Hello All, A few comments following on from the valuable ones made by Adrian Tuck:-
The production of water clouds in the atmosphere requires more than effective cloud condensation nuclei, CCN. The atmosphere needs to be unstable, so that ascent of moist air, once initiated, will continue, the air will cool [because of expansion resulting from the reduced pressure] so the relative humidity increases. When it reaches 100% condensation occurs on suitable CCN, forming droplets which grow as they rise in the supersaturated environment of thewater clouds. The presence or absence of such clouds in a given region is much more likely to be governed by the meteorology, particularly the stability issue - as outlined above - than by the presence or absence of suitable CCN. Suitable CCN required for droplet formation are almost always present in the natural environment. The Marine Cloud Brightening MCB idea, first published in Nature in 1990, and followed by about 15-20 more detailed articles, involves generating seawater droplets - of specified, controllable flux and size - which are very effective as CCN. In my view, this is a much more reliable and promising way of enhancing the albedos of marine stratocumulus clouds, to produce a global cooling. Best wishes, John Latham. John Latham Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 Email: [email protected] or [email protected] Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 or (US-Cell) 303-882-0724 or (UK) 01928-730-002 http://www.mmm.ucar.edu/people/latham ________________________________________ From: [email protected] [[email protected]] on behalf of Dr. Adrian Tuck [[email protected]] Sent: 17 October 2013 13:19 To: Andrew Lockley Cc: geoengineering Subject: Re: [geo] Amine cloud brightening Not a new idea. Also, the reality is that cloud formation in the atmosphere will always involve a chemically complex mixture: Murphy, Thomson & Mahoney, Science, 282, 1664-1669 (1998) detected 46 different elements with a single particle technique (Particle Analysis by Laser Mass Spectrometry) in a million or so particles during 5 6 aircraft flights, with up to 10 elements in some particles. For proteinaceous material, see:- AMINO-ACID NITROGEN IN ATMOSPHERIC AEROSOLS - OCCURRENCE, SOURCES AND PHOTOCHEMICAL MODIFICATION Author(s): MILNE, PJ<http://apps.webofknowledge.com.iclibezp1.cc.ic.ac.uk/DaisyOneClickSearch.do?product=WOS&search_mode=DaisyOneClickSearch&colName=WOS&SID=U2ZTIf4E7SpTqSk6XUo&author_name=MILNE,%20PJ&dais_id=13371384&excludeEventConfig=ExcludeIfFromFullRecPage> (MILNE, PJ); ZIKA, RG<http://apps.webofknowledge.com.iclibezp1.cc.ic.ac.uk/DaisyOneClickSearch.do?product=WOS&search_mode=DaisyOneClickSearch&colName=WOS&SID=U2ZTIf4E7SpTqSk6XUo&author_name=ZIKA,%20RG&dais_id=10044524&excludeEventConfig=ExcludeIfFromFullRecPage> (ZIKA, RG) Source: JOURNAL OF ATMOSPHERIC CHEMISTRY Volume: 16 Issue: 4 Pages: 361-398 DOI: 10.1007/BF01032631 Published: MAY 1993 Times Cited: 51<http://apps.webofknowledge.com.iclibezp1.cc.ic.ac.uk/CitingArticles.do?product=WOS&search_mode=CitingArticles&SID=U2ZTIf4E7SpTqSk6XUo&parentProduct=WOS&parentQid=1&excludeEventConfig=ExcludeIfFromFullRecPage&parentDoc=44&REFID=12769016&alldbColName=WOS&colName=WOS> (from Web of Science) Cited References: 213<http://apps.webofknowledge.com.iclibezp1.cc.ic.ac.uk/CitedRefList.do?product=WOS&search_mode=CitedRefList&SID=U2ZTIf4E7SpTqSk6XUo&colName=WOS&parentProduct=WOS&parentQid=1&parentDoc=44&recid=WOS:A1993LB83200005&UT=WOS:A1993LB83200005&excludeEventConfig=ExcludeIfFromFullRecPage> [ view related records<http://apps.webofknowledge.com.iclibezp1.cc.ic.ac.uk/Related.do?UT=WOS:A1993LB83200005&refColName=WOS&parentProduct=WOS&parentQid=1&product=WOS&search_mode=RelatedRecords&SID=U2ZTIf4E7SpTqSk6XUo&colName=WOS&parentDoc=44&excludeEventConfig=ExcludeIfFromFullRecPage> ] [Citation Map] Citation Map Abstract: The presence of amino acids in atmospheric precipitation and aerosols has been noted for many years, yet relatively little is known about these or other nitrogen containing organic compounds in the atmosphere. Marine and continental rainwater analyses indicate that atmospheric aerosols, and subsequently atmospheric precipitation, may contain substantial levels of free and combined amino acids. The most likely source of amino N in the remote marine atmosphere appears to be the injection of proteinaceous material through the action of bursting bubbles at the sea-air interface or the long range transport from terrestrial sources. The capacity of these substrates to undergo photooxidation and photodegradation in the atmosphere to simpler species, such as ammonium ions, carboxylic acids, and for the S containing amino acids, oxidized forms of sulfur, has received little attention from atmospheric chemists. The photochemistry of covalently bound amino groups, particularly as found in peptides and amino acids, is discussed here with the purpose of summarizing what is known of their occurrence and their possible importance to atmospheric chemistry. Accession Number: WOS:A1993LB83200005 Document Type: Review Language: English Author Keywords: AMINO NITROGEN; AMINO ACIDS; PEPTIDES; PHOTOCHEMISTRY; ATMOSPHERIC CHEMISTRY KeyWords Plus: ELECTRON-SPIN-RESONANCE; PARTICLE-SIZE DISTRIBUTION; RADICAL-INDUCED OXIDATION; NEUTRAL AQUEOUS-SOLUTION; RATE CONSTANTS; SINGLET OXYGEN; SIMPLE DERIVATIVES; HYDROXYL RADICALS; MARINE ATMOSPHERE; ORGANIC-COMPOUNDS Reprint Address: MILNE, PJ (reprint author) [http://images.webofknowledge.com.iclibezp1.cc.ic.ac.uk/WOKRS511B5P1.01/images/expand.gif] UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,DIV MARINE & ATMOSPHER CHEM,MIAMI,FL 33149, USA. Publisher: KLUWER ACADEMIC PUBL, SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS Web of Science Categories: Environmental Sciences; Meteorology & Atmospheric Sciences Research Areas: Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences IDS Number: LB832 ISSN: 0167-7764 On 17 October 2013 12:56, Andrew Lockley <[email protected]<mailto:[email protected]>> wrote: Poster's note : appears off topic, but later discusses how amine release could be used for geoengineering purposes Original paper at http://www.nature.com/nature/journal/v502/n7471/full/nature12663.html http://www.independent.co.uk/environment/climate-change/cloudy-with-a-chance-of-climate-change-discovery-that-agricultural-practices-help-form-clouds-could-change-the-way-we-calculate-global-warming-8876474.html Cloudy with a chance of... climate change: Discovery that agricultural practices help form clouds could change the way we calculate global warming - Climate Change - Environment - The Independent A team of scientists led by a British academic has solved a long-standing enigma to explain how up to half the clouds in the sky are formed. And in finally cracking the problem of how planet-cooling clouds are conjured from what might seem to be thin air, the researchers found that humans play a significant role. It is a discovery that could fundamentally change our understanding of climate change, and may even mean experts have underestimated just how warm the planet will get over the next century. The mystery was that many clouds appeared in the sky even though there were no "seeds" – often just specks of dust – that must be present for water droplets to form in the air. But, writing in the journal Nature last week, researchers from the Cern laboratory in Switzerland described for the first time how a chemical soup of gas vapours can react to form the necessary tiny particles.To do so they had to build a chamber of "unprecedented cleanliness" at Cern in order to ensure they could work out exactly what was going on in the atmosphere."This is the first time that atmospheric particle formation has been reproduced with complete knowledge of the participating molecules," said Professor Jasper Kirkby, leader of the research team. "This is an important step forward, but we still have a long way to go before we fully understand the processes of aerosol formation and their effects on clouds and climate."The research showed that gases called amines – produced in large quantities as a result of farming cattle and other animals – can help form the seed particles when combined with sulphuric acid in the air. Breathe in air from a farm and it is likely you are getting a lungful of amines, as they come from the breakdown of proteins and can be found in animal slurry. Rotting fish gives off a particularly concentrated dose.Professor Kirkby, originally from Manchester, stressed it was possible that clouds could be produced in a similar way with sulphuric acid but with different kinds of vapours than amines. He said this newly discovered process would have to be factored into climate change models used by the Intergovernmental Panel on Climate Change (IPCC).The lack of knowledge about aerosols – particles suspended in the atmosphere – and their effect on clouds is widely recognised as the major source of uncertainty in predictions about global warming. "We have to understand how clouds have been changed by human activity or natural activity if we are to understand climate change in the 20th century and therefore have reliable projections in the 21st century," Professor Kirkby said.The global average temperature on land and sea rose by 0.85C from 1880 to 2012, the IPCC said in a major report last month. The fact that amines are produced by animal husbandry means that humans are responsible for a previously unknown cooling effect on the planet. So the overall man-made "forcing" of the climate – once greenhouse gases are taken into account – may actually be less than thought.And that could be bad news because, Professor Kirkby said, it suggested "the climate may be more sensitive than previously thought". "If there's been more cooling from aerosols than thought at the moment then this temperature rise will have resulted from a smaller forcing – or change – than previously thought," he said. "That would mean the projected temperatures this century for a doubling of carbon dioxide may be bigger than current estimates."In its report the IPCC said that temperatures could increase by between 0.6C and 4C by 2100 depending on carbon emissions. The latter figure would cause sea levels to rise substantially and increase the frequency of storms, droughts and other hazardous weather. A temperature rise of more than 2C above pre-industrial levels is seen as the point at which the effects become dangerous.The study suggests a possible way scientists could create clouds to help cool the Earth, although such geo-engineering is controversial. Amines are also used in carbon-capture at power stations and factories, so this might be a spin-off benefit.Gerald North, professor of atmospheric sciences and oceanography at Texas A&M University in the US, welcomed the research, saying that aerosols had been "really very poorly understood". He described the idea that climate models may have been underestimating global warming over the next century as "very interesting", but also warned of the need for more research on the subject.Professor North suggested the discovery might offer some form of hope for the planet. "We don't know if these amines are increasing the same way that carbon dioxide is increasing," he said."If they were increasing at the same rate, maybe everything would be fine! But we don't know."Piers Forster, professor of physical climate change at Leeds University, said people had previously tried to work out the cloud-making process, speculating about ammonia, cosmic rays and other factors."If you get amines being produced in parts of the world that are very pristine, this could have a direct effect on clouds," he said. While the research would help improve climate models, he said he doubted it would alter temperature projections significantly. -- 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 [email protected]<mailto:geoengineering%[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out. -- *************************************************** 'ATMOSPHERIC TURBULENCE: A Molecular Dynamics Perspective'. Oxford University Press, 2008. ISBN 978-0-19-923653-4. http://www.oup.com/uk/catalogue/?ci=9780199236534 *************************************************** -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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