Dust radiation effect on the weather and dust transport over the Taklimakan Desert, China

Abstract

The regional and longer-duration dust weather in the Taklimakan Desert (TD) is mostly caused by the east-pathway dust events, which bring large amounts of dust aerosol to impact the local weather and air quality, but the dust-induced radiation feedback on meteorological processes and the dust cycle in TD is still unclear. Both dust absorption and scattering of shortwave (SW) and longwave (LW) radiation are important for dust radiation feedback (DRF), while most numerical simulations neglect the dust LW scattering effect. In this paper, we modify WRF-Chem v3.8.1 (Weather Research and Forecasting model coupled with chemistry) to include the full dust radiation effect in an only-dust simulation. Three east-pathway TD dust events were simulated by this modified WRF-Chem. For each dust event, four sensitive experiments were conducted: with SW + LW DRF, with only SW DRF, with only LW DRF, and without DRF. The modified WRF-Chem can reproduce the dust evolution and reasonably simulate the DRF. DRF enhances the mean 2-m air temperature (T2m) field by ∼1 °C in the TD and lowers the daily T2m range in the southern TD by 1.9–4.3 °C. The positive feedback of mean T2m owns mostly to two equally important contributors, i.e., the dust LW radiation impact and the synergistic impact between dust SW and LW radiation quantified by the factor separation technique. For these dust events, DRF enhances both dust loading (10–20%) and dust deposition in most TD areas, but with different impacts on the dust emission in the hinter (increasing) and the southern edge (decreasing) of the TD area. With a dynamic lift caused by mountain forcing and the DRF, the dust plume could be lifted higher in the southern TD.