Rural communities in the Horn of Africa Drylands (HAD) rely on the availability of soil moisture for crop growth and groundwater for drinking. Recent negative trends in March-May rainfall (‘long rains’) have decreased soil moisture with negative consequences for the livelihoods for HAD communities, who have become increasingly vulnerable to multi-season droughts affecting crops and livestock, potentially causing famines. In contrast, the October-December (‘short rains’) season shows a generally positive trend in rainfall totals, which is punctuated by particularly wet years. However, the links between seasonal rainfall, soil moisture, and groundwater storage in HAD have not been explored. Here we show how seasonal rainfall dominates total water storage, which largely represents groundwater availability in the HAD region. We find that groundwater storage correlates strongly with seasonal rains over interannual and decadal scales, and particularly during extreme rainfall events. This indicates that intense seasonal rains disproportionately penetrate into deeper water storage below ground, making the water less susceptible to loss by evapotranspiration. This result also raises the possibility that groundwater could be exploited to offset the long rains decline and potentially mitigate their climate change impacts on soil moisture, crops, and livestock.
Arranged date for the seminar talk: Nov 16, 2020
Michael Singer is Lead Principal Investigator on the EU project DOWN2EARTH, which is one of the “sister projects” of CONFER, which is led by Bjerknes researcher Erik Kolstad. Michael is also Deputy Director of the Water Research Institute and Reader in the School of Earth & Environmental Sciences at Cardiff University, as well as a Researcher in the Earth Research Institute at University of California Santa Barbara (UCSB). He received his PhD in Environmental Science and Management from UCSB in 2003. He is a Certified Professional Hydrologist American Institute of Hydrology.
Michael’s research is focused on the regional expression of climate and climate change at and near the Earth’s surface and its impact on process responses to environmental change (climatic and anthropogenic forcing), which is currently a great scientific challenge with societal relevance. Near-surface responses to environmental change are critical to predicting the consequences of climate and land-use changes at the landscape scale, as well as for management on human/engineering timescales. Singer is, at the core, a watershed scientist with a research aim to advance theory and reduce uncertainty about the impact of humans and climate on water resources, water balance, hydrologic fluxes, erosion/sedimentation, and topographic evolution of landscapes.