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[ferret_users] Strange error with time-axis - help!



Hi all,

I am getting strange behavior regarding a time axis that I can’t seem to figure out:

I am using Pyferret v7.5 on a Mac OS X El Capitan.

I am computing carbon transports and carbon and volume transport are on slightly different time-axes:
volume_transport_time is 17-Jul-1986:17-Jul-2100
carbon is on 2-Jul-1986:2-Jul-2100

So the first thing I did was assign the carbon data to the desired time-axis using @NRST


!!! Put dissic_ann onto same time axis as vmo
DEFINE AXIS/CALENDAR=NOLEAP/T="17-JUL-1986":"17-JUL-2100":1/UNITS=years tvmo
let dissic_ann_taxis = dissic_ann[gt=tvmo@NRST]

Then later in my script I compute carbon transport like so:

let carbon_transport = volume_transport*dissic_ann_taxis*12.0107*10^-15*31536000

yes? show grid carbon_transport
    GRID GKK1
 name       axis              # pts   start                end                 subset
 RLON      LONGITUDE          360mr   80.5E(-279.5)        79.5E               full
 RLAT      LATITUDE           200 i   81S                  90N                 full
 LEV       DEPTH (m)           50 i-  5                    5316.4              full
 TYEAR     TIME               115 r   17-JUL-1986 12:00    17-JUL-2100 12:00   full



The issue arises when I go to compute the total transport:

let  lv_carbon  = carbon_transport
set region/y=30S/x=55W:20E

let lvi_ATL_hist_carbon   =   lv_carbon[x=@SUM,z=@SUM,l=1:20@ave]
           *** NOTE: Ambiguous coordinates on T axis: VOLUME_TRANSPORT*DISSIC_ANN_TAXIS*12.0107*10^-15*31536000
 **ERROR: inconsistent sizes of data regions: T axis
          DISSIC_ANN_TAXIS has 21 points (L=01:21)
          _expression_ has 20 points (L=01:20)

This error makes no sense to me, how does DISSIC_ANN_TAXIS have 21 points? This is grid of DISSIC_ANN_TAXIS:


yes? show grid DISSIC_ANN_TAXIS

    GRID (G007)

 name       axis              # pts   start                end                 subset

 RLON      LONGITUDE          360mr   80.5E(-279.5)        79.5E               full

 RLAT      LATITUDE           200 i   81S                  90N                 full

 LEV       DEPTH (m)           50 i-  5                    5316.4              full

 TVMO      TIME               115 r   17-JUL-1986 00:00    17-JUL-2100 00:00   full


If I list lv_carbon[x=@SUM,z=@SUM]
I get the correct 20 values:

 JUL-1986 /  1: -0.6929

 JUL-1987 /  2: -0.6835

 JUL-1988 /  3: -0.6320

 JUL-1989 /  4: -0.6169

 JUL-1990 /  5: -0.7557

 JUL-1991 /  6: -0.5893

 JUL-1992 /  7: -0.5602

 JUL-1993 /  8: -0.6603

 JUL-1994 /  9: -0.5901

 JUL-1995 / 10: -0.7569

 JUL-1996 / 11: -0.6533

 JUL-1997 / 12: -0.6598

 JUL-1998 / 13: -0.6744

 JUL-1999 / 14: -0.7347

 JUL-2000 / 15: -0.5964

 JUL-2001 / 16: -0.5854

 JUL-2002 / 17: -0.5836

 JUL-2003 / 18: -0.6827

 JUL-2004 / 19: -0.5843

 JUL-2005 / 20: -0.6224


and then all of a sudden the average function works without the error:

yes? list lv_carbon[x=@SUM,z=@SUM,l=1:20@ave]

             VARIABLE : CARBON_TRANSPORT

             LONGITUDE: 55W to 20E(380) (XZ summed)

             LATITUDE : 30S

             DEPTH (m): 0 to 5500 (XZ summed)

             TIME     : 16-JAN-1986 00:00 to 16-JAN-2006 00:00 (averaged) NOLEAP

         -0.6457

yes? let lvi_ATL_hist_carbon = lv_carbon[x=@SUM,z=@SUM,l=1:20@ave]

yes? list lvi_ATL_hist_carbon

             VARIABLE : LV_CARBON[X=@SUM,Z=@SUM,L=1:20@AVE]

             LONGITUDE: 55W to 20E(380)

             LATITUDE : 30S

             DEPTH (m): 0 to 5500

             TIME     : 16-JAN-1986 00:00 to 16-JAN-2006 00:00 NOLEAP

         -0.6457


Any insight into this strange behavior would be great as it is preventing me from running my script !

Thank you,

Becki

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