Regional Characteristics of Recent Dust Occurrence and Its Controlling Factors in East Asia

Abstract

Aeolian dust, resulting from wind erosion, is controlled by two major factors: aeolian erosivity (i.e., wind speed) and aeolian erodibility (i.e., land surface conditions). Erodibility factors include a number of land surface parameters that interact in complicated manners. Thus far, the extent to which each of the factors contributes to dust outbreaks, which vary regionally and seasonally, remains unclear. As such, we present a novel map of the controlling factors for dust outbreaks in dryland of East Asia by quantifying the relative contributions of the erosivity and various erodibility parameters to inter-annual dust variations on a station basis during the period of 1999 to 2013. Erosivity controls dust outbreaks in the Taklimakan Desert, west of the Hexi Corridor, and on the north side of the Altai Mountain. On the other hand, dust outbreaks are dependent on erodibility in steppe regions: lower precipitation or less abundant vegetation during the previous summer was found to be related to dusty springs in the Mongolian steppe, whereas the less abundant spring vegetation and reduced snow cover enhanced dust outbreaks in the Inner Mongolian steppe. Anthropogenically restored vegetation in desertified areas was found to be likely to suppress dust outbreaks in the Loess Plateau.