Changing nature of Saharan dust deposition in the Carpathian Basin (Central Europe): 40 years of identified North African dust events (1979-2018)

Abstract

Several billion tonnes of mineral dust is emitted, and transported through winds every year from arid-semiarid areas. North African dust hot spots located in the Sahara are responsible for 50-70% of the global mineral dust budget. Dust-loaded air-masses originated from these sources can be transported over long distances and can also affect remote areas, such as North and South Americas, Europe, and the Middle East. In this study, we analysed 218 identified Saharan dust events (SDEs) in the Carpathian Basin (Central Europe) during 1979 to 2018. Systematic identification of SDEs and analyses of dust emission, dust source area activity, dust transporting wind systems, and transport routes revealed that different synoptic meteorological patterns are responsible for SDEs, and these are occurring mostly in spring and summer. The characteristic synoptic meteorological background of episodes was also identified, and three major types of atmospheric pressure-system patterns were distinguished. In recent years, several intense wintertime dust deposition events have been recorded in Central Europe. All of the identified unusual episodes were characterised by severe washout of mineral dust material and were related to very similar synoptic meteorological situations. Enhanced southward propagation of a high-latitude upper-level atmospheric trough to north-western Africa and orographic blocking of Atlas Mountains played an essential role in the formation of severe dust storms, whereas the long-range transport was associated with the northward branch of the meandering jet. The occurrence and southerly penetration of high-latitude upper-level atmospheric trough to low-latitudes and the increased meridionality of the dominant flow patterns may be associated with enhanced warming of the Arctic, leading to more meandering jet streams. Particles size of sampled dust material of some intense deposition episodes were very coarse with a considerable volumetric proportion of > 20 µm particles.

Keywords: Carpathian Basin; Dust deposition; Grain size; Saharan dust events.