European Centre for Medium-Range Weather Forecasts

Optical properties and shape-dependent retrievals of the imaginary part of the refractive index of freshly emitted Saharan dust

Abstract. Mineral dust is a major contributor to atmospheric aerosols and plays a complex role in Earth’s radiation budget. However, large uncertainties remain in quantifying its direct radiative effects (DRE), primarily due to poorly constrained absorption properties. Most estim...

The Mediterranean Extreme Events Experiment and storm Harry in January 2026

Abstract The Global Observing System (GOS) includes drifting buoys with barometers whose surface pressure observations are essential for estimating the current state of the atmosphere and ocean for Numerical Weather Prediction. The Global Drifter Program, a scientific project bas...

A simplified isoprene oxidation mechanism for fast formaldehyde-based emission inversion of isoprene

We introduce the Simplified Isoprene Chemistry for MAGRITTE (SICMA), a compact chemical mechanism designed for computationally efficient global chemistry transport modeling of formaldehyde (HCHO) and adjoint-based emission inversions. The scheme reduces the isoprene oxidation net...

Benchmarking Core-Level X-ray Absorption with MRSF-TDDFT, RASPT2, and Stochastic GAS Using the XABOOM Set

Abstract Rapid advances in X-ray free-electron laser facilities are producing X-ray absorption spectra (XAS) with unprecedented detail, creating a pressing need for theoretical methods that are both accurate and computationally efficient to interpret subtle spectral features. In...

Dry snow initialization and densification over the Greenland and Antarctic ice sheets in the ORCHIDEE land surface model

Abstract. Accurate modeling of the snowpack over ice sheets is essential for quantifying their surface mass balance contribution and their resulting impact on sea level rise. The snowpack evolution is largely governed by surface climate but also by internal processes such as dens...

The impact of stochastic sea ice perturbations on seasonal forecasts

Abstract. Sea ice ensemble forecasts can be highly underdispersive, meaning that the ensemble spread is notably lower than the average forecast error. One common strategy to address underdispersion is to add stochastic perturbations to the forecasts. We detail the implementation...

How Good Is Your Forecast? The Importance of User‐Centred, Decision‐Relevant Evaluation of Forecasts and Climate Services

ABSTRACT Forecasts and climate services, spanning weather and climate timescales, play a vital role in supporting short‐ and long‐term decision‐making across a wide range of climate‐sensitive sectors. Understanding their skill is crucial to ensuring that the information provided...

On the reliability of seasonal snow forecasts

Abstract. Reliable information on seasonal snow conditions is important for long-range weather forecasting and climate modeling. The reliability of winter-mean hindcasts of snow water equivalent (SWE) produced by the ECMWF for the period 1993–2022 within the CopERnIcus climate ch...

Using microwave imager observations to improve the ocean temperature in a coupled NWP system

Abstract Knowledge of the ocean temperature is vital to the accurate use of satellite radiances in weather forecasting and it helps improve the quality of forecasts for the ocean and atmosphere. A recent upgrade to the European Centre for Medium‐Range Weather Forecasts (ECMWF) In...