Observing Aerosols: New perspectives and implications for global modelling
Overview
In 2024, HARP2 and SPEXone instruments were launched on the PACE satellite and in 2025, Metop-SG successfully made it into orbit with the 3MI instrument onboard. These instruments are all polarimeters, capable of observing the polarization state of light scattered by the atmosphere and surface and providing detailed information about aerosols and cloud particles. Polarimeters have been used in space before, but the higher polarimetric accuracy, spectral range, number of viewing angles and improved spatial resolution mean that these new instruments are more accurately able to observe particle size, absorption properties, refractive index and aerosol type.
Polarimeters are not the only recently launched instruments to offer a new perspective on aerosols. EarthCARE has been providing operational observations since early 2025 that give a more accurate and updated understanding of the vertical structure of aerosols in the atmosphere. The potential of fundamentally changing the way aerosol observations are used in models has also started to be investigated, with research into all-sky visible reflectance and lidar extinction assimilation to jointly inform on aerosols and clouds.
In this 16th meeting of the International Cooperative for Aerosol Prediction (ICAP), the focus is on how these new observations or methodologies can be used to add value to global aerosol models. In particular, how the additional information on particle size, absorption, type and vertical structure can be utilised by models that rely on different aerosol and cloud assumptions than retrievals or direct observations.
What is ICAP?
The International Cooperative for Aerosol Prediction is a grassroots community of people who work in operational global aerosol prediction and monitoring. The ICAP meetings are functional operational workshops used to discuss best practices and find optimal common solutions to challenges, as well as to plan and coordinate global operational aerosol forecasting activities.
Attendance
Meetings and presentations are by invitation only by core member organisations and their operational partners. Applications are also received for a limited number of observers who have a direct stake in the proceedings. If you believe an appropriate invitation has been overlooked or wish to apply for observer status, please contact the meeting organisers or a core member for sponsorship. Core modeling development organizations include: BSC, ECMWF, JMA, NASA GMAO, NOAA NCEP, NRL, UKMO, MétéoFrance and FMI. Core remote sensing partners are from ESA, EUMETSAT, JAXA, and NASA.
Even though this workshop is open to core member organisations and invited speakers only, the presentations will be made available publicly shortly after the meeting.