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Objective Xinjiang, recognized as a crucial coal resource area and strategic reserve in China, possesses abundant coal resources. The Zhundong coalfield, a large-scale open-pit mining area within this region, significantly contributes to increased concentrations of light-absorbing aerosols due to its coal production activities and associated industrial processes. These activities also produce substantial amounts of black carbon (BC), which, through atmospheric transport, mixes with snow and ice, influencing glacier ablation in the Tianshan Mountains. While previous studies on the Zhundong coalfield have predominantly concentrated on the ecological pollution resulting from mining activities, they have overlooked the implications for climate and radiative forcing in the area. In this context, it is crucial to employ satellite remote sensing technology to analyze and assess the optical properties and radiative forcing effects of light-absorbing aerosols in the Zhundong coalfield region. Such an approach is significant for understanding the regional environmental and climatic impacts associated with the development of open-pit coal resources in the arid regions of western China. Methods We investigate the temporal and spatial characteristics of aerosol optical depth (AOD) in the Zhundong coalfield by utilizing MODIS aerosol product (MOD04_L2) data spanning from 2005 to 2020. To simulate aerosol particle size information, a Mie scattering model is employed under the core-shell assumption. An uncertainty interval of 0.03 is selected to estimate the possible range of particle sizes within each grid, constrained by maximum and minimum values. The intersection of these constraints is then used to calculate the optical parameters for various particle size combinations. Additionally, the influence of sand and dust aerosols is considered by setting the single scattering albedo (SSA) range for these aerosols between 0.93 and 0.96. The simulated extinction coefficient (sigma(ext)) is used as a threshold value; any portion smaller than this threshold is excluded to quantify the concentration of local BC columns. Finally, the radiative forcing effect of light-absorbing aerosols in the Zhundong coalfield over the past decade is evaluated using the SBDART radiative transfer model. Results and Discussions The AOD in the Zhundong coalfield exhibited pronounced spatial heterogeneity from 2005 to 2020, with high AOD values predominantly concentrated in the mining area and its surrounding regions (Fig. 2). Seasonal variations reveal the highest concentrations in spring and winter, followed by fall, with the lowest levels observed in summer. During spring and winter, AOD values generally exceed 0.15, except in certain desert areas. Interannual fluctuations in AOD are frequent, marked by significant turning points in 2010, 2012, and 2017 (Fig. 3), which indicates that coal production, energy restructuring, and capacity reduction policies have a significant effect on air quality in mining regions. The inter-monthly variation displays a distinct U pattern (Fig. 3), with AOD peaking at 0.27 in February, which highlights the substantial influence of anthropogenic activities on regional air quality. Dusty weather in spring emerges as a dominant factor. Overall, the temporal variation in AOD in the Zhundong coalfield reflects the combined effects of natural factors and human activities. In the Wucaiwan and Dajing mining areas, the range of BC number density is (1?3)x10(18) grid(-1) (Fig. 6). In 2012, against the backdrop of China's coal economic performance, open-pit mining was less affected by the decline in production growth due to its larger production capacity and lower costs, influenced by mining methods, climatic conditions, and economic activities. In contrast, shaft mining is more heavily affected by safety risks and environmental constraints, which may lead to production limitations, especially under strengthened policy and regulatory measures. As a result, there are greater fluctuations in BC number density in the Dajing mining area (Fig. 6). The range of BC number density is 20?40 kg/grid, with seasonal variations largely consistent, although peak months differed. This suggests that BC mass concentration is closely related to particle aging and size (Fig. 7). Radiative forcing values at the top of the atmosphere, at the surface, and within the atmosphere showed varying degrees of decrease between 2011 and 2017, followed by a gradual increase. This suggests that reducing emissions of light-absorbing aerosols from mining sites can effectively lower regional radiative forcing values in the context of reduced coal production (Fig. 10). Radiative forcing values are higher in March and April during spring, when BC is aged and mixed with other aerosol components through mutual encapsulation, which results in more complex microphysical-chemical properties. This process enhances the absorption capacity of BC for both short- and long-wave radiations (Fig. 10). Conclusions We analyze the overall change in AOD in the Zhundong coalfield from 2005 to 2020 using the MODIS aerosol dataset. By integrating a meter scattering model to simulate optical parameters under various particle size combinations and constraining these simulations with single scattering albedo (SSA) observations from MODIS, this approach allows us to determine the eligible particle size information and optical parameters, enabling the calculation of BC mass concentration within the atmospheric column of the Zhundong coalfield. Subsequently, the area's radiative forcing is estimated using the SBDART radiative transfer model. The findings reveal several key insights. 1) The changes in AOD are closely linked to policy implementation and economic activities within the coal mining area. Interannual variations indicate that AOD peaked in 2012 and subsequently declined, which suggests that policies and economic activities significantly affect AOD levels. Seasonally, AOD is higher in spring and winter and lower in summer. The unique topographic and meteorological conditions facilitate the transport of BC from the mining area to other regions, which highlights the combined effects of seasonal meteorological conditions and human activities. 2) The column concentration of light-absorbing aerosols in the coal mine area is affected by both anthropogenic activities and meteorological conditions, particularly during sandy and dusty weather. A comparison of column concentrations between the Wucaiwan and Dajing mines shows that open-pit mining adapts more effectively in 2012, given the context of China's coal economic operations, whereas shaft mining may face greater challenges. 3) By examining the changes in AOD and light-absorbing aerosols, it is evident that reducing emissions of light-absorbing aerosols from coal mining areas can effectively decrease regional radiative forcing values in the short term. Inter-monthly variations reveal that atmospheric radiative forcing trends differ from those at the surface and the top of the atmosphere, with the latter two being closely related to the optical properties of light-absorbing aerosols. In spring, the frequent occurrence of sand and dust facilitates the mixing of BC with other substances, forming light-absorbing aerosols with a core-shell structure. This significantly enhances the light-absorbing capacity of BC, thereby increasing radiative forcing.

来源平台：ACTA OPTICA SINICA