Windows of Opportunity for Skillful Forecasts Subseasonal to Seasonal and Beyond

There is high demand and a growing expectation for predictions of environmental conditions that go beyond 0-14 day weather forecasts with outlooks extending to one or more seasons and beyond. This is driven by the needs of the energy, water management, and agriculture sectors, to name a few. There is an increasing realization that, unlike weather forecasts, prediction skill on longer timescales can leverage specific climate phenomena or conditions for a predictable signal above the weather noise. Currently, it is understood that these conditions are intermittent in time and have spatially heterogeneous impacts on skill, hence providing strategic windows of opportunity for skillful forecasts. Research points to such windows of opportunity, including El Niño or La Niña events, active periods of the Madden-Julian Oscillation, disruptions of the stratospheric polar vortex, when certain large-scale atmospheric regimes are in place, or when persistent anomalies occur in the ocean or land surface. Gains could be obtained by increasingly developing prediction tools and metrics that strategically target these specific windows of opportunity. Across the globe, re-evaluating forecasts in this manner could find value in forecasts previously discarded as not skillful. Users’ expectations for prediction skill could be more adequately met, as they are better aware of when and where to expect skill and if the prediction is actionable. Given that there is still untapped potential, in terms of process understanding and prediction methodologies, it is safe to expect that in the future forecast opportunities will expand. Process research and the development of innovative methodologies will aid such progress.

对超越0-14天天气预报范畴、展望期延伸至一个或多个季节乃至更长期限的环境条件预测，存在着极高的需求与日益增长的期待。这一需求由能源、水资源管理及农业等行业的需求驱动（仅举几例）。人们逐渐认识到，与天气预报不同，更长时间尺度的预测能力可借助特定气候现象或条件，获取超越天气噪声的可预测信号。当前研究表明，这些条件在时间上具有间歇性，且对预测能力的影响存在空间异质性，因此为高技能预测提供了战略性机会窗口。相关研究指出此类机会窗口包括厄尔尼诺（El Niño）或拉尼娜（La Niña）事件、马登-朱利安振荡（Madden-Julian Oscillation）活跃期、平流层极涡（stratospheric polar vortex）中断、特定大尺度大气模态存在时，或海洋与陆地表面出现持续异常的情况。通过持续开发针对这些特定机会窗口的预测工具与指标，有望获得显著收益。在全球范围内，以这种方式重新评估预测结果，可挖掘出此前因被认为缺乏预测技能而遭舍弃的预测数据的价值。用户对预测技能的期望将得到更充分的满足，因为他们能更好地了解何时何地可获得高技能预测，以及预测结果是否具备可操作性。鉴于在过程理解与预测方法学领域仍存在未开发的潜力，可以确信未来的预测机会将进一步拓展。过程研究与创新方法学的发展将助力这一进步。