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Effects of stratospheric sulfate aerosol geo‐engineering on cirrus clouds
Author(s) -
Kuebbeler Miriam,
Lohmann Ulrike,
Feichter Johann
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 - 10.1029/2012gl053797
Subject(s) - cirrus , stratosphere , atmospheric sciences , troposphere , aerosol , environmental science , parametrization (atmospheric modeling) , forcing (mathematics) , radiative forcing , ice nucleus , climatology , sulfate aerosol , ice crystals , nucleation , meteorology , geology , physics , radiative transfer , optics , thermodynamics
Cooling the Earth through the injection of sulphate into the stratosphere is one of the most discussed geo‐engineering (GE) schemes. Stratospheric aerosols can sediment into the troposphere, modify the aerosol composition and thus might impact cirrus clouds. We use a global climate model with a physically based parametrization for cirrus clouds in order to investigate possible microphysical and dynamical effects. We find that enhanced stratospheric aerosol loadings as proposed by several GE approaches will likely lead to a reduced ice crystal nucleation rate and thus optically thinner cirrus clouds. These optically thinner cirrus clouds exert a strong negative cloud forcing in the long‐wave which contributes by 60% to the overall net GE forcing. This shows that indirect effects of stratospheric aerosols on cirrus clouds may be important and need to be considered in order to estimate the maximum cooling derived from stratospheric GE.