Stratospheric impacts on dust transport and air pollution in West Africa and the Eastern Mediterranean

Abstract

Saharan dust intrusions strongly impact Atlantic and Mediterranean coastal regions. Today, most operational dust forecasts extend only 2–5 days. Here we show that on timescales of weeks to months, North African dust emission and transport are impacted by sudden stratospheric warmings (SSWs), which establish a negative North Atlantic Oscillation-like surface signal. Chemical transport models show a large-scale dipolar dust response to SSWs, with the burden in the Eastern Mediterranean enhanced up to 30% and a corresponding reduction in West Africa. Observations of inhalable particulate (PM10) concentrations and aerosol optical depth confirm this dipole. On average, a single SSW causes 680–2460 additional premature deaths in the Eastern Mediterranean and prevents 1180–2040 premature deaths in West Africa from exposure to dust-source fine particulate (PM2.5). Currently, SSWs are predictable 1–2 weeks in advance. Altogether, the stratosphere represents an important source of subseasonal predictability for air quality over West Africa and the Eastern Mediterranean.

Arctic amplification–induced decline in West and South Asia dust warrants stronger antidesertification toward carbon neutrality

“…Large-scale atmospheric circulation is the key driving force that affects local emission conditions as well as the long-range transport processes of dust aerosols in West and South Asia. The mid-latitude circulation pattern is subject to the influence of major climate modes (directly or indirectly via teleconnection), such as sudden stratospheric warming, Arctic ice loss, el niño/southern oscillation (ENSO), and the Indian ocean dipole (IOD) ( 33 – 35 ). Changes in large-scale circulation directly modify the direction and magnitude of long-distance dust transport ( 25 , 36 ), and also regulate emission processes by affecting regional precipitation, soil moisture and near-surface wind speed, and boundary-layer stability ( 37 , 38 ).…”