Calendar Event Details
AEROCENTER: Valentina Aquila
Affiliation: GESTAR/Johns Hopkins/Code 614
Event Date: Tuesday, April 1, 2014
Location: G133
Time: 11:00 AM
The stratospheric effects of solar radiation management geoengineering
Geoengineering is defined as the deliberate human intervention on the Earth-atmosphere system in order to mitigate global warming. Using the NASA Goddard Earth Observing System Chemistry Climate Model (GEOSCCM), we investigated the climate effects of the artificial injection of sulfate aerosol in the stratosphere in order to reduce the solar radiation reaching the surface. We performed an ensemble of three 2010-2090 simulations, and the relative control simulations, as part of the Geoengineering Model Intercomparison Project. In these simulations, performed with the IPCC scenario RCP4.5, we injected 20 Tg/year of sulfur dioxide at the equator between 16 km and 25 km altitude from 2020 to 2070. The sulfur dioxide is transformed into sulfate by the GEOSCCM. The GEOSCCM includes radiatively interactive aerosols and a coupling between aerosols and stratospheric chemistry through the aerosol surface area density.
The GEOSCCM also includes an internally generated QBO. In our simulations, the geoengineered aerosol causes an ozone decrease with respect to the control simulations, especially in the southern high latitudes. The changes in ozone concentrations are a combination of the changes due to the aerosol perturbation to the chemistry and dynamics of the stratosphere. Additionally, the geoengineering aerosol leads to a warming of the tropical tropopause of about 2 to 4 K and a subsequent increase of stratospheric water vapour by about 0.5 ppmv. We also find that the geoengineering aerosol also significantly modulates the QBO, possibly leading to its complete disruption.
Posted or updated: Tuesday, March 25, 2014
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