气候变化领域集成服务门户(CCPortal): Effect of the north pacific tropospheric waveguide on the fidelity of model El Niño teleconnections

CCPortal

DOI	10.1175/JCLI-D-19-0156.1
	Effect of the north pacific tropospheric waveguide on the fidelity of model El Niño teleconnections
	Li R.K.K.; Woollings T.; O’Reilly C.; Scaife A.A.
发表日期	2020
ISSN	0894-8755
起始页码	5223
结束页码	5237
卷号	33 期号:12
英文摘要	In a free-running climate model, DJF tropical–extratropical teleconnections are assessed and compared to observed teleconnections in reanalysis data. From reanalysis, the leading mode of covariability between tropical outgoing longwave radiation (OLR) and Northern Hemisphere extratropical geopotential height (Z500) is identified using maximum covariance analysis (MCA). This mode relates closely to the El Niño pattern. The GCM captures the tropical OLR well but the associated extratropical Z500 less well. The GCM climatology has an equatorward shifted North Pacific jet bias. We examine whether the difference in the teleconnection pattern is related to the GCM’s jet bias. In both a ray-tracing analysis and a barotropic model, this jet bias is shown to affect the Rossby wave propagation from the tropical Pacific into the North Pacific. These idealized model results suggest qualitatively that the MCA difference is largely consistent with linear Rossby wave dynamics. While the basic state has a larger effect on the North Pacific MCA, a Rossby wave source (RWS) bias in the Caribbean has a larger effect on the North Atlantic MCA. The North Pacific jet bias is also proposed to affect the downstream propagation of waves from North America into the Caribbean, where it affects tropical RWS and the triggering of secondary waves into the North Atlantic. We propose that climatological biases in the tropics are one underlying cause of the jet bias. Our study may also help understand the results of other climate models with similar jet biases. © 2020 American Meteorological Society.
英文关键词	Mechanical waves; Tropics; Wave propagation; Barotropic models; Geo-potential heights; Maximum covariance analysis; Northern Hemispheres; Outgoing longwave radiation; Propagation of waves; ROSSBY wave propagation; Teleconnection patterns; Climate models; atmospheric wave; climate modeling; covariance analysis; El Nino; geopotential; jet; longwave radiation; teleconnection; troposphere; Pacific Ocean; Pacific Ocean (North)
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171299
作者单位	Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, United Kingdom; Met Office Hadley Centre, and College of Engineering, Mathematics and Physical Sciences, Exeter University, Exeter, United Kingdom
推荐引用方式 GB/T 7714	Li R.K.K.,Woollings T.,O’Reilly C.,et al. Effect of the north pacific tropospheric waveguide on the fidelity of model El Niño teleconnections[J],2020,33(12).
APA	Li R.K.K.,Woollings T.,O’Reilly C.,&Scaife A.A..(2020).Effect of the north pacific tropospheric waveguide on the fidelity of model El Niño teleconnections.Journal of Climate,33(12).
MLA	Li R.K.K.,et al."Effect of the north pacific tropospheric waveguide on the fidelity of model El Niño teleconnections".Journal of Climate 33.12(2020).