Standard precipitation index

{
  "id": "MLC-T-MET-009195",
  "term": "Standard precipitation index",
  "field": "Meteorology and atmospheric science",
  "definition": "A probability-based index used to monitor and characterize meteorological drought by measuring precipitation anomalies over a given time period. The Standard Precipitation Index (SPI) fits historical precipitation data to a gamma distribution, which is then transformed into a normal distribution. SPI values near zero indicate normal precipitation, while negative values indicate drought and positive values indicate wet conditions, with values below -2.0 signifying extreme drought.",
  "url": "https://mlchart.com/terminology/meteorology/standard-precipitation-index/"
}