Dear Peter, Thank you very much for that very positive contribution. Most of the "technologies" we are talking about have been well tested and proven to work. And the questions I asked are already being answered!
We all know that for maintaining the sea ice, interventions will be required on a very large scale. The problem with many technologies is their ability to scale - but, given resources and something like a war effort, it is possible to imagine ice thickening done the necessary scale to produce a significant reduction in the risk of the Arctic Ocean suddenly getting locked into a low-ice state. John On Sat, Jan 3, 2015 at 4:57 PM, Peter Flynn <peter.fl...@ualberta.ca> wrote: > A few thoughts: > > > > 1. This is not novel technology. Ice bridges, roads and islands have been > built with both salt and freshwater. Thickened sea ice from ocean water has > been used to make roads and both floating drilling platforms and platforms > thick enough to anchor on the seabed in the shallow Beaufort Sea. For a > sample reference, one of many, see > > > > > http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCkQFjAA&url=http%3A%2F%2Fpubs.aina.ucalgary.ca%2Farctic%2FArctic33-1-168.pdf&ei=ehaoVJicAoKmNq2VhNgG&usg=AFQjCNH9gFxqWhBtkVOQIQ-c6lm23Q7daw&bvm=bv.82001339,d.eXY > > > > 2. Rapid formation of ice is enhanced by spraying a fine mist into the air > (many who ski will have seen this done at ski hills). This is energy > intensive, but could be used to accelerate the creation of sea ice in open > water in the winter. > > > > 3. Simple low lift pumping of water onto the surface is the technique used > in making ice bridges and road in the north. Very thick structures are made > in weeks. > > > > 4. Andrew has expressed a concern about the formation of brine “lakes” on > the top of ice if the concentrated brine does not find its way through the > ice. (Brine is rejected into the ocean as natural sea ice forms at the > bottom of an ice sheet, and sea ice tends to have many micro-channels.) Two > thoughts. Any attempt to enhance the formation of sea ice would start with > a small scale demonstration, and the brine question could be easily > resolved. Second, what if brine does form on the surface? If the ice is > going to melt anyway, one is left with sea water either way. > > > > 5. I think that adding anything to ice (like sawdust or straw) vastly > complicates. First, it raises ecological questions, and second, as Andrew > points out, the logistics are terrible. In this case I personally lean to > “keep it simple”: just pump the water to surface to enhance heat transfer > to the air during the cold winter. > > > > 6. Many years ago a graduate student and I did a conceptual evaluation of > enhancing sea ice for a different purpose, to sustain the North Atlantic > Deep Water (NADW) current that is the offset of the gulf stream. We > envisioned that both spray and low lift pumping would be used on a massive > scale to create one Sverdrup (10^6 m^3 per second) of downward current. The > spray would hasten the formation of new sea ice, which would then be > thickened by low lift pumping. The melting of this ice in the spring would > enhance NADW, since a downflowing current in the North Atlantic requires > both salinity and temperature. Hence we presumed that the surface ice > created retained the brine/salt, but we noted that this was a key research > question. Our work is in Zhou and Flynn, Climatic Change (2005) 71 203-220. > I would be happy to forward a copy to anyone interested. > > > > 7. Either way, as Andrew notes, experimentation on a small demonstration > scale would be helpful in resolving questions. I think it is important to > note that such a demonstration would be using well proven past technologies > that have been used in both salt and fresh water in order to answer > questions specific to a sea ice enhancement project. > > > > Peter Flynn > > > > Peter Flynn, P. Eng., Ph. D. > > Emeritus Professor and Poole Chair in Management for Engineers > > Department of Mechanical Engineering > > University of Alberta > > peter.fl...@ualberta.ca > > cell: 928 451 4455 > > > > > > > > *From:* geoengineering@googlegroups.com [mailto: > geoengineering@googlegroups.com] *On Behalf Of *Andrew Lockley > *Sent:* January-03-15 3:42 AM > *To:* John Nissen; geoengineering > > *Subject:* Re: [geo] Watch "Integrated Assessment of Geoengineering > Proposals…" on YouTube > > > > It's not so simple.... > > 1 the Arctic is basically a small continent, so scales are enormous > 2 adding straw, etc is a great idea, but logistics are horrific > 3 brine rejection is a big issue. It needs to either drain through the ice > (needing drilling or pumping) or it will pond on the surface or as > inclusions (probably both) the resulting ice is unnatural and unstable, as > it's darker and more prone to fracture. > 4 it may be far easier to use icebreakers, which expose a lot of clear, > dark water. They also don't have a brine rejection issue. > 5 thickening key areas of ice may be far more effective than general > thickening, as most ice loss is ultimately wind driven. You need only stop > the wind clearance, and you stop the loss (to a point) > > Experiments are needed before advocacy. > > A > > On 3 Jan 2015 10:35, "John Nissen" <johnnissen2...@gmail.com> wrote: > > Hi Peter, > > > > Thanks for this important contribution to the discussion on cooling the > Arctic. We need to throw as many practical techniques as we can at this > problem, since saving the sea ice is so vital. And speed is vital - so we > should start pumping this winter! > > > > But there are some questions about the method. Does one need to use fresh > water, or will sea water suffice? Should one spray the water to produce > snow for wider cover, or can one simply pour the water onto the ice? Is > there a pattern one should produce, e.g. ridges to form a hexagonal > lattice? Could one mix the water with straw, sawdust or other organic > material to produce stronger ice (called "pykrete") and make the structure > even stronger and more resistant to melting and break-up in the spring. > Where should one most concentrate ones efforts - should it be at the > anticipated edge of the ice where break-up would be most telling in summer? > > > > May I invite others to join in this debate? We need rapid resolution of > these and other questions if we are to make a convincing proposal for > action in the face of rapidly disappearing sea ice. Time is running out. > > > > Cheers, John > > > > > > > > On Sat, Jan 3, 2015 at 12:48 AM, Peter Flynn <peter.fl...@ualberta.ca> > wrote: > > Cooling the Arctic will drop the temperature and get to the fundamental > cause of shrinking ice: rising temperature. > > > > In the meantime, the formation of ice can be vastly accelerated by a > simple and well demonstrated technology: pump water on top of ice during > the winter. The fundamental concept is that there is plenty of “cold” in > the winter, one simply gets around the insulating impact of the ice itself > (in nature, incremental sea ice forms at the bottom of the sheet). > > > > Spray technologies, energy intensive, have built ice islands for drilling > platforms in one season that are 8 meters plus in thickness; this is much > like making “snow” on ski hills. Ice bridges are typically built with low > energy intensity: just pump water on top of existing ice. > > > > One merit of this approach is that it can be instantly stopped if any > unanticipated negative impact arises, reducing the fear factor in the > uninformed. > > > > Making sea ice doesn’t address the rising temperature itself other than by > restoring the albedo of the ice cover itself, but it does sustain the ice. > I think it is a good companion to temperature/insolation modification > schemes. > > > > Peter Flynn > > > > Peter Flynn, P. Eng., Ph. D. > > Emeritus Professor and Poole Chair in Management for Engineers > > Department of Mechanical Engineering > > University of Alberta > > peter.fl...@ualberta.ca > > cell: 928 451 4455 > > > > > > > > *From:* geoengineering@googlegroups.com [mailto: > geoengineering@googlegroups.com] *On Behalf Of *John Nissen > *Sent:* January-02-15 8:50 AM > *To:* bobbywood2...@gmail.com > *Cc:* Alan Gadian; Stephen Salter; geoengineering > *Subject:* Re: [geo] Watch "Integrated Assessment of Geoengineering > Proposals…" on YouTube > > > > Dear Rob, > > This is an extremely relevant discussion for any attempt to cool the > Arctic in order to halt sea ice retreat. (There is strong evidence that > the retreat is already having an effect on N Hemisphere climate due to jet > stream disruption, so a strong argument to try cooling the Arctic ASAP.) > > The two main approaches being considered are (i) to produce a reflecting > stratospheric haze at mid to high latitude and (ii) to brighten marine > clouds (MCB) in the troposphere over the North Atlantic and North Pacific. > In both cases the aim is to cool surface water flowing into the Arctic and > thereby slow sea ice melt and allow it to reform more easily. Much of the > surface water at higher latitudes (between about 50N and 70N) finds its way > into the Arctic. About 10% of the world's freshwater flows in the Arctic > Ocean. > > Most of your discussion has involved consideration of MCB, creating the > cloud condensation nuclei (CCN) from ships. Since there are so many > unknowns about the effectiveness, couldn't we have some useful experiments > from aircraft, or has this been done already? For example, you point out > that turbulence changes could reduce or enhance the initial enhancement - > and if it is a reduction this could be showstopper. > > Two further approaches for cooling the Arctic involve clouds: (iii) cloud > removal to increase outgoing thermal radiation, and (iv) cloud seeding to > produce fresh snow and thereby increase surface albedo on a regional > scale. In both these cases, we need to test the production of CCN from > aircraft and monitor effectiveness. > > Could you envisage a crash programme for testing of these various > approaches, to see which is most appropriate and effective in different > locations, at different times of year and under different circumstances > (existing cloud conditions, etc)? Has anything like this been done already? > > > > Cheers, John > > > > > > On Thu, Jan 1, 2015 at 4:47 PM, Rob Wood <bobbywood2...@gmail.com> wrote: > > A straightforward way to prevent plume sinking (if indeed it turns out to be > undesirable for particle dispersion), is to heat the stack. This happens > already on all cargo ships. > > > > I don't believe that coagulation will be a showstopper although experiments > will be necessary to confirm this because coagulation depends on the exact > size distribution and charging and this cannot be predicted from modeling > alone. Some degree of charging may well occur (not my expertise) but this > will likely depend on the spray method. Effervescent spray atomization (see > Cooper et al. article in Phil Trans 2014 special issue), does not seem to > make a lot of charged particles. > > > > Observations show that shiptracks are rarely observed in boundary layers > deeper than 1km. Globally, most stratocumulus occurs in PBLs deeper than > this. But shiptracks themselves (although highly visible) are not necessary > for MCB to work. Greater dispersion in the subcloud layer prior to ascent > into the stratocumulus deck in the intermittently coupled layer above, might > increase efficacy by producing a more evenly distributed droplet > concentration enhancement (Stephen alluded to this). > > > > That said, I disagree that the albedo enhancement required (e.g., to offset > CO2 doubling globally, i.e., about 4 W/m2) is small. Only 20% of the planet > has clouds that may be seedable, so the solar reflection of seeded clouds > would need to be enhanced by >20 W/m2 (this number being generous because it > is highly unlikely that uniform seeding is possible). This is about one fifth > to one quarter of typical cloud albedo. > > > > More important than whether the human eye can detect the brightening, is that > spatial albedo enhancement gradients, and changes to the condensate amounts > due to e.g. drizzle suppression, will drive turbulence changes and also > regional scale circulation changes that produce cloud adjustments that could > reduce or enhance the initial enhancement. For example, it is known that on > average, condensate amounts in shiptracks are lower than in surrounding > clouds (e.g. Coakley and Walsh 2002, Chen et al. 2014) because reduced > precipitation in the track leads to stronger turbulence which drives greater > entrainment of dry free tropospheric air that thins the cloud layer. Ackerman > et al. (2004, Nature) first noticed this in large eddy models, and I wrote a > paper that attempted to explain this behavior with a simple model (Wood, J. > Atmos. Sci. 2007). These responses are difficult to capture in climate models > as they depend upon subgrid scale processes that are poorly represented in > models with re > > solutions greater than a few hundred meters horizontal and a few meters in > the vertical. A big challenge. This *might* be the biggest showstopper of all > for MCB. > > Regards > > Rob > > > > On 1/1/2015 4:36 AM, Alan Gadian wrote: > > > Stephen, > > I am afraid I cannot comment on the electrification, but I would like to > emphasise the dynamics again. WRF (and WRF Chem ) can be driven either by > an observed real data, or in an idealised WRF - LEM form ( with no BL > parameterisation scheme) driven from an atmospheric profile > > In all LEM modelling of Sc, an important feature is always entrainment and > mixing. The horizontal and vertical velocities and the "rolls" or > "eddies" are critical in this. If there is a decoupled layer near the > surface, for example, as is sometimes / often observed then this will > critically affect the dispersion. I am still uncertain what was run in the > WRF chem simulation, what BL scheme was used in the IGAP runs, but the > argument I am proposing was that the velocity structure is unlikely to > be correct, unless actually verified with observations. > > I am trying the think of examples. Yamaguchi & Feingold , 2014, show the > changes in turbulence patterns, Wang and Fiengold (2009) and other work > including that of Wood ( not mentioned as he is part of this discussion) > show examples of this importance of the turbulence and eddies. > > I know that volcanoes are completely different, and this work is not at > the required resolution for SC clouds, but the attached poster, probably > without video, is some work that we did. We had to run WRF in LEM mode to > get anywhere near the correct eddy structures for the near volcanic plume > eddies. Again looking at the high resolution modelling work of AndrejczuK > (some of which Rob was again involved with), the role of the interaction > between the dynamical eddy structure and the microphysics and latent heat > exchange is crucial. > > Thus again, I feel that there are a lot of uncertainties in the modelling > work, and the only way to see if MCB works is to do an experiment > > Alan Gadian > > > > > > On Thu, 1 Jan 2015, Stephen Salter wrote: > > Hi All > > The words 'charge' and 'electrostatic' do not appear in Stuart et 2013. > People cleaning oil tanks in the 1960's found the painful way that its is > difficult NOT to generate charge, see > http://www.infostatic.co.uk/Papers/TankWashingRisks.pdf . There are at > least two ways by which we can control charge. > > The Stuart paper used a size distribution of 100 size bins, spaced > logarithmically between 10 nm and 10 μm in wet diameter rather than > mono-disperse spray. This is a range of 1000:1. I hope to keep within > 20%. Coagulation requires a relative velocity between drops. Viscous > forces are very large at sub-micron dimension. Particles will behave like > sand in honey. Small scale turbulence will tend to vary the velocity of > particles but while the Stokes drag force goes with the first power of > diameter the mass resisting acceleration goes with the cube. If there is > a > wide range of drop diameters, local turbulence will produce much larger > range of relative velocities. It would be useful to know coagulation > rates > for narrow ranges of drop diameter. > > In my paper on the detection of small contrast changes I assumed a loss of > 50% which would not be a show stopper. > > In figure 2 of of the Stuart paper there is no sign of any initial drop > due > to evaporative cooling. > > Stephen > > > Emeritus Professor of Engineering Design. School of Engineering. > University > of Edinburgh. Mayfield Road. Edinburgh EH9 3JL. Scotland s.sal...@ed.ac.uk > Tel +44 (0)131 650 5704 Cell 07795 203 195 WWW.see.ed.ac.uk/~shs YouTube > Jamie Taylor Power for Change > > On 01/01/2015 02:48, Alan Gadian wrote: > Rob, > I agree here with you. With LEM modelling with WRF Chem, the bdy > layer schemes can be very diffusive. Ignoring the electrostatics > charge element, I am concerned that the PDFs of the vertical > velocities are critical. From experience 20m is not good enough > resolution in the vertical. How does the model cope with changes in > cloud droplet number, as seen in andrejczuk (2012 aNd 2014) . The > vocals profiles provide data on the BL dynamical profiles, and I fear > with the wef chem LEM results, the dynamics and hence the dispersion > are inadequately represented. WRF Chem is about 20 times slower than > WRF without the chemistry package, and thus the representation of the > dynamics has to be compromised for the inclusion of the chemistry. I > would like it clarified about how these results compare with > observations. > > The papers of Andrejcuck provide a surprisingly efficient and rapid > dispersion, and compare reasonably well with observations. > > Alan > > > T --- Alan Gadian, NCAS, UK, ( sent from a mobile device ) Email: > a...@env.leeds.ac.uk or alan...@gmail.com > Tel: +44 / 0 775 451 9009 or +44 / 0 113 343 7246 > T --- > > On 31 Dec 2014, at 23:46, Rob Wood <bobbywood2...@gmail.com> > <bobbywood2...@gmail.com> wrote: > > Dear All, > > I think that some degree of coagulation given such > localized point sources of large numbers of particles is > inevitable, as shown in the paper by Stuart et al. (2013). > This will also be the case with charged particles. > Nevertheless, I don't think that this is necessarily a > fundamental limitation. After all, shiptrack formation, > where even larger numbers of particles are produced, still > occurs. Coagulation must be considered in the > calculations. That said, in our recent paper (Connolly et > al. 2014), we found significant albedo enhancement in a > parcel model even with quite broad size distributions. The > optimal median particle size becomes smaller as the size > distribution spread broadens (e.g. from coagulation). For > broader distributions typical of those produced in lab > tests, the optimal median droplet diameters need to be > somewhat smaller than 0.1 micron. > > I tend to agree with Stephen that near-surface spreading > due to initial negative buoyancy from evaporation of water > from the small seawater droplets may not necessarily be a > tremendous problem for the reasons he states. This has not > yet been considered in any model that I know of, but could > easily be done with large eddy models. > > Rob Wood > > > On 12/30/2014 8:35 AM, Stephen Salter wrote: > Hi All > > Piers Forster's concern in his video about spray > coagulation would be reduced if his model had used > mono-disperse drops with an electrostatic charge as > specified in our 2008 paper on sea-going hardware. > > His concern about detecting the effectiveness is > because the cloud contrast change needed to save > humanity is below the detection threshold of the > human eye. However contrast can be enhanced by the > superposition of satellite aligned images. I have > previously circulated some to this group and hope > that the idea will give quantitative results in a > few days. > > The picture of spray plumes shown in box 3 of his > IAGP practicalities note must have been using warm > air from a chimney. Depending on the temperature > and relative humidity of the surrounding ambient air > there will be several degrees of temperature drop > due to the latent heat of evaporation. The increase > of density will lead to a rapid fall of the cooled > air which will spread out over the sea surface like > a spilt liquid until it has been warmed by the large > area of contact with sea. You can show this fall and > dispersion very cheaply with a pond fogger, £19.99 > from Maplin. We want this dispersion because a low > dose over a large area is more effective than a high > point dose. > > Forster seems to be ignoring completely the idea of > coded modulation of CCN concentration in climate > models even though the satisfactory operation was > demonstrated by Ben Parkes doing a PhD in Forster's > own Department at Leeds in 2012. This might allow us > to get an everywhere-to-everywhere transfer function > of marine cloud brightening and win-win result with > more rain in dry places and less in wet. The high > frequency response means that we can give a tactical > spraying based local day-to-day observations. > > It is a puzzle that the Parkes thesis has, yet > again, vanished from the Leeds University website. > > Stephen > > > > Emeritus Professor of Engineering Design. School of > Engineering. University of Edinburgh. Mayfield Road. > Edinburgh EH9 3JL. Scotland s.sal...@ed.ac.uk Tel > +44 (0)131 650 5704 Cell 07795 203 195 > WWW.see.ed.ac.uk/~shs YouTube Jamie Taylor Power for > Change > On 28/12/2014 20:03, Andrew Lockley wrote: > > Integrated Assessment of Geoengineering > Proposals…: http://youtu.be/FFjzzfCLCqw > > Poster's note : I personally have found it > very difficult to access and appraise the > science behind the IAGP project. Despite this, > a vast amount of publicity has been obtained > for the project. I think the IAGP team could > do more to encourage early, in-depth access to > their material, particularly bearing in mind > the huge media interest. > > -- > 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 > http://groups.google.com/group/geoengineering. > 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 > http://groups.google.com/group/geoengineering. > For more options, visit > https://groups.google.com/d/optout. > > > 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 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 > http://groups.google.com/group/geoengineering. > 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 http://groups.google.com/group/geoengineering. > 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 http://groups.google.com/group/geoengineering. > 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 http://groups.google.com/group/geoengineering. > 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 http://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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