Figure 3. The flow chart of the procedure used in computation of the time series SPI

From

Spatio-temporal Drought Characterization for the Upper Tana River Basin, Kenya Using Standardized Precipitation Index (SPI)

Raphael M. Wambua, Benedict M. Mutua, James M. Raude

World Journal of Environmental Engineering. 2015, 3(4), 111-120 doi:10.12691/wjee-3-4-2