1. Contrailscience.com<http://Contrailscience.com>
2. What is clarity? 3. Where? When? I have never heard this claim before. Please show us the data. Alan Alan Robock, Distinguished Professor Associate Editor, Reviews of Geophysics Department of Environmental Sciences Phone: +1-848-932-5751 Rutgers University E-mail: [email protected]<mailto:[email protected]> 14 College Farm Road http://people.envsci.rutgers.edu/robock New Brunswick, NJ 08901-8551 USA ☮ http://twitter.com/AlanRobock On Jul 15, 2019, at 2:45 AM, Stephen Salter <[email protected]<mailto:[email protected]>> wrote: Alan 1. How can you tell the difference between clear weather and no contrails? 2. Do contrails affect weather clarity? 3. Is there a reason why it was the clearest of clear weather for 30 years? Stephen Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland [email protected]<mailto:[email protected]>, Tel +44 (0)131 650 5704, WWW.homepages.ed.ac.uk/shs<http://WWW.homepages.ed.ac.uk/shs>, YouTube Jamie Taylor Power for Change On 14/07/2019 15:51, Alan Robock wrote: See also https://www.nature.com/news/2008/081231/full/news.2008.1335.html for a discussion of several papers on this. Alan Alan Robock, Distinguished Professor Associate Editor, Reviews of Geophysics Department of Environmental Sciences Phone: +1-848-932-5751 Rutgers University E-mail: [email protected]<mailto:[email protected]> 14 College Farm Road http://people.envsci.rutgers.edu/robock New Brunswick, NJ 08901-8551 USA ☮ http://twitter.com/AlanRobock On Jul 14, 2019, at 8:47 AM, Alan Robock <[email protected]<mailto:[email protected]>> wrote: The reported warming after 9/11 was actually a change in diurnal temperature range. Kalkstein and Balling found that it was just clear weather and not lack of contrails. https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.pdf Alan Alan Robock, Distinguished Professor Associate Editor, Reviews of Geophysics Department of Environmental Sciences Phone: +1-848-932-5751 Rutgers University E-mail: [email protected]<mailto:[email protected]> 14 College Farm Road http://people.envsci.rutgers.edu/robock New Brunswick, NJ 08901-8551 USA ☮ http://twitter.com/AlanRobock On Jul 14, 2019, at 7:00 AM, Seb Eastham <[email protected]<mailto:[email protected]>> wrote: Hi John , Inconveniently, they do both. They reflect and scatter incoming solar radiation (cooling effect) but also absorb outgoing longwave (warming). At night they are purely warming, but during the day the net effect can be either - depending strongly on whether there are clouds beneath them (decreases cooling benefit), the surface albedo (sea is dark so contrail benefits are greater), and the surface temperature. Kärcher wrote an excellent review article in 2018 (Formation and radiative forcing of contrail cirrus) covering the degree of uncertainty in all this - since we have very poor records of total coverage and properties, the exact balance between warming and cooling is also highly uncertain. Regards, Seb On Sun, Jul 14, 2019, 08:40 john gorman <[email protected]<mailto:[email protected]>> wrote: The report that got me into this was a research paper showing that the lack of contrails just after 911 allowed a warming of the atmosphere. So I came up with an idea to increase and simulate the cooling effect of contrails. At the time I had never heard of the this group or the word geoengineering. I now see in a recent post that contrails warm the earth. Which is correct? John Gorman -- 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:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. 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/5d29a2ee.1c69fb81.57666.3e93SMTPIN_ADDED_MISSING%40gmr-mx.google.com<https://groups.google.com/d/msgid/geoengineering/5d29a2ee.1c69fb81.57666.3e93SMTPIN_ADDED_MISSING%40gmr-mx.google.com?utm_medium=email&utm_source=footer>. 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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