气候变化领域集成服务门户(CCPortal): The role of latent heating in atmospheric blocking dynamics: a global climatology

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DOI	10.1007/s00382-019-04919-6
	The role of latent heating in atmospheric blocking dynamics: a global climatology
	Steinfeld D.; Pfahl S.
发表日期	2019
ISSN	0930-7575
起始页码	6159
结束页码	6180
卷号	53 期号:2020-09-10
英文摘要	Atmospheric blocking represents an important aspect of the mid-latitude weather variability, but the different processes contributing to its formation and maintenance are not yet fully understood. This study investigates the role that diabatic processes, in particular the release of latent heating in strongly ascending airstreams, play in the dynamics and spatio-temporal variability of blocking in a detailed 38-year global climatological analysis. The results show that the formation and (re-)intensification of blocking are often preceded by latent heating connected to upstream baroclinic developments. While the importance of latent heating varies considerably between individual blocking events and different regions, in particular between ocean and continents, latent heating is generally most important during onset and in more intense and larger blocks. The episodic nature of latent heating during the blocking life cycle, associated with a series of transient cyclones approaching the blocking, can contribute to both the high- (fast onset and fluctuation in intensity and size) and low-frequency (maintenance and quasi-stationarity during maturation phase) properties of blocking anticyclones and provide the required flow amplification in addition to dry-dynamical interaction between synoptic eddies and blocking. This amplification results from a combination of the direct injection of anticyclonic air into the upper-troposphere within cross-isentropic ascending airstreams, setting up large-scale anticyclonic PV anomalies, and the advection of PV by the enhanced divergent outflow at the tropopause (indirect effect). This divergent outflow on the western flank of the blocking anticyclone interacts with the upper-level PV gradient and leads to a westward amplification of the ridge, diminishing the tendency for dissipation and the eastward advection by the background flow, thus contributing to blocking stationarity. Taking into account such diabatic mechanisms in blocking dynamics will be important to improve predictions of blocking and assess future changes in the extratropical large-scale circulation. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Atmospheric blocking; Atmospheric dynamics; Climatology; Diabatic processes; Extratropical cyclones; Latent heating
语种	英语
scopus关键词	anticyclone; atmospheric dynamics; baroclinic mode; climate modeling; climatology; latent heat flux; regional climate; tropical cyclone; troposphere
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/145871
作者单位	Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland; Institute of Meteorology, Freie Universität Berlin, Berlin, Germany
推荐引用方式 GB/T 7714	Steinfeld D.,Pfahl S.. The role of latent heating in atmospheric blocking dynamics: a global climatology[J],2019,53(2020-09-10).
APA	Steinfeld D.,&Pfahl S..(2019).The role of latent heating in atmospheric blocking dynamics: a global climatology.Climate Dynamics,53(2020-09-10).
MLA	Steinfeld D.,et al."The role of latent heating in atmospheric blocking dynamics: a global climatology".Climate Dynamics 53.2020-09-10(2019).