气候变化领域集成服务门户(CCPortal): The role of internal variability in climate change projections of North American surface air temperature and temperature extremes in CanESM2 large ensemble simulations

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DOI	10.1007/s00382-020-05296-1
	The role of internal variability in climate change projections of North American surface air temperature and temperature extremes in CanESM2 large ensemble simulations
	Yu B.; Li G.; Chen S.; Lin H.
发表日期	2020
ISSN	0930-7575
起始页码	869
结束页码	885
卷号	55
英文摘要	Recent studies indicated that the internal climate variability plays an important role in various aspects of projected climate changes on regional and local scales. Here we present results of the spreads in projected trends of wintertime North American surface air temperature and extremes indices of warm and cold days over the next half-century, by analyzing a 50-member large ensemble of climate simulations conducted with CanESM2. CanESM2 simulations confirm the important role of internal variability in projected surface temperature trends as demonstrated in previous studies. Yet the spread in North American warming trends in CanESM2 is generally smaller than those obtained from CCSM3 and ECHAM5 large ensemble simulations. Despite this, large spreads in the climate means as well as climate change trends of North American temperature extremes are apparent in CanESM2, especially in the projected cold day trends. The ensemble mean of forced climate simulations reveals high risks of warm days over the western coast and northern Canada, as well as a weakening belt of cold days extending from Alaska to the northeast US. The individual ensemble members differ from the ensemble mean mainly in magnitude of the warm day trends, but depart considerably from the ensemble mean in spatial pattern and magnitude of the cold day trends. The signal-to-noise ratio pattern of the warm day trend resembles that of the surface air temperature trend, with stronger signals over northern Canada, Alaska, and the southwestern US than the midsection of the continent. The projected cold day patterns reveal strong signals over the southwestern US, northern Canada, and the northeastern US. In addition, the internally generated components of mean and extreme temperature trends exhibit spatial coherences over North America, and are comparable to their externally forced trends. The large-scale atmospheric circulation-induced temperature variability influences these trends. Overall, our results suggest that climate change trends of North American temperature extremes are likely very uncertain and need to be applied with caution. © 2020, The Author(s).
语种	英语
scopus关键词	air temperature; climate change; computer simulation; ensemble forecasting; extreme event; regional climate; surface temperature; trend analysis; North America
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/145398
作者单位	Climate Research Division, Environment and Climate Change Canada, 4905 Dufferin Street, Toronto, ON M3H 5T4, Canada; Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; Meteorological Research Division, Environment and Climate Change Canada, Dorval, Canada
推荐引用方式 GB/T 7714	Yu B.,Li G.,Chen S.,et al. The role of internal variability in climate change projections of North American surface air temperature and temperature extremes in CanESM2 large ensemble simulations[J],2020,55.
APA	Yu B.,Li G.,Chen S.,&Lin H..(2020).The role of internal variability in climate change projections of North American surface air temperature and temperature extremes in CanESM2 large ensemble simulations.Climate Dynamics,55.
MLA	Yu B.,et al."The role of internal variability in climate change projections of North American surface air temperature and temperature extremes in CanESM2 large ensemble simulations".Climate Dynamics 55(2020).