Journal article
Daytime variation of aerosol optical depth in North China and its impact on aerosol direct radiative effects
Atmospheric environment (1994), Vol.182, pp.31-40
06/2018
DOI: 10.1016/j.atmosenv.2018.03.024
Abstract
Daytime cycles of aerosol optical depth (AOD) and Angstrom exponent (AE) climatology were analyzed based on long-term (5–15 years) measurements at 18 stations of the China Aerosol Remote Sensing Network (CARSNET) in North China. AOD in Northwest China (NWC) exhibits a daytime trend with negative departures in the early morning and later afternoon while positive departures at midday. Daytime AOD relative departure in different sites and seasons varies from −30.26% to 30.28%. AE in NWC shows an opposite pattern to daytime variation of AOD. Daytime variation of AE is negligible in North China Plain (NCP), AOD increases steadily throughout the day. This trend is consistent and repeatable in four seasons. Such pronounced variability in AOD and AE should be taken accounted for in the estimation of diurnal aerosol direct radiative effects (ADRE), as suggested by the radiative transfer model simulations. The replacement of the observed daytime variation of AOD and AE by daytime mean values in NWC results in ADRE differences of 0.31 Wm−2 at the surface and 0.05 Wm−2 at the top of the atmosphere (TOA). ADRE in NWC will be underestimated by −0.47 Wm-2 and -0.25 Wm-2 at the surface and TOA, respectively, if instantaneous AOD and AE during the overpass time of Terra and Aqua are taken as the daytime mean values. The annual mean ADRE at the surface and TOA will be underestimated by −0.17 Wm-2 and -0.03 Wm-2 if daytime variations of AOD and AE are replaced by daytime mean values in NCP. ADRE will be underestimated by −0.07 Wm-2 at the surface and −0.06 Wm-2 at the TOA if instantaneous AOD and AE during the overpass time of Terra and Aqua other than daytime variation of AOD and AE are used in the calculations.
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•Daytime variations of AOD and AE in Northwest China and North China Plain.•Daytime variation of AOD on ADRE at the surface and TOA should be accounted for.•Caution should be taken in using MODIS AOD to represent daytime mean value.
Details
- Title: Subtitle
- Daytime variation of aerosol optical depth in North China and its impact on aerosol direct radiative effects
- Creators
- Jingjing Song - LAGEO, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, ChinaXiangao Xia - LAGEO, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, ChinaHuizheng Che - State Key Laboratory of Severe Weather (LASW) and Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences (CAMS), CMA, Beijing, 10081, ChinaJun Wang - Department of Chemical and Biochemical Engineering, Center for Global and Regional Environmental Studies, and Informatics Initiative, University of Iowa, Iowa City, IA 52241, USAXiaoling Zhang - School of Atmospheric Sciences, Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, Chengdu University of Information Technology, Chengdu, 610225, ChinaXiaojing Li - National Satellite Meteorological Center, China Meteorological Administration, Beijing, 100082, China
- Resource Type
- Journal article
- Publication Details
- Atmospheric environment (1994), Vol.182, pp.31-40
- DOI
- 10.1016/j.atmosenv.2018.03.024
- ISSN
- 1352-2310
- eISSN
- 1873-2844
- Publisher
- Elsevier Ltd
- Grant note
- name: National key research and development program of China, award: 2016YFC0200403, 2017YFA0603504; DOI: 10.13039/501100001809, name: National Science Foundation of China, award: 41475138, 41675033, 41475026, 91644217, 41590874; DOI: 10.13039/501100005150, name: CAMS Basis Research Project, award: 2017Z11, 2016Z001, 2014R17; name: Climate Change Special Fund of CMA, award: CCSF201504
- Language
- English
- Date published
- 06/2018
- Academic Unit
- Electrical and Computer Engineering; Civil and Environmental Engineering; Iowa Technology Institute; Physics and Astronomy; Chemical and Biochemical Engineering
- Record Identifier
- 9984104807102771
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