Bingliang Zhuang

The climate effects of black carbon (BC) remain highly uncertain, and one critical process that requires accurate representation in climate models is BC aging. This study implements a dynamic aging scheme, which accounts for both condensation and coagulation processes, into the regional climate and chemistry coupled model RegCM-Chem to evaluate the BC climate effects over East Asia in summer. Results indicate that in heavily polluted regions such as the North China Plain and the Sichuan Basin, the BC aging timescale is shorter than 10 h, promoting the formation and wet deposition of hydrophilic BC, which reduces the BC column burden over East Asia by an average of 0.12 mg m ⁻² . Conversely, BC surface concentrations and optical depth exhibit an increase over eastern China due to the compensation of reduced dry deposition. The strengthened BC direct effects favor the development of the East Asian summer monsoon and enhance moisture convergence and cloud fraction in southern China. Additionally, accelerated aging also promotes increases in cloud droplet number concentrations and cloud optical depth. Under the dynamic aging scheme, the effective radiative forcing at the top of the atmosphere over East Asia due to BC–radiation interactions, BC–cloud interactions and BC–radiation–cloud interactions are +3.60, −0.58 and +0.90 W m ⁻² , respectively. The climate effects of BC exhibit pronounced nonlinearity driven by adjustments in circulation and cloud. Overall, BC induces a much drier and warmer surface in northern China, whereas southern China experiences the opposite effect.

The climate effects of black carbon (BC) remain highly uncertain, and one critical process that requires accurate representation in climate models is BC aging. This study implements a dynamic aging scheme, which accounts for both condensation and coagulation processes, into the regional climate and chemistry coupled model RegCM-Chem to evaluate the BC climate effects over East Asia in summer. Results indicate that in heavily polluted regions such as the North China Plain and the Sichuan Basin, the BC aging timescale is shorter than 10 hours, promoting the formation and wet deposition of hydrophilic BC, which reduces the BC column burden over East Asia by an average of 0.12 mg m⁻². Conversely, BC surface concentrations and optical depth exhibit an increase over eastern China due to the compensation of reduced dry deposition. The strengthened BC direct effects favor the development of the East Asian summer monsoon and enhance moisture convergence and cloud fraction in southern China. Additionally, accelerated aging also promotes increases in cloud droplet number concentrations and cloud optical depth. Under the dynamic aging scheme, the effective radiative forcing at the top of the atmosphere over East Asia due to BC–radiation interactions, BC–cloud interactions and BC–radiation–cloud interactions are +3.60, −0.58 and +0.90 W m⁻², respectively. The climate effects of BC exhibit pronounced nonlinearity driven by adjustments in circulation and cloud. Overall, BC induces a much drier and warmer surface in northern China, whereas southern China experiences the opposite effect.

The climate effects of black carbon (BC) remain highly uncertain, and one critical process that requires accurate representation in climate models is BC aging. This study implements a dynamic aging scheme, which accounts for both condensation and coagulation processes, into the regional climate and chemistry coupled model RegCM-Chem to evaluate the BC climate effects over East Asia in summer. Results indicate that in heavily polluted regions such as the North China Plain and the Sichuan Basin, the BC aging timescale is shorter than 10 hours, promoting the formation and wet deposition of hydrophilic BC, which reduces the BC column burden over East Asia by an average of 0.12 mg m⁻². Conversely, BC surface concentrations and optical depth exhibit an increase over eastern China due to the compensation of reduced dry deposition. The strengthened BC direct effects favor the development of the East Asian summer monsoon and enhance moisture convergence and cloud fraction in southern China. Additionally, accelerated aging also promotes increases in cloud droplet number concentrations and cloud optical depth. Under the dynamic aging scheme, the effective radiative forcing at the top of the atmosphere over East Asia due to BC–radiation interactions, BC–cloud interactions and BC–radiation–cloud interactions are +3.60, −0.58 and +0.90 W m⁻², respectively. The climate effects of BC exhibit pronounced nonlinearity driven by adjustments in circulation and cloud. Overall, BC induces a much drier and warmer surface in northern China, whereas southern China experiences the opposite effect.

The climate effects of black carbon (BC) remain highly uncertain, and one critical process that requires accurate representation in climate models is BC aging. This study implements a dynamic aging scheme, which accounts for both condensation and coagulation processes, into the regional climate and chemistry coupled model RegCM-Chem to evaluate the BC climate effects over East Asia in summer. Results indicate that in heavily polluted regions such as the North China Plain and the Sichuan Basin, the BC aging timescale is shorter than 10 hours, promoting the formation and wet deposition of hydrophilic BC, which reduces the BC column burden over East Asia by an average of 0.12 mg m⁻². Conversely, BC surface concentrations and optical depth exhibit an increase over eastern China due to the compensation of reduced dry deposition. The strengthened BC direct effects favor the development of the East Asian summer monsoon and enhance moisture convergence and cloud fraction in southern China. Additionally, accelerated aging also promotes increases in cloud droplet number concentrations and cloud optical depth. Under the dynamic aging scheme, the effective radiative forcing at the top of the atmosphere over East Asia due to BC–radiation interactions, BC–cloud interactions and BC–radiation–cloud interactions are +3.60, −0.58 and +0.90 W m⁻², respectively. The climate effects of BC exhibit pronounced nonlinearity driven by adjustments in circulation and cloud. Overall, BC induces a much drier and warmer surface in northern China, whereas southern China experiences the opposite effect.

The climate effects of black carbon (BC) remain highly uncertain, and one critical process that requires accurate representation in climate models is BC aging. This study implements a dynamic aging scheme, which accounts for both condensation and coagulation processes, into the regional climate and chemistry coupled model RegCM-Chem to evaluate the BC climate effects over East Asia in summer. Results indicate that in heavily polluted regions such as the North China Plain and the Sichuan Basin, the BC aging timescale is shorter than 10 hours, promoting the formation and wet deposition of hydrophilic BC, which reduces the BC column burden over East Asia by an average of 0.12 mg m⁻². Conversely, BC surface concentrations and optical depth exhibit an increase over eastern China due to the compensation of reduced dry deposition. The strengthened BC direct effects favor the development of the East Asian summer monsoon and enhance moisture convergence and cloud fraction in southern China. Additionally, accelerated aging also promotes increases in cloud droplet number concentrations and cloud optical depth. Under the dynamic aging scheme, the effective radiative forcing at the top of the atmosphere over East Asia due to BC–radiation interactions, BC–cloud interactions and BC–radiation–cloud interactions are +3.60, −0.58 and +0.90 W m⁻², respectively. The climate effects of BC exhibit pronounced nonlinearity driven by adjustments in circulation and cloud. Overall, BC induces a much drier and warmer surface in northern China, whereas southern China experiences the opposite effect.

The climate effects of black carbon (BC) remain highly uncertain, and one critical process that requires accurate representation in climate models is BC aging. This study implements a dynamic aging scheme, which accounts for both condensation and coagulation processes, into the regional climate and chemistry coupled model RegCM-Chem to evaluate the BC climate effects over East Asia in summer. Results indicate that in heavily polluted regions such as the North China Plain and the Sichuan Basin, the BC aging timescale is shorter than 10 hours, promoting the formation and wet deposition of hydrophilic BC, which reduces the BC column burden over East Asia by an average of 0.12 mg m⁻². Conversely, BC surface concentrations and optical depth exhibit an increase over eastern China due to the compensation of reduced dry deposition. The strengthened BC direct effects favor the development of the East Asian summer monsoon and enhance moisture convergence and cloud fraction in southern China. Additionally, accelerated aging also promotes increases in cloud droplet number concentrations and cloud optical depth. Under the dynamic aging scheme, the effective radiative forcing at the top of the atmosphere over East Asia due to BC–radiation interactions, BC–cloud interactions and BC–radiation–cloud interactions are +3.60, −0.58 and +0.90 W m⁻², respectively. The climate effects of BC exhibit pronounced nonlinearity driven by adjustments in circulation and cloud. Overall, BC induces a much drier and warmer surface in northern China, whereas southern China experiences the opposite effect.

China's Clean Air Action (CAA) plan implemented since 2013 has significantly altered atmospheric composition, and yet its impact on the terrestrial carbon sink remains unclear. This study employed the Regional Earth System Model (RegESM), an online-coupled climate–chemistry–ecosystem modeling framework, to quantify the impacts of aerosols, surface ozone (O3), and nitrogen deposition on China's net ecosystem productivity (NEP) from 2010 to 2020. The results show that aerosols enhanced China's NEP by 17.93 TgC yr−1 (4.49 % of the total NEP), primarily by increasing diffuse radiation, with the most pronounced effects in Southern and Eastern China. Nitrogen deposition further increased NEP by 37.98 TgC yr−1 (9.52 %), concentrated in Central and Southern regions. In contrast, O3 pollution reduced NEP by 51.33 TgC yr−1 (12.90 %), particularly in the forest-dominated Southeast. The positive impacts of aerosols and nitrogen deposition on the carbon sink weakened over time, whereas the negative influence of O3 was increasing. The combined effects indicate that CAA-induced atmospheric chemistry changes led to a shift in the dominant atmospheric drivers of China's terrestrial carbon sink, from enhancement by aerosols and nitrogen deposition to suppression by ozone. Our findings highlight the need for stronger O3 pollution control to achieve co-benefits between air-quality improvement and carbon neutrality.

Aerosol‐ice cloud interaction represents a critical issue in the climate system. Unlike warm clouds, ice clouds still lack parameterizations in current Regional Climate and Chemistry Model (RegCM‐Chem), leading to uncertainties in investigating the regional climate in East Asia. This study introduces an ice‐nucleation parameterization into RegCM‐Chem to investigate the climatic effects of ice nucleation by typical natural (dust) and anthropogenic (carbonaceous and sulfate) aerosols. Model results indicate that the ice nucleation of aerosols exerts a radiative heating effect over East Asia. Ice clouds could reflect incoming shortwaves and trap outgoing longwaves simultaneously, with the longwave effect dominant. Dust is the dominant aerosol in the ice cloud effect, contributing ∼70% of the total warming. Dust‐induced nucleation could lead to widespread surface warming (0.17 K) and generates cyclonic anomalies, ultimately resulting in reduced precipitation over inland China (−0.28 mm·day ⁻¹ ) and increased precipitation over the Indochina Peninsula and eastern India (0.34 and 0.17 mm·day ⁻¹ , respectively). Ice nucleation of typical anthropogenic aerosols might result in cyclonic anomalies over northeastern China and anticyclonic anomaly over southern China. This effect subsequently affects moisture transportation, which suppresses low‐level cloud formation and precipitation over southern China (−0.61% and −0.13 mm·day ⁻¹ ) while enhancing them over northeastern China (0.46% and 0.08 mm·day ⁻¹ ). The ice cloud effect of anthropogenic aerosols mainly arises from the impact of low‐level clouds on the radiative budget. Changes in low‐level cloud cover are accompanied by an inverse temperature response.

China's Clean Air Action (CAA) plan implemented since 2013 has significantly altered atmospheric composition, and yet its impact on the terrestrial carbon sink remains unclear. This study employed the Regional Earth System Model (RegESM), an online-coupled climate–chemistry–ecosystem modeling framework, to quantify the impacts of aerosols, surface ozone (O₃), and nitrogen deposition on China’s net ecosystem productivity (NEP) from 2010 to 2020. The results show that aerosols enhanced China’s NEP by 17.93 TgC yr^-1 (4.49 % of the total NEP), primarily by increasing diffuse radiation, with the most pronounced effects in Southern and Eastern China. Nitrogen deposition further increased NEP by 37.98 TgC yr^-1 (9.52 %), concentrated in Central and Southern regions. In contrast, O₃ pollution reduced NEP by 51.33 TgC yr^-1 (12.9 %), particularly in the forest-dominated Southeast. The positive impacts of aerosols and nitrogen deposition on the carbon sink weakened over time, whereas the negative influence of O₃ was increasing. The combined effects indicate that CAA-induced atmospheric chemistry changes reversed the dominant atmospheric drivers of China’s terrestrial carbon sink, from enhancement by aerosols and nitrogen deposition to suppression by ozone. Our findings highlight the need for stronger O₃ pollution control to achieve co-benefits between air-quality improvement and carbon neutrality.