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Re: mean or cumul on time axis
Hi Emilie & Ansley,
I just want to add few more points to the discussion.
Suppose we have 6 hrly data. If we want to calculate cumulative sum and
average for a day and if we know which all initial time points(6hrly)
should contribute to a particular destination time point(daily), then
define the daily time axis according to that.
Here is an example :
6hrly time axis & data
yes? define axis/t="01-SEP-1993:18":"04-SEP-1993:06":6/units=hours t6hr
yes? let var = L[GT=t6hr]
yes? list var
VARIABLE : L[GT=T6HR]
SUBSET : 11 points (TIME)
01-SEP-1993 18:00 / 1: 1.00
02-SEP-1993 00:00 / 2: 2.00
02-SEP-1993 06:00 / 3: 3.00
02-SEP-1993 12:00 / 4: 4.00
02-SEP-1993 18:00 / 5: 5.00
03-SEP-1993 00:00 / 6: 6.00
03-SEP-1993 06:00 / 7: 7.00
03-SEP-1993 12:00 / 8: 8.00
03-SEP-1993 18:00 / 9: 9.00
04-SEP-1993 00:00 / 10: 10.00
04-SEP-1993 06:00 / 11: 11.00
yes?
Now which all values will contribute to a daily mean ?
day 1 day2
<-----------------> <-----------------> <------
9 9
| |
|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|
18 0 6 12 18 0 6 12 18 0 6
01/SEP 04/SEP
Say, daily data for 02/SEP/1993 should be defined by data at
02/SEP/1993:00hrs,06hrs,12hrs & 18 hrs then the mean time for
that day is 09hrs. Likewise for 03/SEP/1993 also. That is data at
01/SEP/1993:18hrs & data at 04/SEP/1993:00hrs,06hrs will be skipped
from the calculation. In this case define the "daily" time axis
follows (please note that it is defined only for 09hrs on 02/SEp &
03/SEP)
yes? define axis/t="02-SEP-1993:09":"03-SEP-1993:09":24/units=hours tdly
yes? let vardly = var[gt=tdly@ave]
yes? let varcum = var[gt=tdly@sum]
yes? list varcum, vardly
TIME: 01-SEP-1993 21:00 to 03-SEP-1993 21:00
Column 1: VARCUM is VAR[GT=TDLY@SUM]
Column 2: VARDLY is VAR[GT=TDLY@AVE]
VARCUM VARDLY
02-SEP-1993 09 / 1: 14.00 3.500
03-SEP-1993 09 / 2: 30.00 7.500
yes?
As we can see
daily cumul: data(9hrs) = [data(00hrs)+data(06hrs)+data(12hrs)+data(18hrs)]
------------
02-SEP-1993 09 varcum = [ 2 + 3 + 4 + 5 ] = 14
03-SEP-1993 09 varcum = [ 6 + 7 + 8 + 9 ] = 30
daily mean : data(9hrs) = [data(00hrs)+data(06hrs)+data(12hrs)+data(18hrs)]/4
------------
02-SEP-1993 09 vardly = 14/4 = 3.5
03-SEP-1993 09 cardly = 30/4 = 7.5
Thus, the definition of daily time axis should be accurate if you want to
get the exact mean/sum.
With Regards
Jaison
On Fri, 30 Jul 2004, Emilie Vanvyve wrote:
> Hi Ansley,
>
> Thanks for the documentation! I'll inform you if I encounter again
> strange results with Ferret on Mac.
>
> I read that link and I understand there may be different weights with
> @ave, when grid boxes do not have the same area or when months are not
> considered as equal (weight 1/12 when taking into account their own
> respective length).
> But in my case, as I consider just one grid box and as I try to compute
> a mean or cumul on days from 6 hourly data (so I should not have
> different weight as it may be the case for months), how can I do?
>
> If I try to see "my" weights as in
> http://www.ferret.noaa.gov/Ferret/FAQ/analysis/
> regridding_with_ave.html, it seems to be ok as I get a 0.5 weight for
> 12-hourly average and a 0.25 weight for 24-hourly average (from
> originally 6-hourly data). However, I don't really catch the way Ferret
> puts up with "time-boundary data".
> I'm sorry to insist, but I still do not understand how exactly Ferret
> computed the average in my previous example.
> Here follow two examples. The first one is about weights, the second
> one is my previous example.
>
> Emilie
>
>
> SEE WEIGHTS
>
> work@El Nino ~/Library/Ferret/go/zut > ferret
> NOAA/PMEL TMAP
> FERRET v5.50
> apple-darwin6.3 - 02/08/03
> 30-Jul-04 11:12
>
> ! DEFINE THE VARIABLE 'VAR' (= 1 every 12 hours, 0 else)
>
> yes? define axis/t="1-sep-1993 00:00":"3-SEP-1993 00:00":6/units=hours
> t6h
> yes? let var = if L[gt=t6h] eq 1 or L[gt=t6h] eq 5 or L[gt=t6h] eq 9
> then 1 else 0
> yes? list var
> VARIABLE : IF L[GT=T6H] EQ 1 OR L[GT=T6H] EQ 5 OR
> L[GT=T6H] EQ 9 THEN 1 ELSE 0
> SUBSET : 9 points (TIME)
> 01-SEP-1993 00:00 / 1: 1.000
> 01-SEP-1993 06:00 / 2: 0.000
> 01-SEP-1993 12:00 / 3: 0.000
> 01-SEP-1993 18:00 / 4: 0.000
> 02-SEP-1993 00:00 / 5: 1.000
> 02-SEP-1993 06:00 / 6: 0.000
> 02-SEP-1993 12:00 / 7: 0.000
> 02-SEP-1993 18:00 / 8: 0.000
> 03-SEP-1993 00:00 / 9: 1.000
>
> ! DEFINE NEW TIME AXIS FOR REGRIDDING (12 and 24 hours)
>
> yes? define axis/t="1-sep-1993 00:00":"3-SEP-1993 00:00":12/units=hours
> t12h
> yes? define axis/t="1-sep-1993 00:00":"3-SEP-1993 00:00":24/units=hours
> t24h
>
> ! 12 HOURLY-AVERAGE
>
> yes? list var[gt=t12h@ave]
> VARIABLE : IF L[GT=T6H] EQ 1 OR L[GT=T6H] EQ 5 OR
> L[GT=T6H] EQ 9 THEN 1 ELSE 0
> regrid: 12 hour on T@AVE
> SUBSET : 5 points (TIME)
> 01-SEP-1993 00:00 / 1: 0.6667
> 01-SEP-1993 12:00 / 2: 0.0000
> 02-SEP-1993 00:00 / 3: 0.5000
> 02-SEP-1993 12:00 / 4: 0.0000
> 03-SEP-1993 00:00 / 5: 0.6667
>
> ! 24 HOURLY-AVERAGE
>
> yes? list var[gt=t24h@ave]
> VARIABLE : IF L[GT=T6H] EQ 1 OR L[GT=T6H] EQ 5 OR
> L[GT=T6H] EQ 9 THEN 1 ELSE 0
> regrid: 24 hour on T@AVE
> SUBSET : 3 points (TIME)
> 01-SEP-1993 00 / 1: 0.4000
> 02-SEP-1993 00 / 2: 0.2500
> 03-SEP-1993 00 / 3: 0.4000
>
>
> PREVIOUS EXAMPLE
>
> If the data are:
> 01-SEP-1993 00:00 / 1: 1.00
> 01-SEP-1993 06:00 / 2: 2.00
> 01-SEP-1993 12:00 / 3: 3.00
> 01-SEP-1993 18:00 / 4: 4.00
> 02-SEP-1993 00:00 / 5: 5.00
> 02-SEP-1993 06:00 / 6: 6.00
> 02-SEP-1993 12:00 / 7: 7.00
> 02-SEP-1993 18:00 / 8: 8.00
> 03-SEP-1993 00:00 / 9: 9.00
> 03-SEP-1993 06:00 / 10: 10.00
> 03-SEP-1993 12:00 / 11: 11.00
> 03-SEP-1993 18:00 / 12: 12.00
> 04-SEP-1993 00:00 / 13: 13.00
>
> I would assume to get those numbers for the average:
> (instead of xxxxx shows the results given by Ferret)
>
> t12h@ave
>
> 01-SEP-1993 00:00 / 1: ( 1.00 + 2.00) /2 = 1.50 instead of 1.33
> 01-SEP-1993 12:00 / 2: ( 3.00 + 4.00) /2 = 3.50 3.00
> 02-SEP-1993 00:00 / 3: ( 5.00 + 6.00) /2 = 5.50 5.00
> 02-SEP-1993 12:00 / 4: ( 7.00 + 8.00) /2 = 7.50 7.00
> 03-SEP-1993 00:00 / 5: ( 9.00 + 10.00) /2 = 9.50 9.00
> 03-SEP-1993 12:00 / 6: (11.00 + 12.00) /2 = 11.50 11.00
> 04-SEP-1993 00:00 / 7: (13.00 + ? ) /2 = ? 12.67
>
> t1d@ave
>
> 01-SEP-1993 00:00 / 1: ( 1.00 + 2.00 + 3.00 + 4.00) /4 = 2.50
> instead of 1.80
> 02-SEP-1993 00:00 / 3: ( 5.00 + 6.00 + 7.00 + 8.00) /4 = 6.50
> 5.00
> 03-SEP-1993 00:00 / 5: ( 9.00 + 10.00 + 11.00 + 12.00) /4 = 10.50
> 9.00
> 04-SEP-1993 00:00 / 7: (13.00 + ? ) /4 = ?
> 12.20
>
>
>
>
> Le 29 juil. 2004, ˆ 22:19, Ansley Manke a Žcrit :
>
> > Hi Emile,
> > I'm sending this back to the Users' List so the discussion is
> > available to
> > everyone.
> >
> > I don't know why you were seeing the incorrect results earlier.Ê
> > Please let
> > us know if anything like that happens in the future.Ê When Ferret uses
> > @AVGÊ it looks at the size of the "boxes" along the axis and applies a
> > weighting factor based on the portion of the box on the source axis
> > that
> > overlaps the box on the destination axis.Ê Some of this is discussed
> > in the
> > FAQ,
> > http://www.ferret.noaa.gov/Ferret/FAQ/analysis/regridding_with_ave.html
> >
> > I hope that it has enough explanation to answer your question.Ê I
> > also find
> > that studying the output of commands like these are helpful in
> > understanding
> > what the commands are doing:
> >
> > yes? list t[gt=var], tbox[gt=var], tboxlo[gt=var], tboxhi[gt=var]
> > yes? list t[gt=var12h], tbox[gt=var12h], tboxlo[gt=var12h],
> > tboxhi[gt=var]
> >
> > Emilie Vanvyve wrote:
> >
> > Hi Ansley,
> >
> > Thanks for the rapidity of the answer! That's something I really
> > appreciate with the Ferret users list!!
> >
> > Here are some technical informations: I run Ferret on an
> > Apple-Macintosh platform (Mac OS 10.3.4). It is the 5.50 version that
> > I got from the link on the Ferret website towards Mac OS. Ferret
> > welcomes me with:
> > NOAA/PMEL TMAP
> > FERRET v5.50
> > apple-darwin6.3 - 02/08/03
> > 29-Jul-04 09:29
> >
> > But, I just have tried your script right now on this platform (Mac,
> > Ferret 5.50) and a Linux one (Linux 2.4.3, Ferret 5.51), I have gotten
> > the same numbers as you this time. In a way, that's a good news, but I
> > really do not understand why it has changed since yesterday. I am 100%
> > sure of what I did and sent you. It can not have been confusion with
> > previous variables I could had defined or something like this, as I
> > quitted Ferret and reopened it to get what I sent you.
> >
> > On the other hand, there is still something I do not understand in
> > the results we both get now. The average does not seem to me to be an
> > average and the sum a sum.
> >
> > If the data are as previously:
> > 01-SEP-1993 00:00 / 1: 1.00
> > 01-SEP-1993 06:00 / 2: 2.00
> > 01-SEP-1993 12:00 / 3: 3.00
> > 01-SEP-1993 18:00 / 4: 4.00
> > 02-SEP-1993 00:00 / 5: 5.00
> > 02-SEP-1993 06:00 / 6: 6.00
> > 02-SEP-1993 12:00 / 7: 7.00
> > 02-SEP-1993 18:00 / 8: 8.00
> > 03-SEP-1993 00:00 / 9: 9.00
> > 03-SEP-1993 06:00 / 10: 10.00
> > 03-SEP-1993 12:00 / 11: 11.00
> > 03-SEP-1993 18:00 / 12: 12.00
> > 04-SEP-1993 00:00 / 13: 13.00
> >
> > I would assume to get those numbers for the average and the sum:
> >
> > t12h@ave
> >
> > 01-SEP-1993 00:00 / 1: ( 1.00 + 2.00) /2 = 1.50 instead of 1.33
> > 01-SEP-1993 12:00 / 2: ( 3.00 + 4.00) /2 = 3.50 3.00
> > 02-SEP-1993 00:00 / 3: ( 5.00 + 6.00) /2 = 5.50 5.00
> > 02-SEP-1993 12:00 / 4: ( 7.00 + 8.00) /2 = 7.50 7.00
> > 03-SEP-1993 00:00 / 5: ( 9.00 + 10.00) /2 = 9.50 9.00
> > 03-SEP-1993 12:00 / 6: (11.00 + 12.00) /2 = 11.50 11.00
> > 04-SEP-1993 00:00 / 7: (13.00 + ? ) /2 = ? 12.67
> >
> > t1d@ave
> >
> > 01-SEP-1993 00:00 / 1: ( 1.00 + 2.00 + 3.00 + 4.00) /4 = 2.50 instead
> > of 1.80
> > 02-SEP-1993 00:00 / 3: ( 5.00 + 6.00 + 7.00 + 8.00) /4 = 6.50 5.00
> > 03-SEP-1993 00:00 / 5: ( 9.00 + 10.00 + 11.00 + 12.00) /4 = 10.50 9.00
> > 04-SEP-1993 00:00 / 7: (13.00 + ? ) /4 = ? 12.20
> >
> > t12h@sum
> >
> > 01-SEP-1993 00:00 / 1: ( 1.00 + 2.00) = 3.00 instead of 2.00
> > 01-SEP-1993 12:00 / 2: ( 3.00 + 4.00) = 7.00 6.00
> > 02-SEP-1993 00:00 / 3: ( 5.00 + 6.00) = 11.00 10.00
> > 02-SEP-1993 12:00 / 4: ( 7.00 + 8.00) = 15.00 14.00
> > 03-SEP-1993 00:00 / 5: ( 9.00 + 10.00) = 19.00 18.00
> > 03-SEP-1993 12:00 / 6: (11.00 + 12.00) = 23.00 22.00
> > 04-SEP-1993 00:00 / 7: (13.00 + ? ) = ? 19.00
> >
> > t1d@sum
> >
> > 01-SEP-1993 00:00 / 1: ( 1.00 + 2.00 + 3.00 + 4.00) = 10.00 instead
> > of 4.50
> > 02-SEP-1993 00:00 / 3: ( 5.00 + 6.00 + 7.00 + 8.00) = 26.00 20.00
> > 03-SEP-1993 00:00 / 5: ( 9.00 + 10.00 + 11.00 + 12.00) = 10.50 36.00
> > 04-SEP-1993 00:00 / 7: (13.00 + ? ) = ? 30.50
> >
> > If that's not the purpose of @ave and @sum, how could I then do with
> > Ferret the cumul and mean I have reproduced here above?
> > Hoping it is possible,
> > best regards,
> >
> > Emilie
> >
> >
> > Le 28 juil. 2004, ˆ 19:35, Ansley Manke a Žcrit :
> >
> >
> > Hi Emilie,
> > Thank you for sending this example.Ê What version of Ferret are you
> > running, and on
> > what operating system?Ê The results you are seeing are clearly
> > wrong.Ê When I run
> > your script, I see the following results (first I list the script,
> > then the results.Ê I get these
> > same results on both our Solaris and Linux machines with Ferret
> > version 5.6):
> >
> >
> >
> > ! ----------------- regridtime.jnl -----------------
> > ! Create dummy variable
> > define axis/t="1-sep-1993 00:00":"4-SEP-1993 00:00":6/units=hours t6h
> > let var = L[gt=t6h]
> > list var
> >
> > ! Regrid to 12-hour and to 1-day with @sum
> >
> > define axis/t="01-SEP-1993 00:00":"4-SEP-1993 00:00":12/units=hours
> > t12h
> > let var12h = var[gt=t12h@ave]
> > list var12h
> >
> > define axis/t="01-SEP-1993 00:00":"4-SEP-1993 00:00":1/units=days t1d
> > let var1d = var[gt=t1d@ave]
> > list var1d
> >
> > ! Regrid to 12-hour and to 1-day with @sum
> >
> > define axis/t="01-SEP-1993 00:00":"4-SEP-1993 00:00":12/units=hours
> > t12h
> > let var12h = var[gt=t12h@sum]
> > list var12h
> >
> > define axis/t="01-SEP-1993 00:00":"4-SEP-1993 00:00":1/units=days t1d
> > let var1d = var[gt=t1d@sum]
> > list var1d
> >
> >
> >
> > Here is the output
> >
> >
> >
> > yes? ! ----------------- regridtime.jnl -----------------
> > yes? ! Create dummy variable
> > yes? define axis/t="1-sep-1993 00:00":"4-SEP-1993
> > 00:00":6/units=hours t6h
> > yes? let var = L[gt=t6h]
> > yes? list var
> > ÊÊÊÊÊÊÊÊÊÊÊÊ VARIABLE : L[GT=T6H]
> > ÊÊÊÊÊÊÊÊÊÊÊÊ SUBSETÊÊ : 13 points (TIME)
> > Ê01-SEP-1993 00:00 /Ê 1:ÊÊ 1.00
> > Ê01-SEP-1993 06:00 /Ê 2:ÊÊ 2.00
> > Ê01-SEP-1993 12:00 /Ê 3:ÊÊ 3.00
> > Ê01-SEP-1993 18:00 /Ê 4:ÊÊ 4.00
> > Ê02-SEP-1993 00:00 /Ê 5:ÊÊ 5.00
> > Ê02-SEP-1993 06:00 /Ê 6:ÊÊ 6.00
> > Ê02-SEP-1993 12:00 /Ê 7:ÊÊ 7.00
> > Ê02-SEP-1993 18:00 /Ê 8:ÊÊ 8.00
> > Ê03-SEP-1993 00:00 /Ê 9:ÊÊ 9.00
> > Ê03-SEP-1993 06:00 / 10:Ê 10.00
> > Ê03-SEP-1993 12:00 / 11:Ê 11.00
> > Ê03-SEP-1993 18:00 / 12:Ê 12.00
> > Ê04-SEP-1993 00:00 / 13:Ê 13.00
> >
> > yes? ! Regrid to 12-hour and to 1-day with @sum
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":12/units=hours t12h
> > yes? let var12h = var[gt=t12h@ave]
> > yes? list var12h
> > ÊÊÊÊÊÊÊÊÊÊÊÊ VARIABLE : VAR[GT=T12H@AVE]
> > ÊÊÊÊÊÊÊÊÊÊÊÊ SUBSETÊÊ : 7 points (TIME)
> > Ê01-SEP-1993 00:00 / 1:ÊÊ 1.33
> > Ê01-SEP-1993 12:00 / 2:ÊÊ 3.00
> > Ê02-SEP-1993 00:00 / 3:ÊÊ 5.00
> > Ê02-SEP-1993 12:00 / 4:ÊÊ 7.00
> > Ê03-SEP-1993 00:00 / 5:ÊÊ 9.00
> > Ê03-SEP-1993 12:00 / 6:Ê 11.00
> > Ê04-SEP-1993 00:00 / 7:Ê 12.67
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":1/units=days t1d
> > yes? let var1d = var[gt=t1d@ave]
> > yes? list var1d
> > ÊÊÊÊÊÊÊÊÊÊÊÊ VARIABLE : VAR[GT=T1D@AVE]
> > ÊÊÊÊÊÊÊÊÊÊÊÊ SUBSETÊÊ : 4 points (TIME)
> > Ê01-SEP-1993 00 / 1:ÊÊ 1.80
> > Ê02-SEP-1993 00 / 2:ÊÊ 5.00
> > Ê03-SEP-1993 00 / 3:ÊÊ 9.00
> > Ê04-SEP-1993 00 / 4:Ê 12.20
> >
> > yes? ! Regrid to 12-hour and to 1-day with @sum
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":12/units=hours t12h
> > yes? let var12h = var[gt=t12h@sum]
> > yes? list var12h
> > ÊÊÊÊÊÊÊÊÊÊÊÊ VARIABLE : VAR[GT=T12H@SUM]
> > ÊÊÊÊÊÊÊÊÊÊÊÊ SUBSETÊÊ : 7 points (TIME)
> > Ê01-SEP-1993 00:00 / 1:ÊÊ 2.00
> > Ê01-SEP-1993 12:00 / 2:ÊÊ 6.00
> > Ê02-SEP-1993 00:00 / 3:Ê 10.00
> > Ê02-SEP-1993 12:00 / 4:Ê 14.00
> > Ê03-SEP-1993 00:00 / 5:Ê 18.00
> > Ê03-SEP-1993 12:00 / 6:Ê 22.00
> > Ê04-SEP-1993 00:00 / 7:Ê 19.00
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":1/units=days t1d
> > yes? let var1d = var[gt=t1d@sum]
> > yes? list var1d
> > ÊÊÊÊÊÊÊÊÊÊÊÊ VARIABLE : VAR[GT=T1D@SUM]
> > ÊÊÊÊÊÊÊÊÊÊÊÊ SUBSETÊÊ : 4 points (TIME)
> > Ê01-SEP-1993 00 / 1:ÊÊ 4.50
> > Ê02-SEP-1993 00 / 2:Ê 20.00
> > Ê03-SEP-1993 00 / 3:Ê 36.00
> > Ê04-SEP-1993 00 / 4:Ê 30.50
> >
> > ! -----------------
> >
> >
> >
> > Emilie Vanvyve wrote:
> >
> > Hello!
> >
> > I need some help to regrid data on time. I have 6-hourly
> > precipitation values and I'd like to have the cumul and the mean on 1
> > day. I have tried by defining a new time axis and regridding the data
> > using gt=my_new_time_axis@sum and @ave. Ferret obviously computes
> > something, the time axis of my new variable is correct, but I'm a bit
> > perplex about the results Ferret gives me.
> >
> > Here is an example with a dummy variable.
> >
> > yes? list var
> > SUBSET : 13 points (TIME)
> > 01-SEP-1993 00:00 / 1: 1.00
> > 01-SEP-1993 06:00 / 2: 2.00
> > 01-SEP-1993 12:00 / 3: 3.00
> > 01-SEP-1993 18:00 / 4: 4.00
> > 02-SEP-1993 00:00 / 5: 5.00
> > 02-SEP-1993 06:00 / 6: 6.00
> > 02-SEP-1993 12:00 / 7: 7.00
> > 02-SEP-1993 18:00 / 8: 8.00
> > 03-SEP-1993 00:00 / 9: 9.00
> > 03-SEP-1993 06:00 / 10: 10.00
> > 03-SEP-1993 12:00 / 11: 11.00
> > 03-SEP-1993 18:00 / 12: 12.00
> > 04-SEP-1993 00:00 / 13: 13.00
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":12/units=hours t12h
> > yes? let var12h = var[gt=t12h@ave]
> > yes? list var12h
> > VARIABLE : VAR[GT=T12H@AVE]
> > SUBSET : 7 points (TIME)
> > 01-SEP-1993 00:00 / 1: 1.000
> > 01-SEP-1993 12:00 / 2: 2.000
> > 02-SEP-1993 00:00 / 3: 3.000
> > 02-SEP-1993 12:00 / 4: 4.000
> > 03-SEP-1993 00:00 / 5: 5.000
> > 03-SEP-1993 12:00 / 6: 6.000
> > 04-SEP-1993 00:00 / 7: 7.000
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":1/units=days t1d
> > yes? let var1d = var[gt=t1d@ave]
> > yes? list var1d
> > VARIABLE : VAR[GT=T1D@AVE]
> > SUBSET : 4 points (TIME)
> > 01-SEP-1993 00 / 1: 1.333
> > 02-SEP-1993 00 / 2: 3.000
> > 03-SEP-1993 00 / 3: 5.000
> > 04-SEP-1993 00 / 4: 6.667
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":12/units=hours t12h
> > yes? let var12h = var[gt=t12h@sum]
> > yes? list var12h
> > VARIABLE : VAR[GT=T12H@SUM]
> > SUBSET : 7 points (TIME)
> > 01-SEP-1993 00:00 / 1: 1.000
> > 01-SEP-1993 12:00 / 2: 2.000
> > 02-SEP-1993 00:00 / 3: 3.000
> > 02-SEP-1993 12:00 / 4: 4.000
> > 03-SEP-1993 00:00 / 5: 5.000
> > 03-SEP-1993 12:00 / 6: 6.000
> > 04-SEP-1993 00:00 / 7: 7.000
> >
> > yes? define axis/t="01-SEP-1993 00:00":"4-SEP-1993
> > 00:00":1/units=days t1d
> > yes? let var1d = var[gt=t1d@sum]
> > yes? list var1d
> > VARIABLE : VAR[GT=T1D@SUM]
> > SUBSET : 4 points (TIME)
> > 01-SEP-1993 00 / 1: 2.00
> > 02-SEP-1993 00 / 2: 6.00
> > 03-SEP-1993 00 / 3: 10.00
> > 04-SEP-1993 00 / 4: 10.00
> > yes?
> >
> > Where am I wrong?
> >
> > Thanks for any clue!
> >
> > Emilie
> >
> > ____________________________________________________________
> > Emilie VANVYVE
> > Physicist, PhD student
> >
> > UniversitŽ catholique de Louvain (UCL)
> > Institut d'astronomie et de gŽophysique G. Lema”tre (ASTR)
> > Chemin du Cyclotron, 2
> > 1348 Louvain-la-Neuve (Belgium)
> > Phone : +32-(0)10-473300
> > Fax : +32-(0)10-474722
> > E-mail : vanvyve@astr.ucl.ac.be
> > Web : www.astr.ucl.ac.be
> >
> >
> >
> > ____________________________________________________________
> > Emilie VANVYVE
> > Physicist, PhD student
> >
> > UniversitŽ catholique de Louvain (UCL)
> > Institut d'astronomie et de gŽophysique G. Lema”tre (ASTR)
> > Chemin du Cyclotron, 2
> > 1348 Louvain-la-Neuve (Belgium)
> > Phone : +32-(0)10-473300
> > Fax : +32-(0)10-474722
> > E-mail : vanvyve@astr.ucl.ac.be
> > Web : www.astr.ucl.ac.be
> >
> >
> >
> ____________________________________________________________
> Emilie VANVYVE
> Physicist, PhD student
>
> UniversitŽ catholique de Louvain (UCL)
> Institut d'astronomie et de gŽophysique G. Lema”tre (ASTR)
> Chemin du Cyclotron, 2
> 1348 Louvain-la-Neuve (Belgium)
> Phone : +32-(0)10-473300
> Fax : +32-(0)10-474722
> E-mail : vanvyve@astr.ucl.ac.be
> Web : www.astr.ucl.ac.be
>
--
___________________________________________________
Jaison Kurian
Centre for Atmospheric and Oceanic Sciences
Indian Institute of Science
B A N G A L O R E 560 012
Ph: +91-80-3942505
+91-80-3600450
Fax:+91-80-3600865
___________________________________________________
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