Sensitivity of soil dust emissions to driving factor variability in earth's main drylands

Abstract

The identification of driving factors that contribute to dust emissions holds great significance on studying global climate change. In the present study, we constructed a new index, Dust Sensitivity Index, which allowed us to identify the sensitivity of dust emissions responding to variations in driving factors over 2003–2017 in Earth's main drylands. We found that dust emissions were sensitive to driving factor variability in eastern Brazil, the southern drylands of the Sahel, eastern Africa, eastern Australia and parts of northern Eurasia, where the aridity index (AI) is relatively high. The main factor affecting the DSI varies geographically over the Earth's main dryland regions. In total, wind speed made the largest relative contribution to DOD sensitivity (11.3%), followed by soil moisture (10.8%) and vegetation (10.4%). In addition, wind, vegetation, and soil moisture interact to impose complex and varying limitations on dust activity. 39.3% of the Earth's main drylands were limited by vegetation, 31.2% by wind and 29.5% by soil moisture. Our study also demonstrates that the residual effects of previous dust-driving factors have impacts on contemporary conditions. We found that regions characterized by lower DSI values displayed the most prominent residual effects in general.