Simulated regional dust cycle in the Carpathian Basin and the Adriatic Sea region during the Last Glacial Maximum

Different climate and environmental conditions dominated in the Carpathian Basin and the adjacent northern Italy/Adriatic region during the Last Glacial Maximum (LGM), as compared to today. For instance, high dust accumulation rates recorded in loess deposits point to an active dust cycle during the LGM. We investigated the climate conditions and regional dust cycle based on high-resolution (grid spacing of ~8.5 km) regional climate simulations for LGM conditions. The model output is in good agreement with proxy data, reproducing cold and dry conditions for the LGM. Highest dust emissions are simulated to the east of the Alpine ice sheet and in the Kvarner Bay region. While simulated dust deposition plumes in the northern Carpathian Basin indicate prevailing northerly (NW, N and NE) winds during dust events, strong Bora winds flowing down the slopes of the Dinaric Alps appear to play a major role in the local to regional dust cycle in the northern Adriatic region. From a seasonal perspective, the simulated dust cycle is most active during late winter and spring. A detailed analysis of climate and environmental conditions at key areas reveals that high wind speeds and low precipitation rates during late winter and spring correlate well with high dust emissions. In contrast, lower wind speeds, increasing precipitation, and the greening of vegetation prevent high dust emissions during summer and autumn. The occurrence of cyclonic circulation patterns in the Adriatic shelf region reveals that individual cyclones played an important role in transporting dust particles from the alluvial Po plain towards the eastern Adriatic loess deposition sites.