Changes in Dust Activity in Spring over East Asia under a Global Warming Scenario

摘要

Dust activity not only influences human health through dust storms but also affects climate at local and regional scales through the direct effects of dust aerosols on both solar and longwave radiative heating. In this study, based on dust simulations from seven Coupled Model Intercomparison Project Phase 5 (CMIP5) models, the spatial and temporal changes in dust activity over East Asia under a Representative Concentration Pathway 8.5 global warming scenario were examined for the periods of 2016–2035 (P1), 2046–2065 (P2) and 2080–2099 (P3). The results show that the multimodel ensemble mean (MME) of the CMIP5 models largely captures the spatial distribution of dust emissions and dust optical depth (DOD) over East Asia during 1986–2005 (P0). The MME reproduces the increasing trend in dust emissions and DOD over dust sources in East Asia during P0. Accompanying emission reductions during P1 to P3, the DOD simultaneously decreases, and the evident DOD decline can also be found over downwind areas in eastern China and the Korean Peninsula. Simulations project increases in precipitation and the LAI (leaf area index). Simultaneously, the weakened East Asian trough leads to anomalous southerly winds and lower wind speeds at the surface. All these results indicate unfavorable conditions for dust emissions over the sources regions, resulting in a decreased DOD over East Asia during P1 to P3.