[ncl-talk] How "dim_spi_n" deal with zero precipitaion and maps cdf into spi values??

[Kritanai Torsri (HAII User)]

Hi Dennis, 

Thanks for your information. That s really helpful. 

BRGs, 

Kritanai T. 


จาก: "Dennis Shea" <shea at ucar.edu> 
ถึง: "Kritanai Torsri (HAII User)" <kritanai at haii.or.th> 
สำเนา: "ncl-talk" <ncl-talk at ucar.edu> 
ส่งแล้ว: พฤหัสบดี, 30 มิถุนายน, 2016 6:31:11 AM 
เรื่อง: Re: [ncl-talk] How "dim_spi_n" deal with zero precipitaion and maps cdf into spi values?? 

NCL uses a f77 subroutine based upon a code originally created by the USA's National Climate Data Center (now known as the National Centers for Environmental Information (NCEI). It contains the following code comments. 

c OUTPUT: par1,par2,par3 parameters (mean, s.d., skewness) of 
c Pearson Type III distribution used to 
c fit the input data > 0 
c xmom1,xmom2,xmom3 l-moments of the input data > 0 
c pzero relative frequency of input data = 0 

So, without looking at the code in detail, I'd say 0s are ignored. 

If you want to see the code, I have placed the code at 

http://www.cgd.ucar.edu/~shea/spi3.f 

Good luck 

On Wed, Jun 29, 2016 at 7:39 AM, Kritanai Torsri (HAII User) < kritanai at haii.or.th > wrote: 



Dear ALL, 

Can any one help me to clarify how "dim_spi_n" deals with zero precipitation for both fitting with 2-param Gamma distribution and Pearson Type 3? 

and how it maps cumulative distribution function (cdf) into SPI values? 

Thanks in advance. 

BRGs, 

Kritanai T. 



_______________________________________________ 
ncl-talk mailing list 
ncl-talk at ucar.edu 
List instructions, subscriber options, unsubscribe: 
http://mailman.ucar.edu/mailman/listinfo/ncl-talk 





-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20160630/59c432c4/attachment.html