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The present‐day decadal solar cycle modulation of Earth's radiative forcing via charged H 2 SO 4 /H 2 O aerosol nucleation
Author(s) -
Kazil J.,
Zhang K.,
Stier P.,
Feichter J.,
Lohmann U.,
O'Brien K.
Publication year - 2012
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 - 10.1029/2011gl050058
Subject(s) - aerosol , radiative forcing , atmospheric sciences , radiative transfer , atmosphere (unit) , solar irradiance , environmental science , cloud albedo , cloud forcing , solar cycle , physics , cloud cover , meteorology , solar wind , plasma , cloud computing , quantum mechanics , computer science , operating system
The decadal solar cycle modulation of Earth's radiative forcing via ionization of the atmosphere by galactic cosmic rays, aerosol formation from the gas phase, and the response of clouds to aerosol is quantified for the first time with a climate model that represents and couples the relevant processes. Simulations are conducted for solar maximum and minimum conditions, with present‐day anthropogenic aerosol and aerosol precursor gas emissions, and contemporary large‐scale meteorology. The solar cycle signal appears in atmospheric ionization, aerosol formation from the gas phase, aerosol concentrations, aerosol optical depth, and in cloud properties, and is most pronounced at mid‐ and high latitudes. The resulting solar cycle modulation of Earth's radiative forcing exhibits a distinct hemispheric asymmetry, with peak values of −0.14 W m −2 in the southern and −0.06 W m −2 in the northern mid‐latitudes. Globally and annually averaged, the solar cycle modulation of Earth's radiative forcing, arising from the increase in atmospheric ionization by galactic cosmic rays from solar maximum to minimum, via charged nucleation of aerosol, the direct aerosol effect, and the cloud albedo effect, amounts to −0.05 W m −2 . A limited relevance of this variation for the Earth's atmosphere and climate can be inferred, given that Earth's radiative forcing changes by −0.24 W m −2 from solar maximum to minimum because of a decrease in total solar irradiance.