The Impact of Tropical/Extratropical Interaction on Atmospheric Teleconnections

本项目旨在通过理想化数值模式实验和诊断分析，提高对驱动热带/温带相互作用的基本动力过程的理解。加强对热带/温带相互作用的了解对于改善中期（1-4周）天气预报至关重要。最近的研究表明，活跃的热带麦登-朱利安涛动（MJO）的不同阶段在1-4周后被北半球主要的遥相关型（北大西洋涛动和太平洋/北美模式）激发，并且与这些遥相关型发生频率的大变化相吻合。研究发现，基于MJO和厄尔尼诺-南方涛动阶段的概率天气预报，在提前2至4周的情况下，优于北美最先进的数值天气预报模式。在活跃的MJO之后，甚至观察到北极地表气温的变化。

This project has the goal of improving understanding of the basic dynamical processes that drive tropical/extratropical interaction on the intraseasonal time by performing both idealized numerical model experiments and diagnostic analyses. Enhanced understanding of tropical/extratropical interaction is crucial for improving medium range (1-4 week) weather forecasts. Recent studies have shown that different phases of an active tropical Madden-Julian Oscillation (MJO) are followed 1-4 weeks later by the excitation of the dominant Northern Hemisphere teleconnection patterns (both the North Atlantic Oscillation and the Pacific/North American patterns), and coincide with large changes in the frequency of occurrence of these teleconnection patterns. It has been found that probabilistic weather forecasts based on both MJO and El-Nino-Southern-Oscillation phases outperform state-of-the-art numerical weather prediction models for North America with lead times of 2 to 4 weeks. Changes to Arctic surface air temperature have even been observed following an active MJO.