The Standardized Drought Analysis Toolbox (SDAT) offers a generalized framework for deriving nonparametric standardized drought indices. Current indicators suffer from deficiencies including temporal inconsistency, and statistical incomparability. Different indicators have varying scales and ranges and their values cannot be compared with each other directly. Most drought indicators rely on a representative parametric probability distribution function that fits the data. However, a parametric distribution function may not fit the data, especially in continental/global scale studies. SDAT is based on a nonparametric framework that can be applied to different climatic variables including precipitation, soil moisture and relative humidity, without having to assume representative parametric distributions. The most attractive feature of the framework is that it leads to statistically consistent drought indicators based on different variables.
SDAT can be used to generate nonparametric standardized drought indicators such as:
- Standardized Precipitation Index (SPI),
- Standardized Soil Moisture Index (SSI),
- Standardized Runoff Index (SRI)
- Standardized Streamflow Index (SSFI),
- Standardized Relative Humidity Index (SRHI),
- Standardised Groundwater level Index (SGI),
- Standardized Surface Water Supply Index (SSWSI),
- Standardized Water Storage Index (SWSI).
Hao Z., AghaKouchak A., Nakhjiri N., Farahmand A., 2014, Global Integrated Drought Monitoring and Prediction System, Scientific Data, 1:140001, 1-10, doi: 10.1038/sdata.2014.1. (pdf)
Farahmand A., AghaKouchak A., 2015, A Generalized Framework for Deriving Nonparametric Standardized Drought Indicators, Advances in Water Resources, 76, 140-145, doi: 10.1016/j.advwatres.2014.11.012. (pdf)