Strong Dependence of Atmospheric Feedbacks on Mixed‐Phase Microphysics and Aerosol‐Cloud Interactions in HadGEM3

Abstract Anthropogenic aerosols serve as a source of both cloud condensation nuclei (CCN) and ice nuclei (IN) and affect microphysical properties of clouds. Increasing aerosol number concentration is assumed to retard the cloud droplet coalescence and the riming process in mixed-phase orographic clouds, thereby decreasing orographic precipitation. In this study, idealized 3D simulations are conducted to investigate aerosol–cloud interactions in mixed-phase orographic clouds and the possible impact of anthropogenic and natural aerosols on orographic precipitation. Two different types of aerosol anomalies are considered: naturally occurring mineral dust and anthropogenic black carbon. In the simulations with a dust aerosol anomaly, the dust aerosols serve as efficient ice nuclei in the contact mode, leading to an early initiation of the ice phase in the orographic cloud. As a consequence, the riming rates in the cloud are increased, leading to increased precipitation efficiency and enhancement of orographic precipitation. The simulations with an anthropogenic aerosol anomaly suggest that the mixing state of the aerosols plays a crucial role because coating and mixing may cause the aerosols to initiate freezing in the less efficient immersion mode rather than by contact nucleation. It is found that externally mixed black carbon aerosols increase riming in orographic clouds and enhance orographic precipitation. In contrast, internally mixed black carbon aerosols decrease the riming rates, leading in turn to a decrease in orographic precipitation.

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Supplementary material to "Aerosol-cloud interactions in mixed-phase convective clouds. Part 2: Meteorological ensemble"

10.5194/acp-2018-167-supplement ◽

2018 ◽

Author(s):

Annette K. Miltenberger ◽

Paul R. Field ◽

Adrian A. Hill ◽

Ben J. Shipway ◽

Jonathan M. Wilkinson

Keyword(s):

Mixed Phase ◽

Convective Clouds ◽

Aerosol Cloud ◽

Supplementary Material ◽

Aerosol Cloud Interactions

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Investigation of aerosol–cloud interactions using a chemical transport model constrained by satellite observations

Tellus B ◽

10.3402/tellusb.v62i1.16514 ◽

2010 ◽

Vol 62 (1) ◽

Author(s):

Yan Feng ◽

V. Ramanathan

Keyword(s):

Transport Model ◽

Chemical Transport ◽

Satellite Observations ◽

Chemical Transport Model ◽

Aerosol Cloud ◽

Aerosol Cloud Interactions

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Significant underestimation of radiative forcing by aerosol–cloud interactions derived from satellite-based methods

Nature Communications ◽

10.1038/s41467-021-23888-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Hailing Jia ◽

Xiaoyan Ma ◽

Fangqun Yu ◽

Johannes Quaas

Keyword(s):

Radiative Forcing ◽

Cloud Fraction ◽

Future Climate Change ◽

Satellite Measurements ◽

Aerosol Cloud ◽

Fine Mode ◽

Sampling Biases ◽

Aerosol Cloud Interactions ◽

Significant Underestimation ◽

Weak Satellite

AbstractSatellite-based estimates of radiative forcing by aerosol–cloud interactions (RFaci) are consistently smaller than those from global models, hampering accurate projections of future climate change. Here we show that the discrepancy can be substantially reduced by correcting sampling biases induced by inherent limitations of satellite measurements, which tend to artificially discard the clouds with high cloud fraction. Those missed clouds exert a stronger cooling effect, and are more sensitive to aerosol perturbations. By accounting for the sampling biases, the magnitude of RFaci (from −0.38 to −0.59 W m−2) increases by 55 % globally (133 % over land and 33 % over ocean). Notably, the RFaci further increases to −1.09 W m−2 when switching total aerosol optical depth (AOD) to fine-mode AOD that is a better proxy for CCN than AOD. In contrast to previous weak satellite-based RFaci, the improved one substantially increases (especially over land), resolving a major difference with models.

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100 Years of Progress in Cloud Physics, Aerosols, and Aerosol Chemistry Research

Meteorological Monographs ◽

10.1175/amsmonographs-d-18-0024.1 ◽

2019 ◽

Vol 59 ◽

pp. 11.1-11.72 ◽

Cited By ~ 4

Author(s):

Sonia M. Kreidenweis ◽

Markus Petters ◽

Ulrike Lohmann

Keyword(s):

Radiative Forcing ◽

Cloud Microphysics ◽

Climate System ◽

Mitigation Strategies ◽

Climate Projections ◽

Weather Modification ◽

Theoretical Understanding ◽

Aerosol Cloud ◽

Chemistry Research ◽

Aerosol Cloud Interactions

Abstract This chapter reviews the history of the discovery of cloud nuclei and their impacts on cloud microphysics and the climate system. Pioneers including John Aitken, Sir John Mason, Hilding Köhler, Christian Junge, Sean Twomey, and Kenneth Whitby laid the foundations of the field. Through their contributions and those of many others, rapid progress has been made in the last 100 years in understanding the sources, evolution, and composition of the atmospheric aerosol, the interactions of particles with atmospheric water vapor, and cloud microphysical processes. Major breakthroughs in measurement capabilities and in theoretical understanding have elucidated the characteristics of cloud condensation nuclei and ice nucleating particles and the role these play in shaping cloud microphysical properties and the formation of precipitation. Despite these advances, not all their impacts on cloud formation and evolution have been resolved. The resulting radiative forcing on the climate system due to aerosol–cloud interactions remains an unacceptably large uncertainty in future climate projections. Process-level understanding of aerosol–cloud interactions remains insufficient to support technological mitigation strategies such as intentional weather modification or geoengineering to accelerating Earth-system-wide changes in temperature and weather patterns.

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Ocean Emission Effects on Aerosol-Cloud Interactions: Insights from Two Case Studies

Advances in Meteorology ◽

10.1155/2010/301395 ◽

2010 ◽

Vol 2010 ◽

pp. 1-9 ◽

Cited By ~ 8

Author(s):

Armin Sorooshian ◽

Hanh T. Duong

Keyword(s):

Case Studies ◽

Field Experiments ◽

Remote Sensing Data ◽

Anthropogenic Pollution ◽

Cloud Microphysics ◽

Marine Aerosols ◽

Aerosol Cloud ◽

First Case ◽

Wide Range ◽

Aerosol Cloud Interactions

Two case studies are discussed that evaluate the effect of ocean emissions on aerosol-cloud interactions. A review of the first case study from the eastern Pacific Ocean shows that simultaneous aircraft and space-borne observations are valuable in detecting links between ocean biota emissions and marine aerosols, but that the effect of the former on cloud microphysics is less clear owing to interference from background anthropogenic pollution and the difficulty with field experiments in obtaining a wide range of aerosol conditions to robustly quantify ocean effects on aerosol-cloud interactions. To address these limitations, a second case was investigated using remote sensing data over the less polluted Southern Ocean region. The results indicate that cloud drop size is reduced more for a fixed increase in aerosol particles during periods of higher ocean chlorophyll A. Potential biases in the results owing to statistical issues in the data analysis are discussed.

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