My apologies, I misspelled Chylek in the email I sent a few moments ago. It is corrected below.
---- Dear Group, We wish to respond to comments made early regarding Canty et al., 2013. Motivated by the unsolicited review of our analysis, we addressed the issue of "double counting" in section 4.1.3 (Conditional Regression) of the final, published paper. The primary result of our study, that volcanoes cool but not as strong as some have suggested, is fully supported by Figure 1, FAQ5.1 of IPCC 2013. http://www.climatechange2013.org/images/figures/WGI_AR5_FigFAQ5.1-1.jpg Another paper that reached the same conclusion not yet mentioned in this thread was led by David Thompson (2009) and appeared in the Journal of Climate http://journals.ametsoc.org/doi/pdf/10.1175/2009JCLI3089.1 The primary conclusion of our study, that the decline in global mean surface temperature due to Pinatubo was considerably less than 0.5C, is not only supported by Thompson et al., 2009 and IPCC 2013 but also several more recent studies such as Marotzke and Forster, 2015 https://www.nature.com/articles/nature14117 as well as Chylek et al., 2014 http://onlinelibrary.wiley.com/doi/10.1002/2014GL059274/epdf Sincerely, Tim Canty and Ross Salawitch > On Fri, 2017-12-01 at 16:05 +0100, Guido Visconti wrote: > > Dear Alan > > > > > > This is what Wunderlich and Mitchell say in the conclusions > > > > > > A more robust indicator for the strengthening of the dynamically > > driven influence of the volcanic eruption > > > > is the characteristic winter warming over northern Europe (Shindell et > > al., 2004; Fischer et al., 2007). By averaging over > > > > the whole first year after the eruption we still could find a > > significant positive signal in northern Europe due to the winter > > > > warming. This means that the general decrease of the surface > > temperature due to the injected aerosols is overwhelmed by > > > > this dynamical effect at midlatitudes. This contributes to the fact > > that the strength of the radiative-driven cooling is still > > > > not completely determined. The less dynamically influenced tropical > > response to volcanic eruptions shows a general cooling > > > > mainly over ocean areas (Stenchikov et al., 2006). Nevertheless, > > considering the first 2 years after the eruption of > > > > Mt Agung and El Chichón no clear tropical cooling in both reanalysis > > and observation data is found. The model response > > > > to the eruptions shows a large uncertainty spread, suggesting a high > > dependence of the climate response on the atmospheric > > > > state during and after the eruption. > > > > > > Also these are the conclusion of Fujiwara eta al. > > > > > > The latitude-pressure distribution of El Chichón and Mount Pinatubo > > temperature response was quite similar at least among the recent four > > reanalysis data sets (JRA- > > > > 55, MERRA, ERA-Interim, and NCEP-CFSR) and between the 1979–2009 and > > 1958–2001 analyses. For the Mount Pinatubo eruption, tropical lower > > stratospheric warming and > > > > tropical upper tropospheric cooling were observed. For the El Chichón > > eruption, tropical lower stratospheric warming > > > > was observed, but tropospheric cooling was much weaker than the Mount > > Pinatubo case. For the Mount Agung eruption, > > > > JRA-55, ERA-40, and NCEP-1 showed Southern Hemisphere lower > > stratospheric warming centred at 40–30 S and > > > > 100–50 hPa, with an equatorial extension to 50 hPa. Thus, the Agung > > signal was asymmetric about the equator and very different > > > > from the El Chichón and Pinatubo signals.We suggest that this may be > > due to differences in the transport of volcanic > > > > aerosols (Sato et al., 1993). > > > > > > An this is what the abstract of Driscoll et al says > > > > > > 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. > > > > > > As for Hansen et al. > > > > > > Those second digits approximations are very suspicious as are the data > > from Newell and Weare that refers to just one station(I may be wrong) > > Not to mention the approximation on the optical depth. > > > > > > I know that is very hard to give up a golden egg hen but sometime we > > have to face the Matrix recommendation: welcome to the real world > > > > > > Guido > > > > > > > > > > > > > > > > Da: Alan Robock <[email protected]> > > Risposta: <[email protected]> > > Data: Fri, 1 Dec 2017 09:38:11 -0500 > > A: Guido Visconti <[email protected]>, > > <[email protected]> > > Cc: <[email protected]>, geoengineering > > <[email protected]> > > Oggetto: Re: [geo] VEI vs cooling > > > > > > > > Dear Guido, > > > > Yes, volcanic eruptions that inject SO2 into the stratosphere cool > > Earth and cause Northern Hemisphere winter warming in the first winter > > after tropical eruptions. Hansen et al. (1979) is correct, and Jim > > has been a pioneer in studying the effects of volcanic eruptions on > > climate. > > > > Canty et al. (2013) made a fundamental error in counting the cooling > > by volcanic eruptions twice, as I pointed out here: > > https://www.atmos-chem-phys-discuss.net/12/C10686/2012/acpd-12-C10686-2012.pdf > > > > Driscoll et al. (2012) diluted the volcanic signal by including many > > small eruptions and looking at two winters following each eruption. > > By looking at only large eruptions and one winter, we show a clear > > signal in: > > > > Zambri, Brian, and Alan Robock, 2016: Winter warming and > > summer monsoon reduction after volcanic eruptions in Coupled > > Model Intercomparison Project 5 (CMIP5) simulations. Geophys. > > Res. Lett., 43, 10,920-10,928, doi:10.1002/2016GL070460. > > > > and > > > > Zambri, Brian, Allegra N. LeGrande, Alan Robock, and Joanna > > Slawinska, 2017: Northern Hemisphere winter warming and summer > > monsoon reduction after volcanic eruptions over the last > > millennium. J. Geophys. Res. Atmos., 122, 7971-7989, > > doi:10.1002/2017JD026728. > > Fujiwara et al. (2015) find stratospheric warming after the three most > > recent eruptions, consistent with previous work. Why mention it? > > > > Wunderlich and Mitchell (2017) actually do find a positive NAO and > > tropical cooling after large eruptions, so I don't understand why you > > even mention that paper either. > > > > So you have brought up two papers that agree with Hansen et al. (1979) > > and conventional wisdom, and two with fundamental problems. > > Alan > > > > Alan Robock, Distinguished Professor > > Editor, Reviews of Geophysics > > Department of Environmental Sciences Phone: +1-848-932-5751 > > Rutgers University Fax: +1-732-932-8644 > > 14 College Farm Road E-mail: [email protected] > > Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock > > ☮ http://twitter.com/AlanRobock 2017 Nobel Peace Prize to ICAN! > > Watch my 18 min TEDx talk at http://www.youtube.com/watch?v=qsrEk1oZ-54 > > On 12/1/2017 4:08 AM, Guido Visconti wrote: > > > > > Hello all > > > > > > > > > but the eruptions really cool? Read the papers > > > > > > > > > Wunderlich, F., & Mitchell, D. M. (2017). Revisiting the observed > > > surface climate response to large volcanic eruptions. Atmospheric > > > Chemistry and Physics, 17(1), 485-499. DOI: 10.5194/acp-17-485-2017ù > > > > > > > > > Fujiwara, M., Hibino, T., Mehta, S. K., Gray, L., Mitchell, D., & > > > Anstey, J. (2015) Global temperature response to the major volcanic > > > eruptions in multiple reanalysis data sets. Atmospheric Chemistry > > > and Physics, 15, 13507–13518. > > > > > > > > > Canty, T., Mascioli, N. R., Smarte, M. D., & Salawitch, R. J. (2013) > > > An empirical model of global climate-Part 1: A critical evaluation > > > of volcanic cooling. Atmospheric Chemistry and Physics,13, 3997. > > > > > > > > > Driscoll, S., Bozzo, A., Gray, L.J., Robock, A. and G. Stenchikov > > > (2012) Coupled Model Intercomparison Project 5 (CMIP5) simulations, > > > of climate following volcanic eruptions, J. Geophys. Res., 117, > > > D17105, doi:10.1029/2012JD01760 > > > > > > > > > > > > > > > In view of these the paper by Jin Hansen et al. (Hansen, J. > > > E.,Wang,W. C., and A.A. Lacis, (1978) Mount Agung eruption provides > > > test of a global climatic perturbation. Science, 199, 1065-1068, DOI > > > 10.1126/science.199.4333. 1065) > > > > > > > > > should be at least withdrawn > > > > > > > > > Guido Visconti > > > > > > > > > > > > > > > > > > > > > > > > > > > > Il giorno 01 dic 2017, alle ore 06:41, Paul Beckwith > > > > <[email protected]> ha scritto: > > > > > > > > Hello Alan, > > > > > > > > For Mount St. Helens in 1980, wasn’t the main reason for the lack > > > > of climate impact the fact that the explosive energy was mostly > > > > directed horizontally as opposed to upwards, so that minimal > > > > sulfur amounts reached the stratosphere. I thought that there was > > > > significant sulfur released from the eruption, but that it mostly > > > > stayed in the troposphere. > > > > > > > > Sincerely, > > > > Paul > > > > > > > > -----Original Message----- > > > > From: [email protected] > > > > [mailto:[email protected]] On Behalf Of Alan Robock > > > > Sent: Thursday, November 30, 2017 11:27 PM > > > > To: [email protected]; geoengineering > > > > Subject: Re: [geo] VEI vs cooling > > > > > > > > There is a positive correlation, but VEI is not a good index. It > > > > is an estimate of the explosive energy, not the amount of sulfur > > > > injected into the stratosphere, which is what determines the > > > > climate impact. Mount St. Helens in 1980 was VEI 5, very > > > > explosive, but had little SO2 and no climate impact. See the > > > > discussion on pp. 11551-11553 of my paper, > > > > http://climate.envsci.rutgers.edu/pdf/RobockFree95JD00825.pdf > > > > > > > > Alan > > > > > > > > Alan Robock, Distinguished Professor > > > > Editor, Reviews of Geophysics > > > > Department of Environmental Sciences Phone: > > > > +1-848-932-5751 > > > > 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 > > > > ☮ http://twitter.com/AlanRobock 2017 Nobel Peace Prize to > > > > ICAN! > > > > Watch my 18 min TEDx talk at > > > > http://www.youtube.com/watch?v=qsrEk1oZ-54 > > > > > > > > On 11/30/2017 10:21 PM, David Appell wrote: > > > > > SRM people: > > > > > > > > > > Does a volcanic eruption's VEI correlate to the amount of > > > > > cooling it > > > > > will/can cause? > > > > > > > > > > David > > > > > > > > > > > > > -- > > > > 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]. > > > > To post to this group, send email to > > > > [email protected]. > > > > Visit this group at > > > > https://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 [email protected]. > > > > To post to this group, send email to > > > > [email protected]. > > > > Visit this group at > > > > https://groups.google.com/group/geoengineering. > > > > For more options, visit https://groups.google.com/d/optout. > > > > > > > > > > > > > > > ---------------------------------------------------------------- Timothy Canty, PhD. Associate Research Professor/2017 UGST Faculty Fellow Director of Undergraduate and Professional Masters programs Department of Atmospheric and Oceanic Science 3427 Atlantic Bldg University of Maryland, College Park, 20742 Office: 301-405-5360 Fax: 301-314-9482 ---------------------------------------------------------------- -- 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]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
