The European Centre for Medium-Range Weather Forecasts (ECMWF) has achieved a significant milestone by integrating new cloud radar data from the EarthCARE mission, a collaborative effort between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA), into its global forecasting system. This marks the first-ever operational assimilation of cloud radar observations within a weather forecasting center, an advancement that promises to sharply reduce uncertainties in weather predictions related to cloud dynamics. By enhancing the ability to observe the vertical structure of clouds worldwide, EarthCARE’s cloud profiling radar data enriches the forecasting model with unprecedented detail, setting a new standard in meteorological science.
Clouds have long posed a significant challenge to weather forecasters due to their complex and transient nature, which impacts atmospheric conditions and, consequently, weather systems in intricate ways. Conventional remote sensing techniques have provided information on cloud location and some integrated properties; however, EarthCARE’s radar data breaks new ground by delivering detailed vertical profiles of cloud composition and microphysical properties. This includes the ability to distinguish between ice and liquid phases within clouds, quantify water mass, estimate average particle size, and measure particle fall speeds, which are critical parameters for improving the physical representation of clouds in forecasting models.
Unlike earlier satellite observations that relied primarily on microwave imagers and sounders providing limited vertical resolutions, EarthCARE’s Cloud Profiling Radar (CPR) adds a vital three-dimensional perspective. This radar not only identifies where clouds and precipitation occur but also reveals their internal structures and dynamic behaviors over time. ECMWF’s Integrated Forecasting System (IFS) capitalizes on these capabilities, integrating the data to refine short- to medium-range weather forecasts globally. The assimilation process merges these radar observations with existing model forecasts using sophisticated data assimilation techniques to produce the most accurate initial state of the atmosphere possible.
The integration of EarthCARE radar data represents years of meticulous collaboration among ESA, JAXA, ECMWF, and other partners including the Royal Netherlands Meteorological Institute (KNMI) and McGill University. ECMWF scientists worked closely with engineers and mission teams to ensure optimal data quality and operational readiness of the assimilation framework. The radar observations arrive every 90 minutes from EarthCARE’s orbit, effectively providing a near-real-time vertical snapshot of cloud conditions that was previously unattainable from spaceborne instruments.
An exemplary demonstration of EarthCARE’s capabilities occurred in September 2025 when the satellite directly overflew Hurricane Humberto’s eye. It captured detailed measurements of vertical wind, rain, and snow motions within the hurricane’s eyewall — data never before seen from space at such resolution. This breakthrough offers scientists an unparalleled window into the inner workings of extreme weather systems, enabling new insights into hurricane dynamics and the complex interplay of atmospheric processes driving storm intensity and structure.
These enhanced observations are fueling improvements in ECMWF’s weather models by providing a stringent test of cloud microphysics parameterizations. Scientists can directly compare observed radar Doppler velocities, particle sizes, and hydrometeor phases against simulated variables within the IFS, identifying where models successfully capture cloud processes and where refinements are necessary. This feedback loop accelerates progress toward more realistic forecasts, directly contributing to improved public safety through better prediction of weather hazards.
Owning the capability to simulate EarthCARE observations within the ECMWF model also facilitates continuous monitoring of the satellite’s radar and lidar instrument performance. Shortly after the instruments were activated, ECMWF began near-real-time quality assessments, providing critical feedback to ESA and JAXA calibration teams. Such close cooperation ensures that data streams remain accurate and reliable, an essential aspect for sustained operational use and scientific exploitation.
The Doppler radar on EarthCARE represents a paradigm shift for cloud physics research as it not only locates hydrometeors but measures their fall speeds, offering direct insight into microphysical processes within clouds such as aggregation, melting, and evaporation. This has profound implications for refining the representation of precipitation formation and evolution in weather models, processes traditionally hampered by limited observational constraints.
Beyond immediate forecasting improvements, the assimilation of EarthCARE data holds promise for enhancing climate models. Improved understanding of cloud microphysics and dynamics helps constrain uncertainty in how cloud feedbacks influence global climate sensitivity. Hence, EarthCARE’s impact extends well beyond weather prediction, feeding into the broader scientific endeavor to characterize and predict climate variability and change.
JAXA’s EarthCARE Mission Scientist Takuji Kubota underlined the societal benefits of this international collaboration by highlighting advances in forecasting accuracy for extreme events such as typhoons and heavy precipitation. Enhanced early warning capabilities stemming from this work have the potential to mitigate the impacts of natural disasters, safeguarding lives and property not just in Europe and Japan but worldwide.
In summary, the operational use of EarthCARE’s cloud radar data within ECMWF’s IFS marks a transformative advancement in atmospheric science. By unlocking vertical cloud structure information at unprecedented resolution, meteorologists now have a powerful new tool to improve the skill of weather forecasts and enrich scientific understanding of cloud-related processes. This breakthrough exemplifies the extraordinary benefits of international scientific cooperation and promises to drive both forecast and climate modeling innovations for years to come.
Subject of Research: Meteorology, Atmospheric Science, Cloud Microphysics and Weather Forecasting
Article Title: EarthCARE Satellite’s Cloud Radar Enhances Global Weather Forecasting with Vertical Cloud Profile Assimilation
News Publication Date: Not specified
Web References: https://www.ecmwf.int/en/about/media-centre/science-blog/2025/earthcare-hurricane-physics
Image Credits: ESA/JAXA/ECMWF
Keywords: EarthCARE, ESA, JAXA, ECMWF, cloud radar, weather forecasting, cloud microphysics, Doppler radar, hurricane observations, data assimilation, atmospheric science, Integrated Forecasting System
