DOI: 10.1002/joc.5544
论文题名: A new measure of the effect of cloud cover on annual/monthly mean global radiation for investigating the cause of secular trends in global radiation
作者: Kanno A. ; Ishida H. ; Tanaka Y.
刊名: International Journal of Climatology
ISSN: 8998418
出版年: 2018
卷: 38, 期: 10 起始页码: 3917
结束页码: 3926
语种: 英语
英文关键词: aerosol
; cause
; decadal trend
; global brightening
; global radiation
; long-term trend
; nonlinear regression
; radiative effect
Scopus关键词: Aerosols
; Regression analysis
; Solar radiation
; Cause
; Decadal trend
; Global brightening
; Global radiation
; Long-term trend
; Non-linear regression
; Radiative effects
; Atmospheric radiation
; aerosol
; annual variation
; cloud cover
; cloud radiative forcing
; decadal variation
; nonlinearity
; radiation balance
; trend analysis
英文摘要: The annual to monthly average of short-term (hourly/minutely) measured global radiation (GR), hereafter called mean global radiation (MGR), has shown large secular trends (decadal or longer term) globally that are only attributable to clouds or aerosols. In order to investigate whether changes in cloud cover (CC) contribute to the MGR trend for a given location and period of interest, many studies compare secular trends of MGR and mean cloud cover (MCC, the annual to monthly average of CC). If these trends have opposite signs, such studies assume that the changes in CC cause the changes in MGR, and vice versa. However, this approach is misleading because MCC is not an appropriate measure of the averaged immediate effect of CC on GR for the year or month due to the solar-elevation dependency and the inherent nonlinearity in the instantaneous effect. As a practical solution, we derived a more reasonable measure named MRRCC (mean radiation reduction by CC) to replace MCC. This is the annual to monthly average of the immediate reduction in GR arising from CC and is determined using a nonlinear regression model that relates immediate GR to the corresponding CC, solar elevation, and year. We carefully designed the model so that the calculation of MRRCC does not require any other variables (such as aerosol measurements). According to our tests at 42 observation stations with increasing MGR trends from 1990 to 2009, 24 stations had positive trends in MCC, indicating in the conventional approach that CC is not a cause of the MGR increase. However, 14 out of these 24 stations had negative MRRCC trends, indicating that CC is one cause of the MGR increase. This demonstrates that the use of MRRCC instead of MCC can alter our understanding of the causes of MGR trends globally. © 2018 Royal Meteorological Society Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/116822
Appears in Collections: 气候减缓与适应
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作者单位: Graduate School of Science and Technology for Innovation, Yamaguchi University, Ube, Japan; Climate Research Department, Meteorological Research Institute, Tsukuba, Japan; Disaster Prevention Department, ECOH Corporation, Ueno, Japan
Recommended Citation:
Kanno A.,Ishida H.,Tanaka Y.. A new measure of the effect of cloud cover on annual/monthly mean global radiation for investigating the cause of secular trends in global radiation[J]. International Journal of Climatology,2018-01-01,38(10)