Meteorological Drought Assessment in the Ziz Watershed (South East of Morocco)

In the face of climate change, drought monitoring and characterisation is indispensable in arid and semi-arid areas. This paper represents a metrological drought assessment in the Ziz watershed located in south-eastern Morocco, through the application of four meteorological indices; RAI (Rainfall Anomaly Index), PNI (Percentage of Normal Index), SPI (Standardized Precipitation Index), ZSI (Z-Score Index). Based on rainfall data series from four stations over a time scale of 37 years (from 1983), also taking into account the relationship between these indices. The analysis of the rainfall series indicates a variability in its spatio-temporal distribution. However, the calculated drought indices indicate that the Ziz basin has experienced drought periods with their different classifications between 1983-2019, noting that the years 1986 and 2001 were dry to extremely dry in all stations of the basin. Thus, the results highlight a strong correlation between the four indices (r ≥ 0.967).