气候变化领域集成服务门户(CCPortal): Precipitation-Radiation-Circulation Feedback Processes Associated with Structural Changes of the ITCZ in a Warming Climate during 1980-2014: An Observational Portrayal

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DOI	10.1175/JCLI-D-20-0068.1
	Precipitation-Radiation-Circulation Feedback Processes Associated with Structural Changes of the ITCZ in a Warming Climate during 1980-2014: An Observational Portrayal
	Lau W.K.M.; Tao W.
发表日期	2020
ISSN	0894-8755
起始页码	8737
结束页码	8749
卷号	33 期号:20
英文摘要	In this study, long-term structural changes in the intertropical convergence zone (ITCZ) and associated precipitation-radiation-circulation feedback processes are examined using multiple sources of reanalysis data for temperature, winds, moisture, and observed precipitation and outgoing longwave radiation (OLR) during 1980-2014. Consistent with CMIP5 climate model projections of the "deep tropical squeeze"under greenhouse warming, this period witnessed a warming and wetting (increased specific humidity) global trend, characterized by a narrowing of the ITCZ core with increased precipitation, coupled to widespread tropospheric drying (deficient relative humidity), increased OLR in the subtropics and midlatitudes, a widening of the descending branches of the Hadley circulation, and a poleward shift of the jet streams in both hemispheres. The widespread tropospheric drying stems from 1) a faster rate of increased saturated water vapor with warming, relative to the increase in ambient moisture due to convective and large-scale transport, and 2) enhanced anomalous subsidence, and low-level moisture divergence in the subtropics and midlatitudes. The long-term trend in enhanced precipitation (latent heating) in the ITCZ core region is strongly coupled to increasing OLR (radiative cooling to space) in the expanding dry zones, particularly over land regions in the subtropics and midlatitudes, arguably as a necessary condition for global thermodynamic energy balance. Analyses of the trend patterns in vertical profiles of p velocity, temperature, and relative humidity with respect to ITCZ precipitation rate and OLR reveal that the contrast between the wet and dry regions in the troposphere has been increasing globally, with the ITCZ core getting wetter and contracting, while the marginal convective and dry zones are getting drier and expanding. ©2020 American Meteorological Society.
英文关键词	Moisture; Radiative Cooling; Tropics; Troposphere; Greenhouse warming; Hadley circulation; Intertropical convergence zone; Large-scale transport; Outgoing longwave radiation; Precipitation rates; Specific humidity; Thermodynamic energy; Climate models; air temperature; atmospheric moisture; climate modeling; climate prediction; CMIP; cooling; Hadley cell; heating; intertropical convergence zone; jet stream; longwave radiation; precipitation (climatology); relative humidity; troposphere; wind
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/171143
作者单位	Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States; State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
推荐引用方式 GB/T 7714	Lau W.K.M.,Tao W.. Precipitation-Radiation-Circulation Feedback Processes Associated with Structural Changes of the ITCZ in a Warming Climate during 1980-2014: An Observational Portrayal[J],2020,33(20).
APA	Lau W.K.M.,&Tao W..(2020).Precipitation-Radiation-Circulation Feedback Processes Associated with Structural Changes of the ITCZ in a Warming Climate during 1980-2014: An Observational Portrayal.Journal of Climate,33(20).
MLA	Lau W.K.M.,et al."Precipitation-Radiation-Circulation Feedback Processes Associated with Structural Changes of the ITCZ in a Warming Climate during 1980-2014: An Observational Portrayal".Journal of Climate 33.20(2020).