Dust and sea surface temperature forcing of the 1930s "Dust Bowl" drought

Droughts over the central United States (US) are modulated by sea surface temperature (SST) variations in the eastern tropical Pacific. Many models, however, are unable to reproduce the severity and spatial pattern of the "Dust Bowl'' drought of the 1930s with SST forcing alone. We force an atmosphere general circulation model with 1930s SSTs and model-generated dust emission from the Great Plains region. The SSTs alone force a drought over the US similar to observations, but with a weaker precipitation anomaly that is centered too far south. Inclusion of dust radiative forcing, centered over the area of observed wind erosion, increases the intensity of the drought and shifts its center northward. While our conclusions are tempered by limited quantitative observations of the dust aerosol load and soil erosion during this period, our study suggests that unprecedented atmospheric dust loading over the continental US exacerbated the "Dust Bowl'' drought.