| Re: NCEP Reanalysis Temperature Data Problem [message #56513 is a reply to message #56512] |
Thu, 25 October 2007 10:38   |
ben.bighair
Messages: 221
Registered: April 2007
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Senior Member |
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On Oct 25, 12:56 pm, David Fanning <da...@dfanning.com> wrote:
> Folks,
>
> I am looking at some monthly NCEP Temperature Data, stored in a
> NetCDF file:
>
> http://www.cdc.noaa.gov/dtat.ncep.reanalysis.pressure.html
>
> I have no problem reading the data file, but the time data,
> which is suppose to be monthly from 1 Jan 1948 to present,
> has a min and max values of 17067072 and 17590104. These looks like
> Julian numbers to me, except they are off by several orders
> of magnitude from anything that makes sense to me!!
>
> IDL> Caldat, 17067072, m, d, y
> IDL> Print, m, d, y
> 12 15 42015
>
> These numbers are even several orders of magnitude bigger
> than the number of SECONDS since 1948. :-(
>
> Does anyone have any experience with this data set and
> have some idea of how I can get these values into something
> that makes sense?
>
Hi David,
While it is hard to figure out the benchmark date - the difference in
the two might be close to the number of hours between 1948 and 2007.
Perhaps it's wishful thinking, but if you know the final date you
might be able to use the first record as a bench mark and figure
subsequent dates from there.
IDL> t1=17590104 & t0 = 17067072
IDL> print, t1-t0
523032
IDL> print,(2007-1948)*365.25*24.
517194.
Cheers,
Ben
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