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DOI	10.1175/JCLI-D-19-0046.1
	Trends in upper-tropospheric humidity: Expansion of the subtropical dry zones?
	Tivig M.; Grützun V.; John V.O.; Buehler S.A.
发表日期	2020
ISSN	0894-8755
起始页码	2149
结束页码	2161
卷号	33 期号:6
英文摘要	Subtropical dry zones, located in the Hadley cells’ subsidence regions, strongly influence regional climate as well as outgoing longwave radiation. Changes in these dry zones could have significant impact on surface climate as well as on the atmospheric energy budget. This study investigates the behavior of upper-tropospheric dry zones in a changing climate, using the variable upper-tropospheric humidity (UTH), calculated from climate model experiment output as well as from radiances measured with satellite-based sensors. The global UTH distribution shows that dry zones form a belt in the subtropical winter hemisphere. In the summer hemisphere they concentrate over the eastern ocean basins, where the descent regions of the subtropical anticyclones are located. Recent studies with model and satellite data have found tendencies of increasing dryness at the poleward edges of the subtropical subsidence zones. However, UTH calculated from climate simulations with 25 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) shows these tendencies only for parts of the winter-hemispheric dry belts. In the summer hemisphere, even though differences exist between the simulations, UTH is increasing in most dry zones, particularly in the South and North Pacific Ocean. None of the summer dry zones is expanding in these simulations. Upper-tropospheric dry zones estimated from observational data do not show any robust signs of change since 1979. Apart from a weak drying tendency at the poleward edge of the southern winter-hemispheric dry belt in infrared measurements, nothing indicates that the subtropical dry belts have expanded poleward. © 2020 American Meteorological Society.
英文关键词	Atmospheric humidity; Atmospheric pressure; Budget control; Climate change; Infrared drying; Subsidence; Tropics; Troposphere; Coupled Model Intercomparison Project; Infrared measurements; North Pacific Ocean; Observational data; Outgoing longwave radiation; Satellite-based sensors; Subtropical anticyclone; Tropospheric humidity; Climate models
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/171409
作者单位	Meteorological Institute, Center for Earth System Research and Sustainability (CEN), Department of Earth Sciences, Universitat € Hamburg, Hamburg, Germany; User Service and Climate Division, EUMETSAT, Darmstadt, Germany; GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
推荐引用方式 GB/T 7714	Tivig M.,Grützun V.,John V.O.,et al. Trends in upper-tropospheric humidity: Expansion of the subtropical dry zones?[J],2020,33(6).
APA	Tivig M.,Grützun V.,John V.O.,&Buehler S.A..(2020).Trends in upper-tropospheric humidity: Expansion of the subtropical dry zones?.Journal of Climate,33(6).
MLA	Tivig M.,et al."Trends in upper-tropospheric humidity: Expansion of the subtropical dry zones?".Journal of Climate 33.6(2020).