1,4,5,6,1,7- 1Faculty of Geosciences and Environment, Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland (andries-jan.devries@unil.ch)
- 2Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, PA, USA
- 3Department of Atmospheric Sciences, University of Hawaii, Mãnoa, USA
- 4Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Athens, Greece
- 5Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, Germany
- 6Climate and Atmospheric Research center (CARE-C), The Cyprus Institute, Nicosia, Cyprus
- 7Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
Interannual variability in precipitation across the arid Middle East has profound societal and environmental importance. While previous studies have identified a linkage between El Niño-Southern Oscillation (ENSO) and interannual precipitation variability in this region, this relationship and the underlying mechanisms are not fully understood. Using observation-based datasets and a range of diagnostics, this study quantifies the influence of ENSO on Middle Eastern precipitation variability during the extended cool season (October-May) and explores the underlying atmospheric drivers. Consistent with previous studies, we find that El Niño is associated with increased precipitation, whereas La Niña is associated with decreased precipitation. This relationship varies substantially within the cool season with a strong precipitation increase during autumn and a modest increase in spring under El Niño conditions, and a persistent precipitation decrease throughout the cool season under La Niña conditions. These precipitation anomalies during El Niño (La Niña) are associated with an equatorward (poleward) displacement of the subtropical jet along with increased (decreased) Rossby wave breaking frequencies at the poleward flank of the jet and underneath the jet core. Simultaneously, a mid-tropospheric cyclonic (anticyclonic) circulation anomaly over the Middle East promotes strengthened (weakened) atmospheric moisture transport into the region leading to enhanced (reduced) atmospheric moisture content across the region. From a global perspective, these regional circulation patterns result from (1) a zonally symmetric shift in the meridional position of the subtropical jet, (2) a barotropic Rossby wave response reaching from the tropical Pacific toward the Middle East via the extratropics, and (3) a baroclinic response in the tropical circulation extending westwards over the Indian Ocean and South Asia consistent with the Gill-Matsuno model. Co-varying circulation patterns over the Indian Ocean, linked to the Indian Ocean Dipole, contribute to the intraseasonally varying and asymmetric influence of ENSO on Middle Eastern precipitation. Our findings advance process understanding of precipitation variability in the water-scarce Middle East, having implications for seasonal predictions, flood and drought warnings, and the evaluation of climate model projections.
How to cite: De Vries, A. J., Feldstein, S. B., Casselman, J. W., Fragkoulidis, G., Lelieveld, J., and Domeisen, D. I. V.: The influence of El Niño-Southern Oscillation on cool-season precipitation variability in the arid Middle East, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9909, https://doi.org/10.5194/egusphere-egu26-9909, 2026.
