European heat waves result from large-scale stationary waves and have major impacts on the economy and mortality. However, the dynamical processes leading to and maintaining heat waves are still not well understood. Here we use a nonlinear stationary wave model (NSWM) to examine the role played by anomalous stationary waves and how they are forced during heat waves. For our study, we use the Japanese Reanalysis (JRA-55) data for the period 1958 through 2017. We show that the NSWM can successfully reproduce the main features of the observed anomalous stationary waves in the upper troposphere. Our results indicate that the dynamics of heat waves are nonlinear, and transient momentum fluxes are the primary drivers of the observed anomalous stationary waves. The contribution from orographic forcing is moderate and mainly through nonlinear interactions with diabatic heating. Further decomposition of the transients indicates that the high-frequency transient vorticity fluxes make dominant contributions. Furthermore, our results reveal that the response to heating located in the tropical Indian Ocean and the west Pacific region is primarily responsible for maintaining the observed anomalous stationary waves linked to European heat waves. This is confirmed by exploring the relationship between heat waves and the Indian Ocean Dipole strength. The heating in the mid-latitude and tropical Atlantic region plays a secondary role. Our results suggest that European heat waves are potentially predictable by considering the nonlinear effects involved in anomalous stationary waves and the heating sources in the nearby and remote tropical region.

欧洲的热浪源于大规模的固定波浪，对经济和死亡率产生重大影响。但是，导致和保持热波的动力学过程仍未得到很好的理解。在这里，我们使用非线性平稳波模型（NSWM）来检查异常平稳波所起的作用以及在热浪期间它们是如何被强迫的。在我们的研究中，我们使用了1958年至2017年的日本再分析（JRA-55）数据。结果表明，NSWM可以成功重现对流层上层观测到的异常平稳波的主要特征。我们的结果表明，热波的动力学是非线性的，瞬态动量通量是观测到的异常平稳波的主要驱动因素。地形强迫的贡献是中等的，主要是通过与非绝热加热的非线性相互作用。瞬变的进一步分解表明，高频瞬变涡通量起主要作用。此外，我们的结果表明，热带印度洋和西太平洋地区对加热的响应主要负责维持与欧洲热浪有关的观测到的异常固定波。通过研究热波与印度洋偶极子强度之间的关系可以证实这一点。中纬度和热带大西洋地区的加热起次要作用。