[ncl-talk] dim_spi_n

[Dennis Shea]

Yes ... 12 values is not nearly enough to fit a distribution. As noted in
the documentation for the function:

http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_spi_n.shtml
*x*

*Monthly precipitation* of type 'float' or 'double' and any dimensionality.
The size of the specified *dims* must be divisible by 12. Since a
distribution is being fit, there should be a 'reasonably' large sample size.

*At least 30 years of monthly data (360=12*30) is recommended.*


*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^*



On Fri, Aug 1, 2014 at 5:14 PM, debasish mazumder <debasish at ucar.edu> wrote:

>  Hi All,
> I am trying to use function
> *dim_spi_n. *My precipitation values varies between 0 - 334 mm/month and
> precipitation time series is very small (12 months).
> I am getting strange values for SPI3. I am wondering is it because of
> length of my time series or am I missing something?
>
> with regards
> -Debasish
>
>
>
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