Periodic Reporting for period 1 - CERTAINTY (Cloud-aERosol inTeractions & their impActs IN The earth sYstem)
Periodo di rendicontazione: 2024-01-01 al 2025-06-30
Improved knowledge of clouds, aerosols, and their interactions is essential for better predictions of weather and climate. Aerosols (particles such as sea salt, dust, and other matter) can warm/cool the planet by reflecting/absorbing sunlight and altering cloud properties. Both the role of aerosols in climate and the way clouds respond to their presence remain major uncertainties in projections. This limits our ability to predict how global and regional climates, including extremes, will respond to rising greenhouse gases and how aerosols/clouds drive feedbacks.
Reducing these uncertainties is essential for reliable projections and weather prediction, supporting EU policy goals under the Green Deal, the EU Climate Law, and the Paris Agreement. CERTAINTY addresses this by combining Europe’s world-leading infrastructures, coordinated observation networks, and new satellite missions (EarthCARE, MetOp-SG) with advanced algorithms, machine learning, data assimilation, high-resolution and regional models, and state-of-the-art Earth system models.
The project targets key processes controlling aerosols, clouds, and their radiative effects—from warm and cold cloud microphysics to the aerosol lifecycle—across timescales from hours to decades. By integrating observation-based knowledge into models, CERTAINTY will improve understanding, enhance predictive skill, and deliver more accurate projections of climate trends and high-impact weather events.
Results will inform climate services and policy, contributing to the UN Sustainable Development Goals and supporting decisions for European citizens, industry, and governments, while keeping Europe at the forefront of climate science. This will be achieved through improved information and models of aerosols and clouds that underpin the IPCC and feed into European climate and weather services such as Copernicus.
Reducing these uncertainties is essential for reliable projections and weather prediction, supporting EU policy goals under the Green Deal, the EU Climate Law, and the Paris Agreement. CERTAINTY addresses this by combining Europe’s world-leading infrastructures, coordinated observation networks, and new satellite missions (EarthCARE, MetOp-SG) with advanced algorithms, machine learning, data assimilation, high-resolution and regional models, and state-of-the-art Earth system models.
The project targets key processes controlling aerosols, clouds, and their radiative effects—from warm and cold cloud microphysics to the aerosol lifecycle—across timescales from hours to decades. By integrating observation-based knowledge into models, CERTAINTY will improve understanding, enhance predictive skill, and deliver more accurate projections of climate trends and high-impact weather events.
Results will inform climate services and policy, contributing to the UN Sustainable Development Goals and supporting decisions for European citizens, industry, and governments, while keeping Europe at the forefront of climate science. This will be achieved through improved information and models of aerosols and clouds that underpin the IPCC and feed into European climate and weather services such as Copernicus.
CERTAINTY is an integrated European research effort to reduce uncertainties in aerosol-cloud-radiation interactions that combines laboratory studies, field campaigns, satellite remote sensing, and multi-scale modelling, supported by advanced algorithms, machine learning, and data assimilation.
Achievements include:
- New process understanding: Laboratory and observational studies have delivered improved descriptions of warm and cold cloud microphysics, with new parameterisations for ice nucleating particles, secondary ice production, and aerosol activation, now implemented in high-resolution and Earth system models.
- Advances in the aerosol lifecycle: We have provided updated emissions datasets, mineralogical dust characterisation, and improved modelling of natural and anthropogenic sources, refining global aerosol distributions.
- Improved precipitation representation: High-resolution modelling and observations have clarified links between aerosol properties, droplet growth, ice multiplication, and precipitation initiation in diverse cloud regimes.
- ARI and ACI impacts on weather and climate: The first global assimilation of all-sky visible radiances into ECMWF’s 4D-Var improves both analyses and forecasts of clouds in the Integrated Forecast System (IFS). Case studies using regional and global models show how aerosols modulate extreme precipitation and influence radiative forcing, with new schemes reducing Arctic temperature and cloud biases.
- Early exploitation of next-generation satellite data: The project has pioneered validation and use of EarthCARE, developing new dust optical properties, retrieval algorithms, and assimilation operators to enhance model evaluation and forecasting.
Through coordinated case studies, shared infrastructure, and interlinked work packages, CERTAINTY has delivered new parameterisations, model codes, and datasets (openly released under FAIR principles) already improving representation of aerosol-cloud interactions from cloud-resolving to Earth system scales.
Achievements include:
- New process understanding: Laboratory and observational studies have delivered improved descriptions of warm and cold cloud microphysics, with new parameterisations for ice nucleating particles, secondary ice production, and aerosol activation, now implemented in high-resolution and Earth system models.
- Advances in the aerosol lifecycle: We have provided updated emissions datasets, mineralogical dust characterisation, and improved modelling of natural and anthropogenic sources, refining global aerosol distributions.
- Improved precipitation representation: High-resolution modelling and observations have clarified links between aerosol properties, droplet growth, ice multiplication, and precipitation initiation in diverse cloud regimes.
- ARI and ACI impacts on weather and climate: The first global assimilation of all-sky visible radiances into ECMWF’s 4D-Var improves both analyses and forecasts of clouds in the Integrated Forecast System (IFS). Case studies using regional and global models show how aerosols modulate extreme precipitation and influence radiative forcing, with new schemes reducing Arctic temperature and cloud biases.
- Early exploitation of next-generation satellite data: The project has pioneered validation and use of EarthCARE, developing new dust optical properties, retrieval algorithms, and assimilation operators to enhance model evaluation and forecasting.
Through coordinated case studies, shared infrastructure, and interlinked work packages, CERTAINTY has delivered new parameterisations, model codes, and datasets (openly released under FAIR principles) already improving representation of aerosol-cloud interactions from cloud-resolving to Earth system scales.
CERTAINTY has delivered advances that move aerosol-cloud-radiation interaction (ACI) research beyond the current state of the art.
Examples of key achievements that are still in progress include:
- Novel parameterisations for cloud microphysics: We have developed and implemented machine-learning-based schemes for secondary ice production, species-specific dust ice-nucleating particle formulations, and next-generation cloud droplet activation models in high-resolution and Earth system models. These provide more realistic cloud-phase partitioning, reduce long-standing Arctic biases, and improve simulation of precipitation onset.
- Early adoption of EarthCARE capabilities: CERTAINTY has worked towards exploitation of lidar and radar products as available. CERTAINTY partners have been involved in the EarthCARE science team, directly contributing to EarthCARE Cal/Val activities, and preparation of tools and methods for the assimilation of EarthCARE in models.
- Integrated multi-scale case studies: Coordinated analysis of laboratory, in-situ, and remote sensing observations with modelling across scales is producing the first directly comparable datasets and process constraints for ACI in diverse environments, from the Arctic to the tropics.
These results work towards improved knowledge of climate and weather, with direct implications for services and policy. To ensure uptake and sustained impact, continued investment is needed in:
- Sustained investment of atmospheric science at the European level to lead the world in climate and weather science to support evidence based policy decisions.
- Long-term observational networks and campaign data integration to maintain and expand process-level constraints.
- Model development and evaluation cycles that incorporate and test new schemes in operational forecasting and climate modelling frameworks.
- Open science infrastructures to provide wide access to model codes, datasets, and algorithms, supporting both research and climate service applications.
- European and international collaboration to harmonise approaches and facilitate integration into global/European initiatives including such as CMIP7, IPCC assessments, and Copernicus services.
Examples of key achievements that are still in progress include:
- Novel parameterisations for cloud microphysics: We have developed and implemented machine-learning-based schemes for secondary ice production, species-specific dust ice-nucleating particle formulations, and next-generation cloud droplet activation models in high-resolution and Earth system models. These provide more realistic cloud-phase partitioning, reduce long-standing Arctic biases, and improve simulation of precipitation onset.
- Early adoption of EarthCARE capabilities: CERTAINTY has worked towards exploitation of lidar and radar products as available. CERTAINTY partners have been involved in the EarthCARE science team, directly contributing to EarthCARE Cal/Val activities, and preparation of tools and methods for the assimilation of EarthCARE in models.
- Integrated multi-scale case studies: Coordinated analysis of laboratory, in-situ, and remote sensing observations with modelling across scales is producing the first directly comparable datasets and process constraints for ACI in diverse environments, from the Arctic to the tropics.
These results work towards improved knowledge of climate and weather, with direct implications for services and policy. To ensure uptake and sustained impact, continued investment is needed in:
- Sustained investment of atmospheric science at the European level to lead the world in climate and weather science to support evidence based policy decisions.
- Long-term observational networks and campaign data integration to maintain and expand process-level constraints.
- Model development and evaluation cycles that incorporate and test new schemes in operational forecasting and climate modelling frameworks.
- Open science infrastructures to provide wide access to model codes, datasets, and algorithms, supporting both research and climate service applications.
- European and international collaboration to harmonise approaches and facilitate integration into global/European initiatives including such as CMIP7, IPCC assessments, and Copernicus services.