Drought characterisation across cocoa farming zone in Ghana and Cote d'ivoire

The analysis uses the The analysis uses the CHIRPS precipitation dataset at 5 km spatial resolution to compute the Standardized Precipitation Index (SPI) over cocoa production zones in Côte d’Ivoire and Ghana for the period 1981–2023. CHIRPS integrates satellite-based rainfall estimates with in-situ station observations, providing a long-term, high-resolution gridded precipitation product suitable for drought monitoring in data-scarce regions. SPI was calculated by standardizing monthly accumulated precipitation relative to a long-term climatological baseline. To capture hydroclimatic variability across different temporal scales relevant to agriculture, SPI was computed at 1-, 3-, 6-, and 12-month timescales (SPI-1, SPI-3, SPI-6, SPI-12). SPI-1 reflects short-term moisture conditions influencing crop establishment, SPI-3 captures seasonal rainfall variability affecting crop growth and yield development, SPI-6 represents medium-term soil moisture conditions relevant to seasonal agricultural performance, while SPI-12 characterizes long-term hydrological anomalies influencing overall water availability. The resulting SPI time series enables classification of hydroclimatic conditions into seven standardized categories ranging from extreme dryness to extreme wetness.CHIRPS precipitation.