• Energy Research

Abstract Weather and climate variations on subseasonal to decadal time scales can have enormous social, economic, and environmental impacts, making skillful predictions on these time scales a valuable tool for decision-makers. As such, there is a growing interest in the scientific, operational, and applications communities in developing forecasts to improve our foreknowledge of extreme events. On subseasonal to seasonal (S2S) time scales, these include high-impact meteorological events such as tropical cyclones, extratropical storms, floods, droughts, and heat and cold waves. On seasonal to decadal (S2D) time scales, while the focus broadly remains similar (e.g., on precipitation, surface and upper-ocean temperatures, and their effects on the probabilities of high-impact meteorological events), understanding the roles of internal variability and externally forced variability such as anthropogenic warming in forecasts also becomes important. The S2S and S2D communities share common scientific and technical challenges. These include forecast initialization and ensemble generation; initialization shock and drift; understanding the onset of model systematic errors; bias correction, calibration, and forecast quality assessment; model resolution; atmosphere–ocean coupling; sources and expectations for predictability; and linking research, operational forecasting, and end-user needs. In September 2018 a coordinated pair of international conferences, framed by the above challenges, was organized jointly by the World Climate Research Programme (WCRP) and the World Weather Research Programme (WWRP). These conferences surveyed the state of S2S and S2D prediction, ongoing research, and future needs, providing an ideal basis for synthesizing current and emerging developments in these areas that promise to enhance future operational services. This article provides such a synthesis.

Le Leeds Africa Climate Hackathon visait à générer des récits pertinents pour les utilisateurs sur le climat futur possible en Afrique de l'Est et de l'Ouest, pertinents pour la production d'énergie hydroélectrique et l'agriculture respectivement. Ici, nous discutons de la façon dont le hackathon virtuel a été organisé, présentons les résultats et examinons les leçons apprises en organisant un tel hackathon. Nous avons constaté que la production d'énergie hydroélectrique en Afrique de l'Est devra stocker plus d'eau pendant les épisodes de fortes pluies et faire face à des périodes de sécheresse plus longues à l'avenir. L'agriculture au Ghana sera confrontée à une possibilité beaucoup plus grande de sécheresses graves d'ici le milieu du siècle, en particulier si les objectifs de réchauffement climatique de 1,5 ° C ne sont pas atteints. El Leeds Africa Climate Hackathon tuvo como objetivo generar narrativas relevantes para el usuario sobre el posible clima futuro en África Oriental y Occidental relevante para la generación de energía hidroeléctrica y la agricultura, respectivamente. Aquí discutimos cómo se organizó el hackathon virtual, presentamos los resultados y examinamos las lecciones aprendidas al correr un hackathon de este tipo. Descubrimos que la generación de energía hidroeléctrica en el este de África necesitará almacenar más agua durante los eventos de lluvias más intensas y hacer frente a períodos de sequía más largos en el futuro. La agricultura en Ghana se enfrentará a una posibilidad mucho mayor de sequías graves a mediados de siglo, especialmente si no se cumplen los objetivos de calentamiento global de 1,5 grados centígrados. The Leeds Africa Climate Hackathon aimed to generate user-relevant narratives of possible future climate in East and West Africa relevant to hydroelectric power generation and agriculture respectively. Here we discuss how the virtual hackathon was organised, present the results, and examine the lessons learned from running such a hackathon. We found East African hydroelectric power generation will need to store more water during heavier rain events and cope with longer drought periods in future. Agriculture in Ghana will face a much greater possibility of severe droughts by mid-century especially if 1.5 degC global warming targets are not met. يهدف هاكاثون المناخ في ليدز إفريقيا إلى توليد روايات ذات صلة بالمستخدم عن المناخ المستقبلي المحتمل في شرق وغرب إفريقيا فيما يتعلق بتوليد الطاقة الكهرومائية والزراعة على التوالي. نناقش هنا كيفية تنظيم الهاكاثون الافتراضي، وتقديم النتائج، ودراسة الدروس المستفادة من تشغيل مثل هذا الهاكاثون. وجدنا أن توليد الطاقة الكهرومائية في شرق إفريقيا سيحتاج إلى تخزين المزيد من المياه خلال أحداث الأمطار الغزيرة والتعامل مع فترات الجفاف الأطول في المستقبل. ستواجه الزراعة في غانا احتمالًا أكبر بكثير للجفاف الشديد بحلول منتصف القرن خاصة إذا لم يتم تحقيق أهداف الاحترار العالمي عند 1.5 درجة مئوية.