Jiménez-Esteve B, Kornhuber K, Domeisen D I V
ETH Zürich Institute for Atmospheric and Climate Science Zürich Switzerland.
Earth Institute Columbia University New York NY USA.
Geophys Res Lett. 2022 Nov 16;49(21):e2021GL096337. doi: 10.1029/2021GL096337. Epub 2022 Nov 9.
Heatwaves are persistent temperature extremes associated with devastating impacts on human societies and ecosystems. In the midlatitudes, amplified quasi-stationary Rossby waves have been identified as a key mechanism for heatwave occurrence. Amplified waves with preferred longitudinal locations lead to concurrent extremes in specific locations. It is therefore important to identify the essential components in the climate system that contribute to phase-locking of wave patterns. Here, we investigate the role of dry atmospheric dynamics and topography in causing concurrent heatwaves by using an idealized general circulation model. Topography is included in the model experiments as a Gaussian mountain. Our results show that amplified Rossby waves exhibit clear phase-locking behavior and a decrease in the zonal phase speed when a large-scale localized topographic forcing is imposed, leading to concurrent heat extremes at preferred locations.
热浪是持续的极端温度，会对人类社会和生态系统造成毁灭性影响。在中纬度地区，增强的准静止罗斯贝波已被确认为热浪发生的关键机制。具有特定纵向位置的增强波会导致特定地点同时出现极端情况。因此，确定气候系统中导致波型锁相的关键要素非常重要。在此，我们使用理想化的大气环流模型研究干燥大气动力学和地形在引发同时出现的热浪中所起的作用。在模型实验中，地形以高斯山脉的形式呈现。我们的结果表明，当施加大规模局部地形强迫时，增强的罗斯贝波会表现出明显的锁相行为，纬向相速度降低，从而在特定地点导致同时出现极端高温。
