Positive correlation between dust activity and humidity in arid Central Asia during the Holocene

Abstract

A long-standing view of the paleoclimatology of arid and semiarid regions is that humid conditions inhibit dust lofting. Here, we combine proxy climate records from four loess sections in Central Asia (CA) with a transient Earth system model simulation to examine the controls on dust activity in CA during the Holocene. Dust activity and regional humidity were in-phase and there was a trend of gradual wetting and increasing dust storm intensity from the early through late Holocene. This intensified Holocene dust storm activity in CA was caused by dry conditions and the strengthening of regional wind/cyclone activity in spring, in response to winter snow depth memory. However, summer cooling and increased precipitation in the late Holocene led to increased summer and even annual wetting and hence to an increase in soil water content. Our results emphasize the importance of insolation and changes in humidity seasonality in driving the positive correlation between dust storm activity and humidity.