        = Alpha params not valid for reason that the non-linear least squares fit 
                        was done for protons only.  Not enough good energy channels to do simultaneous alpha fit.  
                        (This value applies to iqual_core(5) only.)
    6    +32        = analysis code unable to get good value for spin period.
    7    +64        = SWE instrument in mode 1 - calibration state.
                        key parameters not produced this mode.
                        key parameters only produced in mode 1 - science.
    8   +128        = 3 point fits done for cup 1 only.  Split collector ratio of currents used 
                        to get n/s angle.  Either cup 2 turned off, or cup 2 densities were low 
                        indicating noise associated with vibration.
    9   +256        = fewer than 10 fc_blocks in spectrum. analysis skipped.

   10   +512        = Alpha non-linear fit produced values of thermal speed
                        and density that do not seem reasonable.
   11  +1024        = 3 point parabolic fits to proton peaks done for cup 2 only.  Ratio of 
                        currents on split collectors used to get n/s angle.  Probably Cup 1 is turned off.
   12  +2048        = single width windows.  Delta E over E 6/5% instead of the default 13%
   13  +4096        = tracking mode operation
   14  +8192        = Limited tracking mode scan (Not a full scan)

********************************************************************

Comments:

Non-linear fits are not done for Key Parameters (KPs), but those parameter values are 
excellent and should be used to do science; non-linear fits are available, but they 
have problems which suggest strongly that the KP parameters should be used (see paper 
by Kasper et al., "Physics-based tests to identify the accuracy of solar wind ion
measurements: A case study with the Wind Faraday Cups", J. Geophys. Res., 111, A03105, 
doi:101029/2005JA011442.

Examples (note that all are even numbers because non-linear fits were not attempted):

FLAG    Meaning
----    -------
4098    Tracking mode (4096) full scan  + no non-linear (2)

14338   Limited tracking mode (8192) + Tracking mode (4096)
         + Single-width windows (2048) + no non-linear (2)

14342   As above, but 3-point fit failed (Note fill parameters)

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