气候变化领域集成服务门户(CCPortal): Identifying key driving mechanisms of heat waves in central Chile

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DOI	10.1007/s00382-021-05810-z
	Identifying key driving mechanisms of heat waves in central Chile
	Demortier A.; Bozkurt D.; Jacques-Coper M.
发表日期	2021
ISSN	0930-7575
起始页码	139
结束页码	153
英文摘要	This study explores the main drivers of heat wave (HW) events in central Chile using state-of-the-art reanalysis data (ERA5) and observations during the extended austral summer season (November to March) for the period 1979–2018. Frequency and intensity aspects of the HW events are considered using the total number of the HW events per season and the amplitude. We first contrast ERA5 with several surface meteorological stations in central Chile to evaluate its ability to capture daily maximum temperature variability and the HW events. We then use synoptic- and large-scale fields and teleconnection patterns to address the most favorable conditions of the HW events from a climatological perspective as well as from the extreme January 2017 HW event that swept central Chile with temperature records and wildfires. ERA5 tends to capture temperature extremes and the HW events at the inland stations; on the contrary, it has difficulties in capturing the maximum temperature variability at the coastal stations, which is plausible given the complex terrain features and confined coastal climate zone (only ∼ 7% of all grid boxes within central Chile). The composite HW days based on ERA5 reveals a mid-level trough-ridge dipole pattern exhibiting a blocking anticyclone on the surface over a large part of southwest South America. Relatively dry and warm easterly flow appears to accompany the anomalous warming in a large part of central Chile. The temporal evolution of the HW events yields a wave-like propagation pattern and enhancement of trough-ridge pattern along the South Pacific. This meridional dipole pattern is found to be largely associated with the Pacific South American pattern. In addition, the Madden–Julian Oscillation (MJO) appears to be a key component of the HW events in central Chile. In particular, while active MJO phases 2 and 7 promote sub-seasonal patterns that favor the South Pacific dipole mode, synoptic anomalies can superimpose on them and favor the formation of a migrating anticyclone over central-southern Chile and coastal lows over central Chile. Agreeing with the climatological findings, the extreme January 2017 HW analysis suggests that an eastward migratory mid-latitude trough-ridge pattern associated with MJO phase 2 was at work. We highlight that in addition to large- and synoptic-scale features, sub-synoptic processes such as coastal lows can have an important role in shaping the HW events and can lead to amplification of temperature extremes during the HW events. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Atmospheric teleconnections; Blocking pattern; Central Chile; Heat waves; MJO; Temperature extremes
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/183458
作者单位	École Nationale de la Météorologie, Toulouse, France; Departamento de Meteorología, Universidad de Valparaíso, Valparaíso, Chile; Centro de Estudios Atmosféricos y Astroestadística (CEAAS), Universidad de Valparaíso, Valparaíso, Chile; Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Universidad de Valparaíso, Valparaíso, Chile; Center for Climate and Resilience Research (CR)2, Santiago, Chile; Departamento de Geofísica, Universidad de Concepción, Concepción, Chile
推荐引用方式 GB/T 7714	Demortier A.,Bozkurt D.,Jacques-Coper M.. Identifying key driving mechanisms of heat waves in central Chile[J],2021.
APA	Demortier A.,Bozkurt D.,&Jacques-Coper M..(2021).Identifying key driving mechanisms of heat waves in central Chile.Climate Dynamics.
MLA	Demortier A.,et al."Identifying key driving mechanisms of heat waves in central Chile".Climate Dynamics (2021).