Dear Steve,
What is obvious to you is not to any climatologists. Please refrain
from such speculation if you can't back it up with the physics of the
climate system. The mechanism for temperature change you describe is
wrong. And you could not keep stratospheric sulfur injected into the
tropics from reaching the Arctic, but since that is not how it works,
this is not a reason to be concerned with stratospheric geoengineering.
There are many other reasons to be concerned, but this is not one.
Alan
Alan Robock, Professor II (Distinguished Professor)
Editor, Reviews of Geophysics
Director, Meteorology Undergraduate Program
Associate Director, Center for Environmental Prediction
Department of Environmental Sciences Phone: +1-848-932-5751
Rutgers University Fax: +1-732-932-8644
14 College Farm Road E-mail: rob...@envsci.rutgers.edu
New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock
On 9/11/2012 5:03 AM, Stephen Salter wrote:
Hi All
Six out of the eight models in the Driscoll et al paper show near
surface-warming in Arctic winters following volcanic eruptions. This
is in line with figure 2a the Jones Hayward Boucher Robock 2010 paper
in Atmospheric Chemistry and Physics. The obvious mechanisms are
blanketing of outgoing radiation and side-scatter of high solar rays
that might have missed the polar regions. Given the concerns about
the loss of Arctic ice and increased methane release we will have to
be very careful not to let any geo-engineering sulphur that we inject
at low latitudes reach the Arctic in winter.
Stephen
On 10/09/2012 16:52, Simon Driscoll wrote:
Dear all,
the published version (no longer PiP) is now available here:
http://www.agu.org/pubs/crossref/2012/2012JD017607.shtml
Warm regards,
Simon
________________________________________________
Simon Driscoll
Atmospheric, Oceanic and Planetary Physics
Department of Physics
University of Oxford
Office: 01865 272930
Mobile: 07935314940
http://www2.physics.ox.ac.uk/contacts/people/driscoll
http://www.geoengineering.ox.ac.uk/people/who-are-we/simon-driscoll/
------------------------------------------------------------------------
*From:* geoengineering@googlegroups.com
[geoengineering@googlegroups.com] on behalf of Andrew Lockley
[andrew.lock...@gmail.com]
*Sent:* 14 August 2012 02:06
*To:* geoengineering
*Subject:* [geo] Coupled Model Intercomparison Project 5 (CMIP5)
simulations of climate following volcanic eruptions
http://www.agu.org/pubs/crossref/pip/2012JD017607.shtml
The ability of the climate models submitted to the Coupled Model
Intercomparison Project 5 (CMIP5) database to simulate the Northern
Hemisphere winter climate following a large tropical volcanic
eruption is assessed. When sulfate aerosols are produced by volcanic
injections into the tropical stratosphere and spread by the
stratospheric circulation, it not only causes globally averaged
tropospheric cooling but also a localized heating in the lower
stratosphere, which can cause major dynamical feedbacks. Observations
show a lower stratospheric and surface response during the following
one or two Northern Hemisphere (NH) winters, that resembles the
positive phase of the North Atlantic Oscillation (NAO). Simulations
from 13 CMIP5 models that represent tropical eruptions in the 19th
and 20th century are examined, focusing on the large-scale regional
impacts associated with the large-scale circulation during the NH
winter season. The models generally fail to capture the NH dynamical
response following eruptions. They do not sufficiently simulate the
observed post-volcanic strengthened NH polar vortex, positive NAO, or
NH Eurasian warming pattern, and they tend to overestimate the
cooling in the tropical troposphere. The findings are confirmed by a
superposed epoch analysis of the NAO index for each model. The study
confirms previous similar evaluations and raises concern for the
ability of current climate models to simulate the response of a major
mode of global circulation variability to external forcings. This is
also of concern for the accuracy of geoengineering modeling studies
that assess the atmospheric response to stratosphere-injected
particles.Received 13 February 2012; accepted 24 July 2012.
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