Your explanation may be right and mine is probably wrong, but surface albedo change does affect downward shortwave because there are reflections off of cloud bottoms.
This effect is strongest in the arctic where there is both high cloudiness and high surface albedo, making multiple reflections important. On Sat, Mar 24, 2012 at 6:37 PM, Alan Robock <[email protected]>wrote: > Dear Ken, > > Actually, the GISS ModelE has a little too much sea ice. However, if you > look at Fig. 9 of our first geoengineering paper, > http://climate.envsci.rutgers.edu/pdf/2008JD010050small.pdf , you will > see that we indeed had an increase in sea ice in the very location that the > Hadley model shows an increase in absorbed solar. Our sea ice is not that > bad, but the entire Arctic is covered for the current climate, which is too > much sea ice. > > So the answer lies in clouds. What is plotted is changes in downward > solar, not net downward solar, so sea ice does not matter. How much was > your wager? > > By the way, the polar plots are great. How was that done? > > > Alan > > [On sabbatical for current academic year. The best way to contact me is > by email, [email protected], or at 732-881-1610 (cell).] > > 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: +1-732-932-9800 x6222 > Rutgers University Fax: +1-732-932-8644 > 14 College Farm Road E-mail: [email protected] > New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock > > > > > On Mar 24, 2012, at 1:44 AM, Ken Caldeira wrote: > > Note that the papre says: > > The cooling is generally > stronger over land than over ocean in both models, > but HadGEM2 also shows cooling over the Arctic which > is much stronger than that in ModelE. However, a problem > has since been identified with the sea-ice scheme in the > ModelE simulations of Robock et al. (2008) analysed here, > which resulted in sea-ice being less responsive to temperature > changes than it should be. > > > HadGEM2 is probably getting more downward surface shortwave because it has > more sea ice and thus a higher surface albedo. Some of the upward directed > shortwave hits clouds etc and is re-re-radiated downward. With less sea > ice Robock's ocean absorbs the downward shortwave, hence there is less > downward shortwave at the surface. > > This is just a speculation, but if I were analyzing these model results, > that is where I would start looking. > > > If I had to wager, I'd wager that the primary diffference in these figures > is due to the sea-ice bug in Robock's simulations. > > > On Sat, Mar 24, 2012 at 9:31 AM, Ken Caldeira < > [email protected]> wrote: > >> If under stand it these represent means of a single decade in single >> model simulations. >> >> Unless we know the decadal variability in these models from the control >> runs, it is difficult to assess the significant of these results. The >> Arctic is often one of the most variable regions in a climate model. >> >> I would be cautious of reading too much into regional results from single >> realizations for periods of single decades. (Isn't this exactly what >> climate science deniers tend to do?) >> >> >> >> On Sat, Mar 24, 2012 at 1:48 AM, Mick West <[email protected]> wrote: >> >>> I'd just mapped those two images onto Google Earth specifically for that >>> reason: >>> >>> [image: Inline image 2] >>> >>> [image: Inline image 3] >>> >>> Antarctic is also interesting: >>> >>> [image: Inline image 4] >>> >>> [image: Inline image 5] >>> >>> The HadGem2 model seems much more sensitive to land/sea mass >>> >>> Mick. >>> >>> >>> On Fri, Mar 23, 2012 at 5:37 PM, Alan Robock >>> <[email protected]>wrote: >>> >>>> It's a tiny area - looks larger on a lat-lon plot, and there is a lot >>>> of natural variability. I don't thing these details should be of concern. >>>> Also, notice in Fig. 1 that the stratospheric forcing is different. I >>>> cannot say which model is better. >>>> >>>> >>>> Alan >>>> >>>> [On sabbatical for current academic year. The best way to contact me >>>> is by email, [email protected], or at 732-881-1610 (cell).] >>>> >>>> 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: +1-732-932-9800 x6222 >>>> Rutgers University Fax: +1-732-932-8644 >>>> 14 College Farm Road E-mail: [email protected] >>>> New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock >>>> >>>> >>>> On 3/23/2012 5:05 PM, Oliver Wingenter wrote: >>>> >>>> Dear Alan, >>>> >>>> Quit a difference between the two models in ACP paper Fig. 2. Does the >>>> HadGEM2 treat the opital properties of the particles more realistically >>>> than ModelE, i.e. the extra light that will be scattered towards the poles >>>> and the lower effectiveness of sulfate aerosols near the poles because of >>>> the incident sun angle. >>>> >>>> Oliver Wingenter >>>> >>>> On 3/23/2012 11:07 AM, Stephen Salter wrote: >>>> >>>> Dear Alan >>>> >>>> That is exactly the paper I mean. Are you not alarmed at the possible >>>> effect of 10 watts per square metre of warming in the Arctic on the rate of >>>> methane release? >>>> >>>> Stephen >>>> >>>> >>>> On 23/03/2012 16:29, Alan Robock wrote: >>>> >>>> Dear Steve, >>>> >>>> I don't think the point is subtle at all. I am concerned about global >>>> warming and its impacts. *BUT THIS DOES NOT TRANSLATE INTO A NEED FOR >>>> GEOENGINEERING*. I hope that is not subtle. There are several other >>>> possible responses to global warming, including rapid mitigation, which we >>>> could do today with solar and wind, efficiency and conservation, and >>>> including adaptation. If the dangers of geoengineering outweigh the >>>> dangers of global warming, then we should not do it, and we just don't know >>>> yet. That's why we need more research. >>>> >>>> I have no idea what you mean about Fig. 2b of my my ACP paper. Are you >>>> asking about this paper? >>>> >>>> Jones, Andy, Jim Haywood, Olivier Boucher, Ben Kravitz, and Alan >>>> Robock, 2010: Geoengineering by stratospheric SO2 injection: Results >>>> from the Met Office HadGEM2 climate model and comparison with the Goddard >>>> Institute for Space Studies ModelE. *Atmos. Chem. Phys.*, *10*, >>>> 5999-6006, doi:10.5194/acp-10-5999-2010. >>>> http://www.atmos-chem-phys.net/10/5999/2010/acp-10-5999-2010.pdf >>>> >>>> It is my only ACP paper on geoengineering. Here is Fig. 2: >>>> >>>> >>>> <Mail Attachment.png> >>>> >>>> First of all it is the change in surface shortwave from two different >>>> models. It is not temperature change. What concerns me is how different >>>> the two models are, by a factor of two, and with different patterns, which >>>> tells me that we really don't understand this well at all yet. Is that >>>> what concerns you? This is why we are doing GeoMIP, to look at many more >>>> models doing the same experiments, so we can better understand the forcing >>>> and response. >>>> >>>> And what does figure 2b have to with methane release???? >>>> >>>> >>>> Alan >>>> >>>> [On sabbatical for current academic year. The best way to contact me >>>> is by email, [email protected], or at 732-881-1610 (cell).] >>>> >>>> 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: +1-732-932-9800 x6222 >>>> Rutgers University Fax: +1-732-932-8644 >>>> 14 College Farm Road E-mail: [email protected] >>>> New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock >>>> >>>> >>>> On 3/23/2012 9:09 AM, Stephen Salter wrote: >>>> >>>> Dear Alan >>>> >>>> The difference between my Commons statement and your position is too >>>> subtle for me. Do you mean that you are not alarmed about the possibility >>>> of the need for geoengineering becoming apparent? >>>> >>>> I could not possibly ask everybody because I do not have a complete >>>> list. However in future I could if you wish say ' nearly everybody except >>>> people like Alan Robock . . .' Perhaps in return you could in future >>>> distinguish the tropospheric salt and stratospheric sulphur SRM techniques >>>> from one another. >>>> >>>> By the way I do value your opposition. If we ever have to do >>>> geoengineering the process will be safer because of you. All I want is to >>>> have reliable equipment ready if it is needed in a hurry and all its >>>> effects well understood. I am a bit surprised that you are not making more >>>> of a fuss about figure 2b of your own paper in Atmospheric Chemistry and >>>> Physics and its effect on methane release. Where do your stand on PIOMAS >>>> Arctic volume predictions? >>>> >>>> Stephen >>>> >>>> >>>> >>>> >>>> On 22/03/2012 21:14, Alan Robock wrote: >>>> >>>> Dear Steve, >>>> >>>> In the article about your parliamentary hearing, it says: >>>> >>>> "Everybody working in geo-engineering hopes it won't be needed - but we >>>> fear it will be," said Prof Salter. >>>> >>>> This is incorrect, and I would like to request that you issue a >>>> statement to that effect. You are not speaking for me. And you need to >>>> ask everyone else working in this field, before you claim to speak for >>>> them. I personally fear that geoengineering will be used before all the >>>> potential effects are studied. This is quite different from fearing that >>>> it will be needed, because that implies that we know that it will be the >>>> only response society can take. Thanks. >>>> >>>> >>>> >>>> >>>> The University of Edinburgh is a charitable body, registered in >>>> Scotland, with registration number SC005336. >>>> >>>> >>>> >>>> -- >>>> 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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