DWD’s operational climate predictions – towards a seamless climate prediction website - towards a seamless climate prediction website

Abstract

Germany's National Meteorological Service, Deutscher Wetterdienst (DWD), is working on an operational seamless climate prediction approach: What started in 2016 with operational seasonal climate predictions, was later complemented with decadal climate predictions. Since 2022, DWD publishes decadal, seasonal, and subseasonal climate predictions on one single, comprehensive climate prediction website www.dwd.de/climatepredictions [1].While global simulations of decadal and seasonal predictions are produced by DWD’s climate prediction systems, global subseasonal predictions are retrieved from the European Centre of Medium-Range Weather Forecast (ECMWF). The next step in the operational processing chain is the empirical-statistical downscaling EPISODES [2], which results in high-resolution climate predictions (approx. 5 km) for Germany.Both global and regional climate predictions are evaluated using the Meteorological Analyzation and Visualization System MAVIS, a fork of the FREVA system (Free Evaluation System Framework for Earth System Modeling) [3]. We evaluate ensemble mean predictions using the Mean Squared Error Skill Score (MSESS) and the Pearson Correlation Coefficient. Probabilistic climate predictions are evaluated using the Ranked Probability Skill Score (RPSS).Ensemble mean and probabilistic climate prediction results of global and downscaled simulations, as well as the evaluation results are jointly published on DWD’s climate prediction website. The user-friendly graphical presentation is consistent for all displayed regions (global, Europe, Germany, and German cities) and across all time scales and was developed as a co-design between DWD and various national users.We work on several extensions of the website: multi-year seasonal predictions (e.g. 5-year summer means), the prediction of drought indices and El Nino Southern Oscillation predictions. In addition, a seamless time series combining observations, climate predictions and climate projections is in preparation. [1] A. Paxian, B. Mannig, M. Tivig, K. Reinhardt, K. Isensee, A. Pasternack, A. Hoff, K. Pankatz, S. Buchholz, S. Wehring, P. Lorenz, K. Fröhlich, F. Kreienkamp, B. Früh (2023). The DWD climate predictions website: towards a seamless outlook based on subseasonal, seasonal and decadal predictions. Manuscript in review.[2] Kreienkamp, F., Paxian, A., Früh, B., Lorenz, P., Matulla, C., 2018. Evaluation of the Empirical-Statistical Downscaling method EPISODES. Clim. Dyn. 52, 991–1026 (2019). https://doi.org/10.1007/s00382-018-4276-2.[3] Kadow, C., Illing, S., Lucio-Eceiza, E.E., Bergemann, M., Ramadoss, M., Sommer, P.S., Kunst, O., Schartner, T., Pankatz, K., Grieger, J., Schuster, M., Richling, A., Thiemann, H., Kirchner, I., Rust, H.W., Ludwig, T., Cubasch, U. and Ulbrich, U., 2021. Introduction to Freva – A Free Evaluation System Framework for Earth System Modeling. Journal of Open Research Software, 9(1), p.13. DOI: http://doi.org/10.5334/jors.253