An Overview of Aerosol‐Cloud Interactions DOI
Hamish Gordon, Franziska Glassmeier, Daniel T. McCoy

et al.

Geophysical monograph, Journal Year: 2023, Volume and Issue: unknown, P. 13 - 45

Published: Dec. 15, 2023

Aerosol-cloud interactions refer to the group of atmospheric processes by which aerosols influence cloud properties, and sometimes also clouds affect aerosols. The effect these on Earth's radiative balance is potentially large, but uncertain. When combined with uncertainties in aerosol concentrations that result from emissions processes, uncertainty aerosol-cloud dominates overall our knowledge forcing climate. Aerosols primarily changing number condensation ice nuclei, "indirect effects," temperature cloud, "semi-direct effects." Changes response may cause significant adjustments macrophysical properties such as coverage condensate amount. interaction research focuses understanding at work, mainly analyzing observation data, performing laboratory experiments, building models simulate how clouds. In this review, we outline relevant science highlight some promising techniques have been applied recently better understand their implications for balance, Gaussian process emulation. This chapter intended provide background subsequent chapters series monographs an introduction graduate students current field interactions.

Language: Английский

An Intercomparison of Large‐Eddy Simulations of a Convection Cloud Chamber Using Haze‐Capable Bin and Lagrangian Cloud Microphysics Schemes DOI Creative Commons
Fan Yang, Fabian Hoffmann, Raymond A. Shaw

et al.

Journal of Advances in Modeling Earth Systems, Journal Year: 2023, Volume and Issue: 15(5)

Published: April 29, 2023

Abstract Recent in situ observations show that haze particles exist a convection cloud chamber. The microphysics schemes previously used for large‐eddy simulations of the chamber could not fully resolve and associated processes, including their activation deactivation. Specifically, droplet was modeled based on Twomey‐type parameterizations, wherein droplets were formed when critical supersaturation available condensation nuclei (CCN) exceeded explicitly resolved. Here, we develop adapt haze‐capable bin Lagrangian to properly deactivation processes. Results are compared with CCN‐based scheme which We find results from agree well those scheme. However, both significantly differ unless CCN recycling is considered. Haze deactivated can strongly enhance number concentration due positive feedback haze‐cloud interactions particle size distributions more realistic considering solute curvature effects enable representing complete physics process. Our study suggests may have strong impact properties fluctuations comparable mean supersaturation, as case likely atmosphere, especially polluted conditions.

Language: Английский

Citations

12
Reconciling observed and predicted droplet concentration at the Indian summer monsoon cloud base DOI
Mercy Varghese, Thara Prabhakaran

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 973, P. 179077 - 179077

Published: March 22, 2025

Language: Английский

Citations

0
Improvement of Ice Particle Spectral Relative Dispersion Parameterization in the BCC‐AGCM Model and Its Impact on Global Climate Simulation DOI Creative Commons

Pengcheng Lin,

Chunsong Lu,

Xin He

et al.

Journal of Advances in Modeling Earth Systems, Journal Year: 2025, Volume and Issue: 17(5)

Published: April 30, 2025

Abstract The representation of cloud microphysical processes in climate models continues to be a major challenge leading uncertainty simulations. shape parameter (equivalent relative dispersion) gamma distribution for ice particles is assumed 0 the Beijing Climate Center Atmospheric General Circulation Model (BCC‐AGCM). This study diagnoses by linking it volume‐mean diameter and analyzes impact modified scheme on performance Results show that performs better simulating global fraction, radiative forcing, total precipitation compared control configuration, thereby significantly reducing simulation biases. underlying physical mechanisms are driven three key factors. First, greater than zero, narrowing particle size distribution. reduces autoconversion snow sedimentation while enhancing deposition growth, resulting an increase upper‐level clouds. ice‐clouds increases upper atmospheric temperatures, enhances stability, promotes formation lower‐level Second, improvement fraction mitigates underestimation longwave shortwave forcing. Additionally, overestimation improved, including both convective large‐scale precipitation, particularly from annual mean perspective. Increased stability weakened sources enhanced sinks reduce precipitation. emphasizes importance spectral dispersion provides valuable insights improving microphysics parameterization schemes.

Language: Английский

Citations

0
Distinct Mixing Regimes in Shallow Cumulus Clouds DOI Creative Commons
Y. Arieli, Eshkol Eytan, Orit Altaratz

et al.

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(2)

Published: Jan. 19, 2024

Abstract Understanding the nature of mixing between cloudy air and its surroundings is an important yet, open question. In this research, we use high‐resolution (10 m) bin‐microphysics Large Eddy Simulation a cumulus cloud, together with Lagrangian passive tracer tracking method, to study mixing. We analyze tracers as function their trajectories thermodynamic conditions they undergo inside outside cloud. Three main regimes (core, periphery, skin) are identified, each determining subset similar trajectories. These can be observed throughout cloud's lifetime provide evidence for presence undiluted core in shallow clouds. At dissipation stage, fourth regime identified: cloud‐top entrainment followed by downdrafts.

Language: Английский

Citations

3
A single-photon lidar observes atmospheric clouds at decimeter scales: resolving droplet activation within cloud base DOI Creative Commons
Fan Yang, A. B. Kostinski, Zeen Zhu

et al.

npj Climate and Atmospheric Science, Journal Year: 2024, Volume and Issue: 7(1)

Published: April 20, 2024

Abstract Clouds, crucial for understanding climate, begin with droplet formation from aerosols, but observations of this fleeting activation step are lacking in the atmosphere. Here we use a time-gated time-correlated single-photon counting lidar to observe cloud base structures at decimeter scales. Results show that air–cloud interface is not perfect boundary rather transition zone where transformation aerosol particles into droplets occurs. The observed distributions first-arriving photons within reflect vertical development cloud, including and condensational growth. Further, highly resolved profile backscattered above enables remote estimation concentration, an elusive critical property aerosol–cloud interactions. Our results feasibility remotely monitoring properties submeter scales, thus providing much-needed insights impacts atmospheric pollution on clouds aerosol-cloud interactions influence climate.

Language: Английский

Citations

3
Theoretical framework for measuring cloud effective supersaturation fluctuations with an advanced optical system DOI Creative Commons
Ye Kuang, Jiangchuan Tao,

Hanbing Xu

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(2), P. 1163 - 1174

Published: Jan. 29, 2025

Abstract. Supersaturation is crucial in cloud physics, determining aerosol activation and influencing droplet size distributions, yet its measurement remains challenging poorly constrained. This study proposes a theoretical framework to simultaneously observe critical diameter hygroscopicity of activated aerosols through direct measurements scattering water-induced enhancement interstitial aerosols, enabling effective supersaturation measurements. Advanced optical systems based on this allow minute- second-level measurements, capturing fluctuations vital microphysics. Although currently limited clouds with supersaturations below ∼ 0.2 % due small signals from sub-100 nm advancements sensors could extend applicability. Its suitability for long-term allows climatological studies fogs mountain clouds. When equipped aerial vehicles, the system also measure aloft Therefore, proposed theory serves as valuable method both short-term microphysics aerosol–cloud interaction studies.

Language: Английский

Citations

0
Simulating Droplet-Resolved Haze and Cloud Chemistry Forming Secondary Organic Aerosols in Turbulent Conditions within Laboratory and Cloud Parcels DOI
Manish Shrivastava, Jie Zhang, Steven K. Krueger

et al.

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: March 10, 2025

Most models do not explicitly simulate droplet-resolved cloud chemistry and the interactions between turbulence due to large associated computational costs. Here, we incorporate formation of isoprene epoxydiol secondary organic aerosol (IEPOX-SOA) in individual droplets within a one-dimensional explicit mixing parcel model (EMPM-Chem). We apply EMPM-Chem IEPOX-SOA using laboratory chamber configuration. find that dissolution IEPOX gases is weighted more toward larger their liquid water content (compared smaller droplets), while conversion dissolved much greater deliquesced haze particles higher acidity ionic strengths compared droplets. also how evolves rising cloudy parcels atmosphere. as subsaturated air entrained into turbulently mixed with parcel, evaporation causes reduction droplet sizes, which leads corresponding increases per strength acidity. Increased acidity, turn, greatly accelerates kinetics formation. Our results provide key insights single cloud-droplet chemistry, suggesting entrainment may be an important process SOA real

Language: Английский

Citations

0
Dissecting cirrus clouds: navigating effects of turbulence on homogeneous ice formation DOI Creative Commons
B. Kärcher, Fabian Hoffmann, Adam B. Sokol

et al.

npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)

Published: April 5, 2025

Language: Английский

Citations

0
Droplet heterogeneous nucleation in a rapid expansion aerosol chamber DOI Creative Commons
Martin A. Erinin, C. Sagan,

Ilian Ahmed

et al.

Review of Scientific Instruments, Journal Year: 2025, Volume and Issue: 96(5)

Published: May 1, 2025

We present a new experimental facility to investigate the nucleation and growth of liquid droplets ice particles under controlled conditions characterize processes relevant cloud microphysics: rapid expansion aerosol chamber (REACh). REACh is an intermediate size (∼0.14 m3) combining principle with ability probe influence turbulent flows. Water droplet heterogeneous onto seeding aerosols achieved via sudden pressure drop accompanied by temperature drop, which can cause humid air condense into appropriate thermodynamic conditions. features tight control monitoring initial saturation ratio water vapor, identity concentration particles, temperature, pressure, flow mixing, together high speed real-time measurements number. Here, we demonstrate that minimum reached during each be reasonably described thermodynamics dry or moist adiabats for range relative humidities. The number formed overall lifetime are characterized as function vapor ratio. total scales linearly concentration, suggesting all injected serve condensation nuclei. While increases mean decreases result competition available vapor. Theoretical considerations provide quantitative prediction over repetition rate experiments perform will permit extensive characterization processes, including onset growth, importance turbulence fluctuations. leverage capabilities this explore wide physical parameters encompassing regimes microphysics.

Language: Английский

Citations

0
Dependence of Aerosol‐Droplet Partitioning on Turbulence in a Laboratory Cloud DOI
Abu Sayeed Shawon, Prasanth Prabhakaran, Greg Kinney

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2021, Volume and Issue: 126(5)

Published: Feb. 14, 2021

Abstract Activation is the first step in aerosol‐cloud interactions, which have been identified as one of principal uncertainties Earth's climate system. Aerosol particles become cloud droplets, or activate, when ambient saturation ratio exceeds a threshold, depends on particle's size and hygroscopicity. In traditional formulation process, only average, uniform ratios are considered. However, turbulent environments like clouds intrinsically fluctuations around mean values scalar fields temperature water vapor concentration, determine ratio. Through laboratory measurements, we show that these an important parameter needs to be addressed fully describe activation. Our results show, even for single‐sized, chemically homogeneous aerosols, blur correspondence between activation chemical composition, turbulence can increase fraction aerosol activated decreases monotonically concentration increases. Taken together, our data demonstrate effects equivalent limited updraft regimes, known from adiabatic parcel theory.

Language: Английский

Citations

23