@prefix skos: <http://www.w3.org/2004/02/skos/core#> .

<https://gcmd.earthdata.nasa.gov/kms/concept/52347642-9786-4b59-be77-02e9f307118d>
  skos:prefLabel "PRECIPITATION INDICES"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/7427fb2d-43b5-478a-960d-2ff9aa398462> .

<https://gcmd.earthdata.nasa.gov/kms/concept/7427fb2d-43b5-478a-960d-2ff9aa398462>
  skos:changeNote """2012-06-27 10:18:45.0 [mpmorahan] Move Concepts 
add broader relation (STANDARDIZED PRECIPITATION INDEX [7427fb2d-43b5-478a-960d-2ff9aa398462,23155] - PRECIPITATION INDICES [52347642-9786-4b59-be77-02e9f307118d,39663]); 
delete broader relation (null); 
""" ;
  skos:definition """The SPI was formulated by Tom Mckee, Nolan Doesken and John Kleist of
the Colorado Climate Center in 1993. The purpose is to assign a single
numeric value to the precipitation which can be compared across
regions with markedly different climates. Technically, the SPI is the
number of standard deviations that the observed value would deviate
from the long-term mean, for a normally distributed random
variable. Since precipitation is not normally distributed, a
transformation is first applied so that the transformed precipitation
values follow a normal distribution.
The Standardized Precipitation Index was designed to explicitly
express the fact that it is possible to simultaneously experience wet
conditions on one or more time scales, and dry conditions at other
time scales, often a difficult concept to convey in simple terms to
decision-makers. Consequently, a separate SPI value is calculated for
a selection of time scales, covering the last 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 11, 12, 15, 18, 24, 30, 36, 48, 60, and 72 months, and ending
on the last day of the latest month."""@en ;
  skos:prefLabel "STANDARDIZED PRECIPITATION INDEX"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/sciencekeywords> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/52347642-9786-4b59-be77-02e9f307118d> ;
  a skos:Concept .