Here is an easy to use meteorological drought monitoring software (MDM). Apart from SPI, it also enables you to calculate several other indices including: deciles index, Percent of Normal Index, Rainfall Anomaly Index, effective drought index, China-Z index, modified CZI, and Z-Score Index. Your calculations can be annual, seasonal, monthly and moving averages for 3, 6, 9, 12, 18, 24, 48 months. I hope this helps!

Link: https://agrimetsoft.com/MDM.aspx

Hello,

Kindly access the link below to download the software that calculates SPI (DOS-based):

https://drought.unl.edu/droughtmonitoring/SPI/SPIProgram.aspx

You need to click on the right corner on the "download" button. There is also a manual on how to use it on the same website.

You can calculate SPI from daily, weekly and monthly rainfall data. You can try to select a twelve-months moving average window computation. The SPI model will generate monthly SPIs over a selected time-series input data.

Good luck!

Chafik

if you use software, it is easier. but SPI index based on vibal EQ, if you calculate average and Deviation from the criterion you can calculate it.

https://drought.unl.edu/droughtmonitoring/SPI/SPIProgram.aspx

Hi,

If you used R, https://rdrr.io/rforge/climstats/man/spi.html could be interesting for you.

Interesting..........................................

Very useful.

Follow

There is several tool for calculating SPI. I compared three of them and I found the tool of mitigation drought center(the above link) is same as MDM(the above link). you can read the result on my website. I can't put the link of my website here but you can find the page related to this matter by search "drainc spi gamma distribution" in google.

valuable information

Hi

I received a new compare from Dr Musa Esit about RAI.

You can find the result in AgriMetSoft by using this link

Why Rainfall Anomaly Index in MDM-DMAP-RDIT is Different than R packages

http://bit.ly/2HoXXCR

This video could be useful.

https://www.youtube.com/watch?v=dLpmUVDRFbM