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Radiative forcing by tropospheric ozone: Impact of cloud representation
Author(s) -
Roelofs GeertJan
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900029
Subject(s) - longwave , shortwave , cloud forcing , forcing (mathematics) , radiative forcing , environmental science , atmospheric sciences , sky , tropospheric ozone , troposphere , climatology , radiative transfer , cloud cover , meteorology , cloud computing , physics , geology , aerosol , quantum mechanics , computer science , operating system
We investigate the effect of clouds on the radiative forcing by tropospheric ozone increases between the pre‐industrial and the present time, using the general circulation model ECHAM4. The results indicate that clouds attenuate the longwave forcing for clear sky conditions by about 20%, whereas it approximately doubles the shortwave forcing. The estimated total clear‐sky and cloudy‐sky forcings are 0.41 and 0.37 W m −2 , respectively. Analysis of reported forcing estimates shows that the magnitude of the longwave cloud effect is 20–30% of the clear‐sky longwave forcing. On the other hand, the shortwave cloud effect appears to depend largely on characteristics of the applied cloud distribution and the way clouds are treated in radiative transfer models, and varies between 30–250% of the clear‐sky shortwave forcing. Hence, present estimates of the cloud effect range from zero to as high as 0.1 W m −2 .