3:30 PM - 3:45 PM
[AAS11-24] Influence of dust, marine organic aerosols, and bioaerosols on ice nucleation in Arctic low-level clouds under Arctic warming
Keywords:Aerosol, Cloud, Ice nucleation, Climate, Arctic
Aerosols serve as ice nucleating particles (INPs), helping in ice formation and play a crucial role in mixed-phase clouds. These clouds are widespread in the lower and middle troposphere of the Arctic, significantly influencing the Arctic climate, which is vital to the global climate system. However, the insufficient understanding of the sources and behaviors of INPs hinders accurate predictions of the Arctic climate.
In this study, we simulate INPs and their effects on ice nucleation in Arctic mixed-phase clouds to reveal the factors controlling INPs, their relative importance, and the contributions of different INP sources in the Arctic.
We use an improved climate-aerosol model, CAM-ATRAS, to conduct the simulations from 1980 to 2020. Our model incorporates dust, marine organic aerosols (MOA), and bioaerosols emitted from the Arctic region (hereafter referred to as Arctic dust, Arctic MOA, and Arctic bioaerosols), which represent the primary sources of INPs in the Arctic. Their respective ice nucleating abilities (INA) are integrated into the computational framework. INPs originating from aerosols emitted in the Arctic are referred to as Arctic INPs in our study.
The model evaluations, conducted through comparisons with field observations, show that incorporating more comprehensive INP sources improved its ability to reproduce INP observations in the Arctic region.
Previous studies have shown that the INA of aerosol decreases with increasing temperatures. Our simulations show that from 1981 to 2020, the emissions of dust, MOA, and bioaerosols in the Arctic increase due to warming-induced snow and ice retreat. However, INP concentrations in the lower troposphere decrease, except in regions with significant increases in aerosol emissions. These results suggest that changes in Arctic INPs due to Arctic warming are influenced by both increased aerosol emissions and decreased INA. The reduction in INA plays a more dominant role in decreasing INP concentrations across most areas.
Additionally, Arctic INPs dominate total INPs in the lower Arctic troposphere, with Arctic dust (36%) as the largest contributor, followed by Arctic bioaerosols (28%) and Arctic MOA (9%). Spatial, vertical, and seasonal distributions of aerosols and INPs vary significantly by species, with Arctic dust INPs dominating the central Arctic Ocean, especially in summer, while Arctic MOA INPs prevail over coastal regions, particularly in spring and winter. Arctic bioaerosol INPs primarily influence land regions during summer and early fall at temperatures around −10°C. These variations highlight the necessity of incorporating multiple INP species and selecting appropriate parameterizations in models.
These findings enhance understanding of Arctic aerosol and ice nucleation processes, providing a foundation for exploring Arctic climate feedbacks and improving projections of Arctic climate change.
In this study, we simulate INPs and their effects on ice nucleation in Arctic mixed-phase clouds to reveal the factors controlling INPs, their relative importance, and the contributions of different INP sources in the Arctic.
We use an improved climate-aerosol model, CAM-ATRAS, to conduct the simulations from 1980 to 2020. Our model incorporates dust, marine organic aerosols (MOA), and bioaerosols emitted from the Arctic region (hereafter referred to as Arctic dust, Arctic MOA, and Arctic bioaerosols), which represent the primary sources of INPs in the Arctic. Their respective ice nucleating abilities (INA) are integrated into the computational framework. INPs originating from aerosols emitted in the Arctic are referred to as Arctic INPs in our study.
The model evaluations, conducted through comparisons with field observations, show that incorporating more comprehensive INP sources improved its ability to reproduce INP observations in the Arctic region.
Previous studies have shown that the INA of aerosol decreases with increasing temperatures. Our simulations show that from 1981 to 2020, the emissions of dust, MOA, and bioaerosols in the Arctic increase due to warming-induced snow and ice retreat. However, INP concentrations in the lower troposphere decrease, except in regions with significant increases in aerosol emissions. These results suggest that changes in Arctic INPs due to Arctic warming are influenced by both increased aerosol emissions and decreased INA. The reduction in INA plays a more dominant role in decreasing INP concentrations across most areas.
Additionally, Arctic INPs dominate total INPs in the lower Arctic troposphere, with Arctic dust (36%) as the largest contributor, followed by Arctic bioaerosols (28%) and Arctic MOA (9%). Spatial, vertical, and seasonal distributions of aerosols and INPs vary significantly by species, with Arctic dust INPs dominating the central Arctic Ocean, especially in summer, while Arctic MOA INPs prevail over coastal regions, particularly in spring and winter. Arctic bioaerosol INPs primarily influence land regions during summer and early fall at temperatures around −10°C. These variations highlight the necessity of incorporating multiple INP species and selecting appropriate parameterizations in models.
These findings enhance understanding of Arctic aerosol and ice nucleation processes, providing a foundation for exploring Arctic climate feedbacks and improving projections of Arctic climate change.