DOI: 10.1073/pnas.1921231117
论文题名: Aerosols enhance cloud lifetime and brightness along the stratus-to-cumulus transition
作者: Christensen M.W. ; Jones W.K. ; Stier P.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2020
卷: 117, 期: 30 起始页码: 17591
结束页码: 17598
语种: 英语
英文关键词: Aerosols
; Clouds
; Radiative forcing
Scopus关键词: albedo
; Article
; atmosphere
; brightness
; climate change
; cloud
; cloud lifetime
; controlled study
; environmental temperature
; precipitation
; priority journal
; seasonal variation
; stratus to cumulus transition
; weather
英文摘要: Anthropogenic aerosols are hypothesized to enhance planetary albedo and offset some of the warming due to the buildup of greenhouse gases in Earth’s atmosphere. Aerosols can enhance the coverage, reflectance, and lifetime of warm low-level clouds. However, the relationship between cloud lifetime and aerosol concentration has been challenging to measure from polar orbiting satellites. We estimate two timescales relating to the formation and persistence of low-level clouds over 1◦ × 1◦ spatial domains using multiple years of geostationary satellite observations provided by the Clouds and Earth’s Radiant Energy System (CERES) Synoptic (SYN) product. Lagrangian trajectories spanning several days along the classic stratus-to-cumulus transition zone are stratified by aerosol optical depth and meteorology. Clouds forming in relatively polluted trajectories tend to have lighter precipitation rates, longer average lifetime, and higher cloud albedo and cloud fraction compared with unpolluted trajectories. While liquid water path differences are found to be negligible, we find direct evidence of increased planetary albedo primarily through increased drop concentration (Nd) and cloud fraction, with the caveat that the aerosol influence on cloud fraction is positive only for stable atmospheric conditions. While the increase in cloud fraction can be large typically in the beginning of trajectories, the Twomey effect accounts for the bulk (roughly 3/4) of the total aerosol indirect radiative forcing estimate. © 2020 National Academy of Sciences. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164113
Appears in Collections: 气候变化与战略
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作者单位: Christensen, M.W., Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom; Jones, W.K., Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom; Stier, P., Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom
Recommended Citation:
Christensen M.W.,Jones W.K.,Stier P.. Aerosols enhance cloud lifetime and brightness along the stratus-to-cumulus transition[J]. Proceedings of the National Academy of Sciences of the United States of America,2020-01-01,117(30)