Weaker absorption of Asian dust than previously estimated based on observation-constrained simulation

Dust aerosols constitute a major component of shortwave-absorbing aerosols, with absorption uncertainties predominantly associated with mineral composition variations. To address this, we analyzed 22 East Asian dust (EAD) samples and derived a revised imaginary part of the complex refractive index ($$k$$), with a range spanning from $$2.26\times {10}^{-4}$$–$$8.37\times {10}^{-4}$$ in 0.3–1 μm, which is significantly lower than the Optical Properties of Aerosols and Clouds (OPAC) and the values commonly used in research on East Asian. The improved optical parameters applied to CAS-ESM2 for spring dust simulations have been shown to reduce single scattering albedo (SSA) bias from 15% to 2% and absorption aerosol optical depth (AAOD) overestimation from +5.2% to −1.7%. The modified scheme reduces atmospheric absorption by 79.5% (−7.61 W/m2) and reverses the top of atmospheric shortwave radiation effect to −3.80 W/m2. This outcome revealed that dust absorption in East Asia is weak and the climate impact is significantly different from previous assessments.