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Dust shortwave absorbability suffers from significant uncertainties. We investigated the radiative effects of dust aerosols from the circum‐Tibet region using four shortwave absorbability schemes and examined their impacts on the East Asian summer monsoon by using the Community Earth System Model (CESM). We adopted superspheroidal models to compute dust aerosol optical properties and found that more absorptive particles have larger asymmetry factor and lower single‐scattering albedo. Meiyu precipitation, as a part of the East Asian summer monsoon, is weakened by dust aerosols, particularly for the convective precipitation. The mechanism is that dust aerosols transported mainly from the Gobi desert radiatively heat the lower atmosphere to the north of the Meiyu rainband and decrease the meridional temperature gradient, leading to the weakening of the midtropospheric westerly jet over the Meiyu rainband, which is important for convection. More absorptive dust aerosols with a stronger radiative heating effect inhibit more convective Meiyu precipitation. Plain Language Summary: The circum‐Tibet region including the Taklimakan and Gobi deserts is the major source region of dust aerosols in East Asia particularly during the spring and summer seasons. Meiyu, as a part of the East Asian summer monsoon, generally occurs from mid‐June to mid‐July and often shows a tilt rain band extending from southwest to east China. The Letter reports on our finding about the relationship between dust shortwave absorbability (the amount of solar radiation absorbed by dust) and Meiyu precipitation. For weakly absorptive dust aerosols, convective Meiyu precipitation is rarely changed by dust aerosols; however, for strongly absorptive dust aerosols, convective Meiyu precipitation is significantly decreased. The impact of dust absorbability on Meiyu precipitation is explained through atmospheric heating rate, temperature, and wind field changes. This Letter emphasizes the urgent need of a more accurate knowledge of dust shortwave absorbability for climate modeling since significant uncertainties of refractive indices exist and new evidences show that Asian dust could be less absorptive than previously believed. Key Points: Dust shortwave absorbability affects single‐scattering albedo and asymmetry factorDust aerosols inhibit convective Meiyu precipitation depending on absorbabilityMidtropospheric westerly jet is weakened by dust aerosols causing decreased convective precipitation [ABSTRACT FROM AUTHOR]

• The optical properties of dust particles associated with three sets of refractive indices were compared in a spectrum region (650–1135 cm−1). • The refractive indices have a clear impact on the spectrum slope of brightness temperature. • The refractive index impacts on bright temperature are essentially associated with the height of dust layer and the aerosol optical thickness. In this paper, we modeled dust impacts on atmospheric radiative transfer in the thermal infrared region of 650–1135 cm−1 by using the radiative transfer for TOVs model (RTTOV). We assessed three sets of Asian dust refractive indices (the Volz refractive index implemented in the RTTOV as default, and the Gobi and Taklamakan refractive indices) for brightness temperature simulations. The US 76 standard profile was employed to represent the atmospheric status. Three scenarios of high (532.6~575.2 hPa), middle (661~703.6 hPa) and low (786.3~825.8 hPa) dust layers and four cases of aerosol optical thickness (AOT) (0.1, 0.5, 1.0, and 1.5 at 1000 cm−1) were considered in the simulations. It was found that the refractive indices have a clear impact on simulating the values and the spectral slope of brightness temperature in the mid-thermal infrared band. Brightness temperature difference (BTD) for different refractive indices (Gobi/Taklamakan–Volz) increases with the height of dust layer and the AOT. The BTD reaches ~4 K for the high dust layer (532.6~575.2 hPa) and the AOT of 1.5. Most BTDs (0.5–4 K) are much larger than the noise-equivalent temperature difference of high-spectral resolution infrared sounders. Even for the AOT of 0.1, BTDs for different refractive indices could be close to or larger than 0.2 K. This study emphasizes the requirement of accurate refractive indices according to dust origins for improving brightness temperature simulations and provides valuable references for potential improvement of dust retrievals. [ABSTRACT FROM AUTHOR]