气候变化领域集成服务门户(CCPortal): Dynamics and predictability of cold spells over the Eastern Mediterranean

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DOI	10.1007/s00382-020-05465-2
	Dynamics and predictability of cold spells over the Eastern Mediterranean
	Hochman A.; Scher S.; Quinting J.; Pinto J.G.; Messori G.
发表日期	2020
ISSN	0930-7575
英文摘要	The accurate prediction of extreme weather events is an important and challenging task, and has typically relied on numerical simulations of the atmosphere. Here, we combine insights from numerical forecasts with recent developments in dynamical systems theory, which describe atmospheric states in terms of their persistence (θ−1) and local dimension (d), and inform on how the atmosphere evolves to and from a given state of interest. These metrics are intuitively linked to the intrinsic predictability of the atmosphere: a highly persistent, low-dimensional state will be more predictable than a low-persistence, high-dimensional one. We argue that θ−1 and d, derived from reanalysis sea level pressure (SLP) and geopotential height (Z500) fields, can provide complementary predictive information for mid-latitude extreme weather events. Specifically, signatures of regional extreme weather events might be reflected in the dynamical systems metrics, even when the actual extreme is not well-simulated in numerical forecasting systems. We focus on cold spells in the Eastern Mediterranean, and particularly those associated with snow cover in Jerusalem. These rare events are systematically associated with Cyprus Lows, which are the dominant rain-bearing weather system in the region. In our analysis, we compare the ‘cold spell Cyprus Lows’ to other ‘regular’ Cyprus Low days. Significant differences are found between cold spells and ‘regular’ Cyprus Lows from a dynamical systems perspective. When considering SLP, the intrinsic predictability of cold spells is lowest hours before the onset of snow. We find that the cyclone’s location, depth and magnitude of air-sea fluxes play an important role in determining its intrinsic predictability. The dynamical systems metrics computed on Z500 display a different temporal evolution to their SLP counterparts, highlighting the different characteristics of the atmospheric flow at the different levels. We conclude that the dynamical systems approach, although sometimes challenging to interpret, can complement conventional numerical forecasts and forecast skill measures, such as model spread and absolute error. This methodology outlines an important avenue for future research, which can potentially be fruitfully applied to other regions and other types of weather extremes. © 2020, The Author(s).
英文关键词	Atmospheric dynamics; Chaos; Dynamical systems; Extreme temperatures; Extreme weather; Numerical weather prediction; Prediction; Weather forecasting
语种	英语
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/145700
作者单位	Department of Tropospheric Research, Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany; Department of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden; Department of Earth Sciences, Uppsala University, and Centre of Natural Hazards and Disaster Science (CNDS), Uppsala, Sweden
推荐引用方式 GB/T 7714	Hochman A.,Scher S.,Quinting J.,et al. Dynamics and predictability of cold spells over the Eastern Mediterranean[J],2020.
APA	Hochman A.,Scher S.,Quinting J.,Pinto J.G.,&Messori G..(2020).Dynamics and predictability of cold spells over the Eastern Mediterranean.Climate Dynamics.
MLA	Hochman A.,et al."Dynamics and predictability of cold spells over the Eastern Mediterranean".Climate Dynamics (2020).