# Time problem of monthly mean data

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### Max

May 12, 2022, 12:37:44 AM5/12/22
to HYCOM.org Forum
Hi Alan,

Are these monthly mean data below?

I think no. recs should be 30 or 31 but no. recs of these are 61, 9, 26, 23, 28, and 25.

Can you please check if these data have a problem?

Thank you

- Max

### Max

Jun 9, 2022, 4:09:34 AM6/9/22
to HYCOM.org Forum, Max
Don't you know why  no. recs is different in these files?

### Alan Wallcraft

Jun 10, 2022, 10:54:40 AM6/10/22
to HYCOM.org Forum, Max
The mean day of the first 3 records are the min, max, average day.

st-vsm1.navydsrc.hpc.mil 135> head -n 13 53X_archMN.2011_05.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         31   40298.00  0  0.000  -4.9933121E+01   1.1652845E+01
srfhgt   =         31   40329.00  0  0.000  -1.9516382E+01   1.3948812E+01
surflx   =         31   40313.50  0  0.000  -5.8567511E+02   3.4555576E+02
st-vsm1.navydsrc.hpc.mil 136> head -n 13 53X_archMN.2011_06.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         61   40298.00  0  0.000  -4.9525333E+01   1.1496494E+01
srfhgt   =         61   40359.00  0  0.000  -1.9453716E+01   1.3996861E+01
surflx   =         61   40328.50  0  0.000  -5.4944458E+02   4.0910971E+02

So, 53X_archMN.2011_06 is the average of months 5 and 6 instead of the average of month 6 only.

st-vsm1.navydsrc.hpc.mil 141> head -n 13 928_archMN.2017_05.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =          9   42490.00  0  0.000  -5.5614990E+01   1.0263707E+01
srfhgt   =          9   42499.00  0  0.000  -1.9434381E+01   1.4649388E+01
surflx   =          9   42494.50  0  0.000  -6.4700427E+02   4.2935178E+02
st-vsm1.navydsrc.hpc.mil 143> head -n 13 928_archMN.2017_06.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         30   42521.00  0  0.000  -5.4116100E+01   1.1333158E+01
srfhgt   =         30   42551.00  0  0.000  -1.8963694E+01   1.4270756E+01
surflx   =         30   42536.00  0  0.000  -5.1975604E+02   4.9222437E+02

928_archMN.2017_05 is the average of the 1st 9 days of the month.  You might be better off replacing it with the average of 04 and 06.  I don't have access to the original daily means, so I can't recreate the 05 mean.

st-vsm1.navydsrc.hpc.mil 146> head -n 13 930_archMN.2018_01.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         26   42736.00  0  0.000  -5.4221161E+01   1.0937086E+01
srfhgt   =         26   42766.00  0  0.000  -1.8886330E+01   1.4824276E+01
steric   =         26   42751.46  0  0.000  -1.9253153E+01   1.5430040E+01
st-vsm1.navydsrc.hpc.mil 147> head -n 13 930_archMN.2018_02.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         28   42766.00  0  0.000  -5.4764805E+01   1.1061132E+01
srfhgt   =         28   42794.00  0  0.000  -1.8907375E+01   1.4859701E+01
steric   =         28   42780.00  0  0.000  -1.9161093E+01   1.5634953E+01

For 930_archMN.2018_01 the 26 records span 30 days, so this monthly mean is likely good enough.

The first 4 months of 2021 has a few missing days, but the monthly means are likely OK:

st-vsm1.navydsrc.hpc.mil 157> head -n 13 930_archMN.2020_01.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         30   43465.00  0  0.000  -5.8329739E+01   1.2863902E+01
srfhgt   =         30   43496.00  0  0.000  -1.9257404E+01   2.0680132E+01
steric   =         30   43480.27  0  0.000  -1.9444895E+01   2.0270014E+01
st-vsm1.navydsrc.hpc.mil 158> head -n 13 930_archMN.2020_02.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         23   43496.00  0  0.000  -5.8832039E+01   1.2166242E+01
srfhgt   =         23   43520.00  0  0.000  -1.8969286E+01   1.7897949E+01
steric   =         23   43507.93  0  0.000  -1.9555454E+01   1.8675064E+01
st-vsm1.navydsrc.hpc.mil 159> head -n 13 930_archMN.2020_03.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         28   43526.00  0  0.000  -5.8588848E+01   1.2023198E+01
srfhgt   =         28   43556.00  0  0.000  -1.9483227E+01   1.7171019E+01
steric   =         28   43541.86  0  0.000  -1.9607971E+01   1.8599995E+01
st-vsm1.navydsrc.hpc.mil 160> head -n 13 930_archMN.2020_04.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         29   43557.00  0  0.000  -5.7692612E+01   1.0504010E+01
srfhgt   =         29   43586.00  0  0.000  -1.9525816E+01   1.7358118E+01
steric   =         29   43571.50  0  0.000  -1.9535723E+01   1.7724287E+01
st-vsm1.navydsrc.hpc.mil 161> head -n 13 930_archMN.2020_05.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         31   43586.00  0  0.000  -5.7624783E+01   1.0317311E+01
srfhgt   =         31   43617.00  0  0.000  -1.9878511E+01   1.5056312E+01
steric   =         31   43601.50  0  0.000  -1.9584261E+01   1.6352856E+01

Finally, 2021_02 spans 28 days with 25 records which is likely OK:

st-vsm1.navydsrc.hpc.mil 163> head -n 13 930_archMN.2021_02.b | tail -n 4
field         no. recs  mean day  k  dens        min              max
montg1   =         25   43862.00  0  0.000  -5.9888428E+01   1.2668935E+01
srfhgt   =         25   43890.00  0  0.000  -1.9812866E+01   1.7272903E+01
steric   =         25   43875.82  0  0.000  -1.9481983E+01   1.9681286E+01

Alan.