[geo] AMS Joint Session: Aerosol Approaches to Climate Engineering, Boston, Jan. 16-20, 2020

[Alan Robock]

Robert Dickinson Symposium

https://ams.confex.com/ams/2020Annual/webprogrampreliminary/DICKINSONSYMP.html

Joint Session Aerosol Approaches to Climate Engineering (e.g., results from 
climate modeling, using analogs such as volcanic eruptions and ship tracks, and 
development of technology to actually implement solar geoengineering)
Keynote:
Simone 
Tilmes,
 NCAR, Boulder, CO

Description:

This joint session covers broad topics such as results from climate modeling, 
using analogs such as volcanic eruptions and ship tracks, and development of 
technology to actually implement solar geoengineering. Papers on the physics of 
climate engineering should be submitted to this joint session, and on ethical 
and governance issues related to climate engineering to the session "Ethics and 
governance of weather modification and geoengineering" at the 22nd Conference 
on Planned and Inadvertent Weather Modification.

To submit abstracts:
https://ams.confex.com/ams/2020Annual/webprogrampreliminary/Session51511.html

--
Alan
_
Alan Robock, Distinguished Professor
  Associate Editor, Reviews of Geophysics
Department of Environmental Sciences Phone: +1-848-932-5751
Rutgers UniversityE-mail: 
rob...@envsci.rutgers.edu
14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
New Brunswick, NJ 08901-8551  USA  ☮  http://twitter.com/AlanRobock

-- 
You received this message because you are subscribed to the Google Groups 
"geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to geoengineering+unsubscr...@googlegroups.com.
To post to this group, send email to geoengineering@googlegroups.com.
Visit this group at https://groups.google.com/group/geoengineering.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/geoengineering/849090ee-86f2-dd93-1341-cf40ce39fa45%40envsci.rutgers.edu.
For more options, visit https://groups.google.com/d/optout.

Re: [geo] Sensitivity of the surface climate to the height of the stratospheric sulfate layer

[Andrew Lockley]

This is very important for engineering, as it favours high-altitude
technologies (rockets, guns) vs air-breathing aircraft.

What is the optimal injection altitude, in your opinion? At some point, the
aerosol or precursor would be at risk of mixing into the mesosphere.

Andrew

On Fri, 24 May 2019, 07:09 Govindasamy Bala,  wrote:

> Dear All,
>
> This work is now published in Earth System Dynamics as a discussion paper.
> When we started this work, we had hard time understanding the sensitivity
> to the height of the sulfate aerosol layer. In the paper, we explain the
> sensitivity in terms of the effective radiative forcing.
>
>
> https://www.earth-syst-dynam-discuss.net/esd-2019-21/
> ESDD - Climate System Response to Stratospheric Sulfate Aerosols:
> Sensitivity to Altitude of Aerosol Layer - earth-syst-dynam-discuss.net
> 
> www.earth-syst-dynam-discuss.net
> We find that sulfate aerosols are more effective in cooling the climate
> system when they reside higher in the stratosphere. We explain this
> sensitivity in terms of radiative forcing at the top of the atmosphere.
>
> *Abstract*
> Reduction of surface temperatures of the planet by injecting sulfate
> aerosols in the stratosphere has been suggested
> as an option to reduce the amount of human-induced climate warming.
> Several previous studies have shown that for a specified amount of
> injection, aerosols injected at a higher altitude in the stratosphere would
> produce more cooling because aerosol sedimentation would take longer time.
> In this study, we isolate and assess the sensitivity to the altitude of the
> aerosol layer of stratospheric aerosol radiative forcing and the resulting
> climate change. We study this by prescribing a specified amount of sulfate
> aerosols, of a size typical of what is produced by volcanoes, distributed
> uniformly at different levels in the stratosphere. We find that
> stratospheric sulfate aerosols are more effective in cooling climate when
> they reside higher in the stratosphere. We explain this sensitivity in
> terms of effective radiative forcing: volcanic aerosols heat the
> stratospheric layers where they reside, altering stratospheric water vapor
> content, tropospheric stability and clouds, and consequently the effective
> radiative forcing. We show that the magnitude of the effective radiative
> forcing is larger when aerosols are prescribed at higher altitudes and the
> differences in radiative forcing due to fast adjustment processes can
> account for a substantial part of the dependence of amount of cooling on
> aerosol altitude. These altitude effects would be additional to dependences
> on aerosol microphysics, transport, and sedimentation, which are outside
> the scope of this study. The cooling effectiveness of stratospheric sulfate
> aerosols likely increases with altitude of the aerosol layer both because
> aerosols higher in the stratosphere have larger effective radiative forcing
> and because they have a longer stratospheric residence time; these two
> effects are likely to be of comparable importance.
> --
> With Best Wishes,
>
> ---
> G. Bala
> Professor
> Center for Atmospheric and Oceanic Sciences
> Indian Institute of Science
> Bangalore - 560 012
> India
>
> Tel: +91 80 2293 3428; +91 80 2293 2505
> Fax: +91 80 2360 0865; +91 80 2293 3425
> Email: gb...@iisc.ac.in; bala@gmail.com
> Web:  http://dccc.iisc.ac.in/bg.html
> ---
>
> --
> You received this message because you are subscribed to the Google Groups
> "geoengineering" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to geoengineering+unsubscr...@googlegroups.com.
> To post to this group, send email to geoengineering@googlegroups.com.
> Visit this group at https://groups.google.com/group/geoengineering.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/geoengineering/CAD7fhV%3D9Qko-S681Y3vS7qdgK3n7LFZ0_6FCJdDkE9VffPR6RQ%40mail.gmail.com
> 
> .
> For more options, visit https://groups.google.com/d/optout.
>

-- 
You received this message because you are subscribed to the Google Groups 
"geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to geoengineering+unsubscr...@googlegroups.com.
To post to this group, send email to geoengineering@googlegroups.com.
Visit this group at https://groups.google.com/group/geoengineering.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/geoengineering/CAJ3C-067C-sq55NaVUemEa9Wf9%2B7tpRY08%3DQKjjrm9%2B_Yqb8DQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.

[geo] Sensitivity of the surface climate to the height of the stratospheric sulfate layer

[Govindasamy Bala]

Dear All,

This work is now published in Earth System Dynamics as a discussion paper.
When we started this work, we had hard time understanding the sensitivity
to the height of the sulfate aerosol layer. In the paper, we explain the
sensitivity in terms of the effective radiative forcing.


https://www.earth-syst-dynam-discuss.net/esd-2019-21/
ESDD - Climate System Response to Stratospheric Sulfate Aerosols:
Sensitivity to Altitude of Aerosol Layer - earth-syst-dynam-discuss.net

www.earth-syst-dynam-discuss.net
We find that sulfate aerosols are more effective in cooling the climate
system when they reside higher in the stratosphere. We explain this
sensitivity in terms of radiative forcing at the top of the atmosphere.

*Abstract*
Reduction of surface temperatures of the planet by injecting sulfate
aerosols in the stratosphere has been suggested
as an option to reduce the amount of human-induced climate warming. Several
previous studies have shown that for a specified amount of injection,
aerosols injected at a higher altitude in the stratosphere would produce
more cooling because aerosol sedimentation would take longer time. In this
study, we isolate and assess the sensitivity to the altitude of the aerosol
layer of stratospheric aerosol radiative forcing and the resulting climate
change. We study this by prescribing a specified amount of sulfate
aerosols, of a size typical of what is produced by volcanoes, distributed
uniformly at different levels in the stratosphere. We find that
stratospheric sulfate aerosols are more effective in cooling climate when
they reside higher in the stratosphere. We explain this sensitivity in
terms of effective radiative forcing: volcanic aerosols heat the
stratospheric layers where they reside, altering stratospheric water vapor
content, tropospheric stability and clouds, and consequently the effective
radiative forcing. We show that the magnitude of the effective radiative
forcing is larger when aerosols are prescribed at higher altitudes and the
differences in radiative forcing due to fast adjustment processes can
account for a substantial part of the dependence of amount of cooling on
aerosol altitude. These altitude effects would be additional to dependences
on aerosol microphysics, transport, and sedimentation, which are outside
the scope of this study. The cooling effectiveness of stratospheric sulfate
aerosols likely increases with altitude of the aerosol layer both because
aerosols higher in the stratosphere have larger effective radiative forcing
and because they have a longer stratospheric residence time; these two
effects are likely to be of comparable importance.
-- 
With Best Wishes,

---
G. Bala
Professor
Center for Atmospheric and Oceanic Sciences
Indian Institute of Science
Bangalore - 560 012
India

Tel: +91 80 2293 3428; +91 80 2293 2505
Fax: +91 80 2360 0865; +91 80 2293 3425
Email: gb...@iisc.ac.in; bala@gmail.com
Web:  http://dccc.iisc.ac.in/bg.html
---

-- 
You received this message because you are subscribed to the Google Groups 
"geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to geoengineering+unsubscr...@googlegroups.com.
To post to this group, send email to geoengineering@googlegroups.com.
Visit this group at https://groups.google.com/group/geoengineering.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/geoengineering/CAD7fhV%3D9Qko-S681Y3vS7qdgK3n7LFZ0_6FCJdDkE9VffPR6RQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.