Drought monitoring is based on the analysis of a series of drought indicators, representing different components of the hydrological cycle (e.g. precipitation, soil moisture, reservoir levels, river flow, groundwater levels) or specific impacts (e.g. vegetation water stress) that are associated with a particular type of drought. The indicators generally represent statistical anomalies of the current situation with respect to the long-term climatology at a given location and period of time, and so they provide a measure of the probabilistic severity of a given event.

What Drought Indicators are monitored?

Standardized Precipitation Index (SPI)

This indicator measures anomalies of accumulated precipitation during a given period (e.g. 1, 3, 12 months), and is the most commonly used indicator for detecting …

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Soil Moisture Anomaly (SMA)

This indicator measures anomalies of daily soil moisture (water) content, and is used to measure the start and duration of agricultural drought conditions.

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Combined Drought Indicator (CDI)

This indicator integrates information on anomalies of precipitation, soil moisture and satellite-measured vegetation condition, into a single index that is used to monitor both the …

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Anomaly of Vegetation Condition (FAPAR Anomaly)

This indicator measures anomalies of satellite-measured FAPAR (Fraction of Absorbed Photosynthetically Active Radiation), and is used to highlight areas of relative vegetation stress due to …

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