On 31/10/2013 20:01, Simone Tilmes wrote:
The following paper is now online available (JGR atmosphere):
http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50868/abstract
Enjoy! Simone
Tilmes, S., et al. (2013), The hydrological impact of geoengineering
in the Geoengineering Model Intercomparison Project (GeoMIP), J.
Geophys. Res. Atmos., 118, 11,036–11,058, doi:10.1002/jgrd.50868.
Abstract:
The hydrological impact of enhancing Earth’s albedo by solar radiation
management is investigated using simulations from 12 Earth System
models contributing to the Geoengineering Model Intercomparison
Project (GeoMIP). We contrast an idealized experiment, G1, where the
global mean radiative forcing is kept at preindustrial conditions by
reducing insolation while the CO2 concentration is quadrupled to a
4xCO2 experiment. The reduction of evapotranspiration over land with
instantaneously increasing CO2 concentrations in both experiments
largely contributes to an initial reduction in evaporation. A warming
surface associated with the transient adjustment in 4xCO2 generates an
increase of global precipitation by around 6.9% with large zonal and
regional changes in both directions, including a precipitation
increase of 10% over Asia and a reduction of 7% for the North American
summer monsoon. Reduced global evaporation persists in G1 with
temperatures close to preindustrial conditions. Global precipitation
is reduced by around 4.5%, and significant reductions occur over
monsoonal land regions: East Asia (6%), South Africa (5%), North
America (7%), and South America (6%). The general precipitation
performance in models is discussed in comparison to observations. In
contrast to the 4xCO2 experiment, where the frequency of months with
heavy precipitation intensity is increased by over 50% in comparison
to the control, a reduction of up to 20% is simulated in G1. These
changes in precipitation in both total amount and frequency of
extremes point to a considerable weakening of the hydrological cycle
in a geoengineered world.
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Emeritus Professor of Engineering Design School of Engineering
University of Edinburgh Mayfield Road Edinburgh EH9 3JL Scotland
[email protected] Tel +44 (0)131 650 5704 Cell 07795 203 195
WWW.see.ed.ac.uk/~shs
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
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