Visioni, Daniele; et al. (2017): Sulfate geoengineering impact on methane transport and lifetime. Results from the Geoengineering Model Intercomparison Project (GeoMIP)

Visioni, Daniele; Pitari, Giovanni; Aquila, Valentina; Tilmes, Simone; Cionni, Irene; Di Genova, Glauco; Mancini, Eva (2017): Sulfate geoengineering impact on methane transport and lifetime. Results from the Geoengineering Model Intercomparison Project (GeoMIP). In Atmos. Chem. Phys 17 (18), pp.[nbsp]11209–11226. DOI: 10.5194/acp-17-11209-2017.

Sulfate geoengineering (SG), made by sustained injection of SO2 in the tropical lower stratosphere, may impact the CH4 abundance through several photochemical mechanisms affecting tropospheric OH and hence the methane lifetime. (a)[nbsp]The reflection of incoming solar radiation increases the planetary albedo and cools the surface, with a tropospheric H2O decrease. (b)[nbsp]The tropospheric UV budget is upset by the additional aerosol scattering and stratospheric ozone changes: the net effect is meridionally not uniform, with a net decrease in the tropics, thus producing less tropospheric O(1D). (c)[nbsp]The extratropical downwelling motion from the lower stratosphere tends to increase the sulfate aerosol surface area density available for heterogeneous chemical reactions in the mid-to-upper troposphere, thus reducing the amount of NOx and O3 production. (d)[nbsp]The tropical lower stratosphere is warmed by solar and planetary radiation absorption by the aerosols.

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