CERTAINTY-ACI

Do we really know by how much ellipsoidal shapes enhance the extinction of solar radiation by dust?
By Obiso et al.

🔍 doi.org/10.5281/zeno...

What is the EC ESA Aerosol Cloud Cluster? YouTube video by CleanCloudProject

The EC-ESA Aerosol Cloud Cluster addresses the biggest uncertainty in regional climate prediction: aerosol-cloud interactions.
It unites +220 researchers linking EU projects CleanCloud & CERTAINTY with ESA’s AIRSENSE to advance climate modeling & mitigation
🔗 www.youtube.com/watch?v=CPHt...

Understanding Aerosol-Cloud Interactions is Pivotal for Improving Climate Predictions - Eos Global cooperation and knowledge sharing are essential to improve our understanding of cloud formation and evolution through aerosol-cloud interaction.

Our perspective paper on aerosol cloud interactions is featured in Eos.com as editor ‘s highlight 👇
@cleancloud-he.bsky.social
@certainty-aci.bsky.social

Understanding Aerosol-Cloud Interactions is Pivotal for Improving Climate Predictions eos.org/editor-highl...

[EC–ESA Aerosol Cloud Cluster Activity]

⁉️Uncertainty in how air pollution interacts with clouds is the largest source of uncertainty in near-term climate projections
🔍New policy brief explains why reducing the uncertainty is essential for effective climate policy certainty-aci.eu/policy-brief...

Aerosol‐Cloud Interactions: Overcoming a Barrier to Projecting Near‐Term Climate Evolution and Risk Aerosol-cloud interactions (ACI) remain a barrier to provide precise and actionable advice to policy makers at global and regional levels We recommend improving satellite retrievals, expanding gr...

Excited to announce our new publication on #aerosol #cloud #interactions 👇

Proud to lead this perspective with great experts from the field

@cleancloud-he.bsky.social
@certainty-aci.bsky.social
#ESA-AIRSENSE

agupubs.onlinelibrary.wiley.com/doi/full/10....

Aerosol‐Cloud Interactions: Overcoming a Barrier to Projecting Near‐Term Climate Evolution and Risk Aerosol-cloud interactions (ACI) remain a barrier to provide precise and actionable advice to policy makers at global and regional levels We recommend improving satellite retrievals, expanding gr...

[New EC-ESA Aerosol Cloud Cluster publication]

Aerosol-Cloud Interactions: Overcoming a Barrier to Projecting Near-Term Climate Evolution and Risk

By Im et al.

➡️ agupubs.onlinelibrary.wiley.com/doi/10.1029/...

@cleancloud-he.bsky.social

Diverse aerosol effects revealed during wildfire and dust storm events in Ukraine in April 2020 Aerosol particles are significant drivers of meteorological phenomena, especially during high concentration events such as wildfires and dust storms. …

📄🔥 Diverse aerosol effects revealed during wildfire and dust storm events in Ukraine in April 2020

✍️ Savenets, M., Mahura, A., Nuterman, R., Kulmala, M., Petäjä, T.

Atmospheric Pollution Research, 2026, 102906, ISSN 1309-1042
www.sciencedirect.com/science/arti...

Regional climate imprints of recent historical changes in anthropogenic Near Term Climate Forcers Abstract. Near-Term Climate Forcers (NTCFs) play a crucial role in shaping Earth's climate, yet their effects are often overshadowed by long-lived greenhouse gases (GHGs) when addressing climate varia...

📄New publication:
Regional climate imprints of recent historical changes in anthropogenic Near Term Climate Forcers

✍️ Santos-Espeso, A. et al.

➡️ esd.copernicus.org/articles/16/...
➡️ all CERTAINTY papers: certainty-aci.eu/publications/

Efficient ice multiplication from freezing raindrop fragmentation - Communications Earth & Environment Drop fragmentation upon freezing is an efficient secondary ice process, contributing to cloud ice formation even at relatively high temperatures, according to quantitative analyses of ice crystals via...

[Continuing collaboration with @cleancloud-he.bsky.social]

❄️ Efficient ice multiplication from freezing raindrop fragmentation

🖊️ Nils Pfeifer, Bernd Mom, Dmitri Moisseev, Susan Hartmann, Julian Meusel, Corinna Hoose & Maximilian Maahn

🔎 Read the publication: www.nature.com/articles/s43...

🌗☁️Aerosols have an uncertain climate impact because they interact with clouds in complex ways, especially stratocumulus. These clouds behave differently by day and night, yet a new analysis by Pugsley et al. shows that the key processes actually occur at night:

certainty-aci.eu/news-the-nig...

🇪🇺 🌎 Building Europe’s most ambitious joint effort to address one of the main knowledge gaps in climate science by advancing fundamental understanding of cloud–aerosol interactions

Last week CERTAINTY, @cleancloud-he.bsky.social & @esa.int funded projects including AIRSENSE joined forces in Lausanne

Secondary ice formation in cumulus congestus clouds: insights from observations and aerosol-aware large-eddy simulations Abstract. Secondary ice production (SIP) was investigated in a cumulus congestus system observed during the Secondary Production of Ice in Cumulus Experiment (SPICULE) campaign. Large-eddy simulations...

[New publication]

📃 Secondary ice formation in cumulus congestus clouds: insights from observations and aerosol-aware large-eddy simulations

✒️ @silviamcalderon.bsky.social et al.

➡️ Paper: acp.copernicus.org/articles/25/...
➡️ All CERTAINTY publications: certainty-aci.eu/publications/

Assessing the global contribution of marine aerosols, terrestrial bioaerosols, and desert dust to ice-nucleating particle concentrations Abstract. Aerosol–cloud interactions, particularly ice processes in mixed-phase clouds (MPCs), remain a key source of uncertainty in climate change assessments. This study introduces state-of-the-art ...

Assessing the global contribution of marine aerosols, terrestrial bioaerosols, and desert dust to ice-nucleating particle concentrations

✍️ Marios Chatziparaschos et al.

🔍 acp.copernicus.org/articles/25/...

Don’t miss Prof. Trude Storelvmo’s talk on Arctic mixed-phase #clouds, connecting insights from small-scale processses to large-scale #climate impacts. 🌍☁️
📆 Wednesday 29 Oct at 1pm (CET) on Zoom! epfl.zoom.us/j/6156668523...

Organic aerosol enhances boreal forest photosynthesis under cumulus clouds - Communications Earth & Environment Natural aerosols under cumulus clouds enhance diffuse radiation and therefore photosynthesis in boreal forests, increasing carbon uptake, according to analysis of atmospheric data from a forest site in southern Finland.

☁️ 🌲 Cumulus clouds amplify boreal forest photosynthesis

A recent study by Ezhova et al., based on long-term observations in Finland, shows that, in boreal forests, organic aerosols enhance photosynthesis under cumulus clouds.

🔍 www.nature.com/articles/s43...
🔍 certainty-aci.eu/news/

Large-scale impacts of the 2023 Canadian wildfires on the Northern Hemisphere atmosphere - npj Clean Air npj Clean Air - Large-scale impacts of the 2023 Canadian wildfires on the Northern Hemisphere atmosphere

🌎🔥Roșu et al. found that the 2023 Canadian wildfires emissions caused widespread increases in aerosol concentrations across the Northern Hemisphere, leading to a measurable cooling of surface air temperatures

🔍 certainty-aci.eu/news-climate...
🔍 www.nature.com/articles/s44...

Missed the great fireside chat with Gavin Pretor-Pinney & Edward Gryspeerdt on clouds? 🌥️

No worries, you can catch the replay here:
⬇️⬇️⬇️

🛳️ 🌎 Impacts of shipping fuel regulations on global warming

👉 Read the paper: www.nature.com/articles/s43... (Jianhao Zhang, Yao-Sheng Chen, Edward Gryspeerdt, Takanobu Yamaguchi & Graham Feingold)

👉 Discover more CERTAINTY web stories: certainty-aci.eu/news/

A recent study by Hermant, Huusko and Mauritsen shows that the direct radiative effect of aerosols has continued to strengthen, even as emissions declined, whereas the indirect effect has weakened in line with emissions.

🔍 Read a summary here: certainty-aci.eu/news-aerosol...

🚀 Coming up on 19 September 2025: a fireside chat on clouds and climate with Gavin Pretor-Pinney and Edward Gryspeerdt

🔗 Register now: luma.com/3wtgxi06

☁️ Clouds & Climate: A Fireside Chat with Gavin Pretor-Pinney & Ed Gryspeerdt

🗓️ 19 Sept.
🕔 17:00–18:00 (GMT+2)
📍 Online luma.com/3wtgxi06

A special online fireside chat exploring the wonder of clouds & their vital role in the Earth’s climate system, bridging science, beauty & public engagement

Weak influence of anthropogenic emissions on aerosol, cloud, and rain in the wet season of the Amazon rainforest Abstract. Anthropogenic emissions have been shown to affect new particle formation, aerosol concentrations, and clouds. Such effects vary with region, environmental conditions, and cloud types. In the...

[ 📣 New publication]

Weak influence of anthropogenic emissions on aerosol, cloud, and rain in the wet season of the Amazon rainforest

✒️ Wang, X., Carslaw, K. S., Grosvenor, D. P., and Gordon, H.

🔗 acp.copernicus.org/articles/25/...

🔎 All CERTAINTY papers: certainty-aci.eu/publications/

Large-scale impacts of the 2023 Canadian wildfires on the Northern Hemisphere atmosphere - npj Clean Air npj Clean Air - Large-scale impacts of the 2023 Canadian wildfires on the Northern Hemisphere atmosphere

📣 A new study examines the effects of the extreme 2023 Canadian wildfires using an Earth system model, comparing modelled atmospheric conditions with and without wildfire emissions.

✒️ Roșu et al.

🔎 www.nature.com/articles/s44...
🔎 All CERTAINTY publications: certainty-aci.eu/publications/

Organic aerosol enhances boreal forest photosynthesis under cumulus clouds - Communications Earth & Environment Natural aerosols under cumulus clouds enhance diffuse radiation and therefore photosynthesis in boreal forests, increasing carbon uptake, according to analysis of atmospheric data from a forest site i...

[ 📣 Summer 2025 - Publication]

Organic aerosol enhances boreal forest photosynthesis under cumulus clouds ☁️

✒️ by Ekaterina Ezhova et al.

🔗 Read the paper here: www.nature.com/articles/s43...

⏰ Join us tomorrow ⏰

📢 WEBINAR
Distinguishing aerosol-cloud interactions amidst cloud variability

🗨️ @harrikokkola.bsky.social

🗓️ Wednesday, Aug 27
🕐 13:00 CEST | 📍 Zoom: epfl.zoom.us/j/6156668523...

@cleancloud-he.bsky.social

Using a Machine Learning Approach for Isolating Aerosol Effects on Cloud Droplet Number Concentration in Marine Stratocumulus Clouds Elastic Net Regression effectively estimates cloud droplet response to aerosol changes from satellite data, despite multiple factors Traditional regression methods can misrepresent aerosol–cloud ...

[📣 August 2025 - New publication]

Excited to share our latest paper: "Using a Machine Learning Approach for Isolating Aerosol Effects on Cloud Droplet Number Concentration in Marine Stratocumulus Clouds" ☁️

✒️ by Muhammed Irfan et al.

🔗 agupubs.onlinelibrary.wiley.com/doi/10.1029/...

📢 Do not miss @cleancloud-he.bsky.social 's webinar with @harrikokkola.bsky.social

☁️ Distinguishing aerosol-cloud interactions amidst cloud variability

🗓️ Wednesday, Aug 27
🕐 13:00 CEST | 📍 Zoom: epfl.zoom.us/j/6156668523...

Image description: A crowded conference hall with attendees. With text reading:" The call for session proposals for #EGU26 is now open! Apply by September 16, 2025."

The call for #session #proposals for the #EGU26 General Assembly is now open!
Submit short course ideas and/or proposals for Union Symposia and Great Debates by 16 September 2025.

👉 Submit your proposals here: egu.eu/60GYS7

🆕 Publication - How to trace the origins of short-lived atmospheric species: an Arctic example

A recent study by Anderson Da Silva et al. validated an improved protocol to trace the origins of particles - Essential for precise climate modeling.

🔗 certainty-aci.eu/news-tracing...

Interested in how #aerosols, #clouds and their interactions are represented in state-of-the-art #models? Join our next seminar with Prof. Annica Ekman

📆 Wednesday 28 May at 1pm (CET) on Zoom and find out! epfl.zoom.us/j/6156668523...