Daily precip average

[Michael Timlin]

Since you have 7*365+1 days, I'm assuming you have data that includes
the leap day in 1988.  The calculation you show below does not
account for the extra day in 1988.  You will actually be averaging as
follows:

For t=1, averages 1jan85, 86, 87, 88 with 31dec88, 89, 90, 91.
For t=2, averages 2jan85, 86, 87, 88 with 1jan89, 90, 91.
For t=3, averages 3jan85, 86, 87, 88 with 2jan89, 90, 91.
...
For t=59, averages 28feb85, 86, 87, 88 with 27feb89, 90, 91.
For t=60, averages 1mar85, 86, 87, with 29feb88 and with 28feb89, 90, 91.
For t=61, averages 2mar85, 86, 87, with 1mar88, 89, 90, 91.
For t=62, averages 3mar85, 86, 87, with 2mar88, 89, 90, 91.
For t=63, averages 4mar85, 86, 87, with 3mar88, 89, 90, 91.
...
For t=365, averages 31dec85, 86, 87, with 30dec88, 89, 90, 91.

As far as I know you can't do this within grads unless you omit the
values for 29feb1988.

Mike Timlin
timlin at atmos.uiuc.edu



>Hi all,
>
>I have a file with daily precip for 2556 days for a watershed (1jan1985
>to 31dec1991). What I'm trying to do is a daily precipitation average,
>that is, 1jan average precip (85,86,87,88,89,90,91), 2jan average precip
>and so forth, for an entire year.
>
>So far I have been using these commands:
>
>set x 1
>set y 1
>set t 1 365
>d tloop(ave(aave(ppt,x=1,x=33,y=1,y=31),t+0,t=2556,365))
>
>The display command works fine but I'm not sure I'm doing the right
>calculations. Could someone confirm if I'm on the right track? Or am I
>totally wrong?
>
>Thanks a bunch
>
>Daniel
>
>
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