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[ferret_users] error in calculating correlation coefficient



Dear ferret users.

I want to calculate temporal correlation between two datasets. Both datasets are area average values with equal number of time steps but ferret is giving error when I tried to compute correlation between the two. My guess is there is inconsistency in unit of time dimension between the dataset which is causing the problem. But how can I overcome this?
==========
Below is my commands and ferret messages:

use HCIyear17.nc, j4pranom2.nc
sh d/f
     currently SET data sets:
    1> ./HCIyear17.nc
 name     title                             I         J         K         L
 HCI      V850ANOM-V200ANOM                1:1       1:1       1:1       1:17
               on grid GTL1 with -1.000000E+34 for missing data
             X=90.2E:91.2E  Y=19.8N:20.8N  Z=849.5:850.5
  time range: 15-SEP-1989 21:00 to 15-SEP-2005 21:00

    2> ./j4pranom2.nc  (default)
 name     title                             I         J         K         L
 J4PRANOM2
          PRECIP[D=3]-J4PRCLM2             ...       ...       ...       1:17
       (X=70E:90E@AV4, Y=6.2N:25N@AV4)
               on grid GPA1 with -1.000000E+34 for missing data
  time range: 30-SEP-1989 00:00 to 30-SEP-2005 00:00

let p=hci[d=1]; let q=j4pranom2[d=2]
go variance
...
list correl
...
 **ERROR: illegal limits: Q is not in the range T=04-JAN-1971 03:22:19-SEP-1971 20:22
          Axis extremes are T=31-MAR-1989 12:00:31-MAR-2006 12:00
  =========

Then I found from the mailing archieve that the one variables can be regridded to the other grid, with a regridding transformation.
I tried that and apparently it worked but upon close inspection I found that during transfermation the values differs from the original and  one value at the edge was flagged as bad so my guess is this will affect the correlation computated.This is what I mean: continuing from above

stat j4pranom2
             PRECIP[D=3]-J4PRCLM2
             X=70E:90E@AV4, Y=6.2N:25N@AV4
             X:  N/A
             Y:  N/A
             Z:  N/A
             TIME: 31-MAR-1989 12:00 to 31-MAR-2006 12:00
             DATA SET: ./j4pranom2.nc
 Total # of data points: 17 (1*1*1*17)
 # flagged as bad  data: 0
 Minimum value: -1.722
 Maximum value: 4.0644
 Mean    value: 0.00030241 (unweighted average)
 Standard deviation: 1.2375

let q=j4pranom2[d=2,gt=p]
stat q
             J4PRANOM2[D=j4pranom2,GT=P]
             X:  N/A
             Y:  N/A
             Z:  N/A
             TIME: 17-MAR-1989 09:00 to 17-MAR-2006 09:00
             DATA SET: N/A
 Total # of data points: 17 (1*1*1*17)
 # flagged as bad  data: 1
 Minimum value: -1.6715
 Maximum value: 3.8625
 Mean    value: -0.0095812 (unweighted average)
 Standard deviation: 1.2196

============

I look forward to your advice.

Best regards,
Jagadish

=====
Below is the ncdump output of the files:

ncdump -h HCIyear17.nc

netcdf HCIyear17 {
dimensions:
        LON = 1 ;
        LAT = 1 ;
        LEV2_2 = 1 ;
        TIME = UNLIMITED ; // (17 currently)
        bnds = 2 ;
variables:
        double LON(LON) ;
                LON:units = "degrees_east" ;
                LON:modulo = 360. ;
                LON:point_spacing = "even" ;
                LON:axis = "X" ;
        double LAT(LAT) ;
                LAT:units = "degrees_north" ;
                LAT:point_spacing = "even" ;
                LAT:axis = "Y" ;
        double LEV2_2(LEV2_2) ;
                LEV2_2:units = "Pa" ;
                LEV2_2:point_spacing = "even" ;
                LEV2_2:axis = "Z" ;
        double TIME(TIME) ;
                TIME:units = "days since 1989-01-01 00:00:00" ;
                TIME:time_origin = "01-JAN-1989 00:00:00" ;
                TIME:axis = "T" ;
                TIME:bounds = "TIME_bnds" ;
        double TIME_bnds(TIME, bnds) ;
        float HCI(TIME, LEV2_2, LAT, LON) ;
                HCI:missing_value = -1.e+34f ;
                HCI:_FillValue = -1.e+34f ;
                HCI:long_name = "V850ANOM-V200ANOM" ;
                HCI:history = "From HCI" ;
// global attributes:
                :history = "FERRET V6.5    5-Aug-11" ;
                :Conventions = "CF-1.0" ;


ncdump -h
j4pranom2.nc

netcdf j4pranom2 {
dimensions:
    TIME = UNLIMITED ; // (17 currently)
    bnds = 2 ;
variables:
    double TIME(TIME) ;
        TIME:units = "hours since 1971-01-01 00:00:00" ;
        TIME:time_origin = "01-JAN-1971 00:00:00" ;
        TIME:axis = "T" ;
        TIME:bounds = "TIME_bnds" ;
    double TIME_bnds(TIME, bnds) ;
    float J4PRANOM2(TIME) ;
        J4PRANOM2:missing_value = -1.e+34f ;
        J4PRANOM2:_FillValue = -1.e+34f ;
        J4PRANOM2:long_name = "PRECIP[D=3]-J4PRCLM2" ;
        J4PRANOM2:long_name_mod = "X=70E:90E@AV4, Y=6.2N:25N@AV4" ;

// global attributes:
        :history = "FERRET V6.5    5-Aug-11" ;
        :Conventions = "CF-1.0" ;
}

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