Hi Stephen‹I would think that Chinese sulfate (like tropospheric sulfate from virtually anywhere) would contribute to cloud and free air brightening, so a cooling influence (especially when that sulfate is above the dark Pacific Ocean). Now, in that coal plants put out more than pure SO2, there might well be some components (such as black carbon) that would exert a strong warming influence, especially if they are carried far enough to deposit on snow and/or ice during the sunny half of the year in the Arctic. For net effect, there is need for much more analysis than I have seen.
On limiting heat reaching the Arctic Ocean, there have been suggestions to even build a dam across the Bering Strait‹as long ago as the mid-20th century (though I think then it was with the intent to warm the Arctic). My guess on the kelp idea is that the sunny part of the year is not long enough for that approach to be all that practical (not only is the sunny part of the year short, but the sun angle is often not helpful). And sea ice is typically only a few meters thickness, so no where near 30 m. Mike On 9/11/12 12:48 PM, "Stephen Salter" <[email protected]> wrote: > > Mike > > Do you think that the higher levels of SO2 from Chinese coal burning could > account for some of the increase in Arctic temperatures? > > Another thought for your list might be to increase the drag of water flowing > in through the Bering Strait. In summer kelp grows at an amazing rate but not > below about 30 metre water depth because of the shortage of light. The net > flow is 800,000 m3 a second and it will be warmer than polar water so a small > velocity reduction makes a big difference. What if we put strong ropes moored > at 30 metres to give them kelp a foot hold? If kelp gets scraped off by > floating ice it will can grow again. Does ice reach down to 30 metres? > > Stephen > > On 11/09/2012 18:05, Mike MacCracken wrote: > > >> Re: [geo] Coupled Model Intercomparison Project 5 (CMIP5) simulations of >> climate following volcanic eruptions In my view, this is just why >> geoengineering efforts to cool the Arctic should consider as approaches: (a) >> spring-summer only injection of the appropriate sulfur compound (whatever >> will lead to sulfates) into the LOWER stratosphere or free troposphere, (b) >> cloud brightening in region or over currents carrying heat into the region, >> (c) approaches to brighten the surface albedo (e.g., microbubbles) in or near >> the region, and, perhaps, (d) approaches to reduce cirrus that are reducing >> IR loss. >> >> Parallel to these efforts, we should also be working to limit emissions of >> substances that amplify Arctic warming above and beyond the amplification >> that happens due to natural processes, so black carbon from sources in and >> near the region, etc. >> >> Mike >> >> >> >> >> On 9/11/12 5:03 AM, "Stephen Salter" <[email protected]> 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: [email protected] [[email protected]] on >>>> behalf of Andrew Lockley [[email protected]] >>>> 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. >>>> -- >>>> You received this message because you are subscribed to the Google Groups >>>> "geoengineering" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]. >>>> For more options, visit this group at >>>> http://groups.google.com/group/geoengineering?hl=en. >>>> >>>> >>>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google Groups >>>> "geoengineering" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]. >>>> For more options, visit this group at >>>> http://groups.google.com/group/geoengineering?hl=en. >>>> >>>> >>> >>> >>> >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "geoengineering" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/geoengineering?hl=en. >> > > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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