2026/01/30 by Brian C. Rakoczy, David H. Bromwich, Sheng-Hung Wang · 1 voice
Earth and Planetary Sciences · Environmental Science · #Cryospheric studies and observations #Meteorological Phenomena and Simulations #Climate variability and models
paper · doi:10.1175/jcli-d-25-0215.1
openalex publication_date 2026/01/30 · openalex created_date 2026/02/01 · openalex updated_date 2026/06/26
Abstract The fifth generation European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5) is often used to support Antarctic climate research and as a primary training dataset for machine learning weather forecast models, making understanding its strengths and weaknesses essential. To quantify any potential biases and errors within the reanalysis, an evaluation is conducted by examining ERA5’s ability to represent the Antarctic near-surface wind regime, focusing on spatial patterns, seasonal variability, and long-term wind speed anomaly (WSA) trends. A continentwide, terrain-stratified comparison of over 100 in situ observations from automatic weather station (AWS) and staffed station records at 3-hourly resolution is conducted. We find that ERA5 represents winds well over expansive flat terrain such as the Ross Ice Shelf. In coastal and mountainous regions, ERA5 underestimates wind speeds, with negative biases exceeding 1.6 m s −1 and root-mean-square error (RMSE) values up to 4.4 m s −1 . Over the Antarctic Plateau, it overestimates winter wind speeds by up to 0.8 m s −1 . Probability distributions reveal an underestimation of the frequency of high wind events (>12 m s −1 ) across all terrain classes. WSA trend examination indicates significant spatial variability with positive trends over Ellsworth Land that can be linked to large-scale climate drivers including the Southern Annular Mode (SAM). Discrepancies exist between ERA5 and observation trends, indicating limitations in capturing localized variability. A comparison of ERA5 to the Antarctic Mesoscale Prediction System (AMPS) highlights the impact of higher-resolution representation of the near-surface winds, emphasizing the need for continued improvements in reanalysis datasets to enhance the representation of the Antarctic climate. Significance Statement An accurate historical representation of Antarctic near-surface winds is important for assessing climate variability and improving weather prediction systems. This study evaluated the fifth generation European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5) across the Antarctic mainland using over 100 long-term in situ records at 3-hourly resolution. ERA5 captures large-scale wind patterns effectively but consistently underestimates wind speeds in coastal and mountainous regions and overestimates winter winds over the high-elevation Antarctic Plateau. It also underrepresents the frequency of high wind events and often fails to match observed long-term variability at station scale. These limitations stem from spatial resolution constraints. As ERA5 is vital for Antarctic climate studies and serves as training data for artificial intelligence forecasting systems, uncorrected biases risk propagating errors. Improving resolution, bias-correction methods, and expanding observational networks would help enhance future climate research and forecasts.