Fig 1.
Location map of Afghanistan.
Fig 2.
Mean monthly P (left axis) and PET (right axis) time series at national scale over the study period 1980–2017.
Fig 3.
Mean annual P (a) and PET (b) at sub-catchment scale over the period 1980–2017.
Table 1.
Results for minimum and maximum temperature from the tenfold-cross validation.
The temperatures highlighted (in bold) identify the best results.
Table 2.
Drought index and characteristics analysed in this study.
Fig 4.
Temporal distribution of the mean SPEI at sub-catchment scale in Afghanistan for each year from 1980 to 2017: (a) monthly (SPEI-1), (b) seasonal (SPEI-3) and (c) annual (SPEI-12). The prolonged drought period from 1999 to 2004 is highlighted. Blue dotted line = Mild Drought, green dotted line = Moderate Drought, purple dotted line = Severe Drought; and red dotted line = Extreme Drought.
Fig 5.
Spatial distribution of the mean annual drought index (SPEI-12) at sub-catchment scale in Afghanistan for each year between 1980 and 2017.
Fig 6.
Spatial distribution of mean annual drought frequency at sub-catchment scale in Afghanistan for each year between 1980 and 2017 based on SPEI-1 (monthly scale).
Fig 7.
Spatial distribution of mean annual maximum drought duration at sub-catchment scale in Afghanistan for each year between 1980 and 2017 based on SPEI-1 (monthly scale).
Fig 8.
Spatial distribution of annual maximum drought duration at sub-catchment scale in Afghanistan for each year between 1980 and 2017 based on SPEI-3 (seasonal scale).
Fig 9.
Areas (1999–2011) associated with the categories of (a) medium-to-extremely long drought duration, and (b) moderate-to-extreme drought severity.
Fig 10.
Spatial distribution of annual maximum drought severity at sub-catchment scale in Afghanistan for each year between 1980 and 2017 based on SPEI-1 (monthly scale).
Fig 11.
Long-term annual maximum drought duration at sub-catchment scale in Afghanistan (1980–2017) based on SPEI-3.