The QuickDRI model uses 2 vegetation, 2 hydrologic (evapotranspiration and soil moisture), 1 climate, and 4 static biophysical variables to estimate drought intensification or improvement conditions scaled using the Standardized Precipitation Evaporation Index (SPEI) dryness intensity characterization scheme based on weekly models developed using a regression tree analysis method applied to the historical data record of all input variables.
Specifically, the following 9 input variables are used:
Vegetation Condition Variables
The MODIS-based Standardized Vegetation Index (SVI) and Start of Season Anomaly (SOSA), produced by USGS EROS.
The 4-week Evaporative Stress Index Anomaly (ESI), produced by USDA ARS.
The VIC Monthly Anomaly (VMA), which is the monthly anomaly of soil moisture in the top 1-meter in the North American Land Data Assimilation System Phase 2 (NLDAS-2) Variable Infiltration Capacity (VIC) land surface model (LSM). NLDAS is a collaboration project between NOAA/NCEP and NASA/GSFC. NLDAS Phase 2 runs operationally at NOAA/NCEP, and NASA/GSFC provides a customized VIC monthly anomaly product specifically for QuickDRI.
The 1-month Standardized Precipitation Index (SPI), produced with cooperation of the High Plains Regional Climate Center (HPRCC).
Root-zone Available Water Storage (AWS or AWC) (gSSURGO 2016 produced by USDA NRCS)
Digital Elevation Model (GMTED2010 mn75 produced by USGS EROS)
MODIS-based Irrigated Agriculture Dataset (MIrAD-US 2007 produced by the USGS EROS)
National Land Cover Database (NLCD 2006 produced by USGS EROS)