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Author(s): Ferraro AJ, Highwood EJ, Charlton-Perez AJ
Published: December, 2011
Publisher: Geophysical Research Letters
DOI: 10.1029/2011GL049761
Tags: Stratospheric Aerosols, Climate Modelling
URL: http://www.agu.org/pubs/crossref/2011/2011GL049761.shtml
Abstract: A fixed dynamical heating model is used to investigate the pattern of zonal-mean stratospheric temperature change resulting from geoengineering with aerosols composed of sulfate, titania, limestone and soot. Aerosol always heats the tropical lower stratosphere, but at the poles the response can be either heating, cooling, or neutral. The sign of the change in stratospheric Pole-Equator temperature difference depends on aerosol type, size and season. This has implications for modeling geoengineering impacts and the response of the stratospheric circulation.
Author(s): Harris BM, Highwood EJ
Published: March, 2011
Publisher: Journal of Geophysical Research
DOI: 201110.1029/2010JD014581
Tags: Volcanism, Climate Modelling
URL: http://www.agu.org/pubs/crossref/2011/2010JD014581.shtml
Abstract: In this study we quantify the relationship between the aerosol optical depth increase from a volcanic eruption and the severity of the subsequent surface temperature decrease. This investigation is made by simulating 10 different sizes of eruption in a global circulation model (GCM) by changing stratospheric sulfate aerosol optical depth at each time step. The sizes of the simulated eruptions range from Pinatubo-sized up to the magnitude of supervolcanic eruptions around 100 times the size of Pinatubo. From these simulations we find that there is a smooth monotonic relationship between the global mean maximum aerosol optical depth anomaly and the global mean temperature anomaly and we derive a simple mathematical expression which fits this relationship well. We also construct similar relationships between global mean aerosol optical depth and the temperature anomaly at every individual model grid box to produce global maps of best-fit coefficients and fit residuals. These maps are used with caution to find the eruption size at which a local temperature anomaly is clearly distinct from the local natural variability and to approximate the temperature anomalies which the model may simulate following a Tambora-sized eruption. To our knowledge, this is the first study which quantifies the relationship between aerosol optical depth and resulting temperature anomalies in a simple way, using the wealth of data that is available from GCM simulations.
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