Mapping Long-Term Trends in Actual Evapotranspiration in Data-Scarce conditions in Afghanistan

The agricultural sector in Afghanistan, the highest consumer of water resources, is crucial for food production and employment for over 50% of the population. As one of the top four most vulnerable countries to climate change, monitoring actual evapotranspiration (ETa) is imperative. However, conducting detailed investigations in countries facing data scarcity, like Afghanistan, remains challenging. Therefore, this study uses the TerraClimate dataset (4.6 km spatial resolution) to explore long-term ETa variation and trends in the Kabul River Basin (KRB). Integrating remote sensing data with advanced analytics, we examine the spatial and temporal dynamics of ETa in the Alingar watershed, a KRB subbasin. The results show that from 1980 to 2023, the mean annual ETa was 364±38mm. The Mann-Kendall test showed a significant trend (p-value < 0.05). This comprehensive investigation provides critical information for sustainable water management in Afghanistan.