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DOI	10.1016/j.atmosres.2020.105418
	Atmospheric water vapor radiative effects on shortwave radiation under clear skies: A global spatiotemporal analysis
	Salamalikis V.; Vamvakas I.; Gueymard C.A.; Kazantzidis A.
发表日期	2021
ISSN	0169-8095
卷号	251
英文摘要	This global study analyzes how the total column water vapor (in terms of precipitable water, PW) is related to the attenuation of shortwave solar radiation (SWR) using data from the MERRA-2 reanalysis during 2000–2014 and SWR simulations obtained with the REST2 clear-sky radiation model. The water vapor radiative effect (WVRE) on SWR attenuation is investigated by comparing the clear-sky SWR predictions under humid and ideally dry atmospheres, whereas the quantitative effect of PW on WVRE is determined using the concept of precipitable water efficiency (PWE). At global scale, WVRE exhibits a distinct seasonal pattern ranging from –80.2 to 0 W m-2, with lower values in humid regions where PW is typically high (>4 cm), making the water vapor contribution relatively small. This is attributed to the saturation effect in water vapor absorption. Over arid regions, the solar irradiance attenuation is mainly controlled by the high aerosol loads, and less negative WVRE values are found. Over high-altitude regions, the low PW reduces the atmospheric absorption, resulting in low absolute WVRE magnitudes. PWE is found to extend globally between –133.7 and 0 W m-2 cm-1 on a monthly scale. This range is smaller on a long-term mean monthly or annual basis. On a long-term basis, the monthly PWE results are mainly concentrated between −20 and 0 W m−2 cm−1, generating leptokurtic and left-skewed distributions peaking between −10 and −8 W m−2 cm−1, depending on month. PWE is inversely related to PW on a long-term annual scale, indicating that PWE tends to zero under very humid conditions. A general nonlinear model is proposed to evaluate the hourly PWE at global scale on a monthly basis, separately for the two hemispheres. A PW trend analysis reveals that the Middle East, equatorial regions, central Europe, and Australia exhibit significant temporal trends, further inducing significant trends in WVRE. For those areas, WVRE trends are calculated between −3.3 and 1.5 W m−2 over the entire 15-year period. In addition, the global WVRE over landmasses is classified in terms of the Köppen-Geiger (KG) climate classification system. The most pronounced radiative effects are found over the equatorial regions, with an average WVRE of −63 W m−2. The Arid KG class provides a complex WVRE pattern ranging from −66 to −24 W m−2. Further segregation of this class shows strongly variable WVRE, induced by local climate differentiation. Over Warm Temperate climates, WVRE is found to vary widely according to the various KG subclasses. For the Cold climate class, PW is mainly concentrated around 1 cm and WVRE is low. The Polar regions include high mountains where WVRE is low, with a median close to −28 W m−2. © 2020 Elsevier B.V.
英文关键词	Atmospheric water vapor; Global shortwave irradiance; Köppen-Geiger climate classification; Water vapor efficiency; Water vapor radiative effects
语种	英语
scopus关键词	Atmospheric radiation; Radiation effects; Solar radiation; Water absorption; Atmospheric absorption; Atmospheric water vapor; Classification system; Quantitative effects; Short-wave radiation; Skewed distribution; Spatiotemporal analysis; Water-vapor absorption; Water vapor; climate classification; radiative forcing; shortwave radiation; spatiotemporal analysis; trend analysis; water vapor
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/162209
作者单位	Laboratory of Atmospheric Physics, Department of Physics, University of Patras, Patras, GR 26500, Greece; Solar Consulting Services, Colebrook, NH 03576, United States
推荐引用方式 GB/T 7714	Salamalikis V.,Vamvakas I.,Gueymard C.A.,et al. Atmospheric water vapor radiative effects on shortwave radiation under clear skies: A global spatiotemporal analysis[J],2021,251.
APA	Salamalikis V.,Vamvakas I.,Gueymard C.A.,&Kazantzidis A..(2021).Atmospheric water vapor radiative effects on shortwave radiation under clear skies: A global spatiotemporal analysis.Atmospheric Research,251.
MLA	Salamalikis V.,et al."Atmospheric water vapor radiative effects on shortwave radiation under clear skies: A global spatiotemporal analysis".Atmospheric Research 251(2021).