cc: Olga Solomina , Peter Lemke , jto@u.arizona.edu date: Mon, 27 Feb 2006 18:09:24 +0100 (MET) from: Georg Kaser subject: Re: IPCC Ch4.5 to: Keith Briffa Dear Keith, have many thanks. I am glad you can keep this. The paragraph looks fine for me although we had some comments on the Vincent findings saying: "I am not sure I agree with this statement. Vincent et al. (2005, cited in the chapter) guess a 25% precipitation increase in the 1760-1830 period compared to the 20th century average and this is based on a simple model (degree-days) to explain glaciers extent. However, Casty et al. (Temperature and precipitation variabiltiy in the european Alps since 1500, Int. J. Climatology, in press) find no such precipitation increase in the observations.The 2 results are thus in conflict. [Christophe GENTHON]" Does anyone know the Casty paper? Valerie may have an insight to this Inner French discussion. Sorry that I had not forwarded this to you earlier. Regards, Georg Georg Kaser ------------------------------------------------- Institut fuer Geographie Innrain 52 A-6020 INNSBRUCK AUSTRIA Tel: ++43 512 507 5407 Fax: ++43 512 507 2895 http://meteo9.uibk.ac.at/IceClim/CRYO/cryo_a.html On Mon, 27 Feb 2006, Keith Briffa wrote: > Georg > we have included the Oerlamans curve and modified a piece of text from your > original text . that is > > Oerlemanns (2005) has constructed a temperature history for the globe based > on 169 glacier-length records. He uses simplified glacier dynamics that > incorporate specific response time and climate sensitivity estimates for each > glacier. The reconstruction suggests that moderate global warming occurred > after the middle of the 19th century, with about 0.6 degree C warming by the > middle of the 20th century. Following a 25-year cooling, temperatures rose > again after 1970, though much regional and high-frequency variability is > superimposed on this overall interpretation. However, this approach does not > allow for changing glacier sensitivity over time, which may limit the > information before 1900. Analyses of glacier mass balances, volume changes, > and length variations along with temperature records in the western European > Alps (Vincent et al., 2005) indicate that between 1760 and 1830, glacier > advance was driven by precipitation that was 25% above the 20th century > average ,while there was little difference in average temperatures. Glacier > retreat after 1830 was related to reduced winter precipitation and the > influence of summer warming only became effective at the beginning of the > 20th century. In southern Norway, early 18th century glacier advances can be > attributed to increased winter precipitation rather than cold temperatures > (Nesje and Dahl, 2003). > > For now this is all we can manage and we are discussing the need to cut our > Chapter further - but this will at least remain > thanks > Keith > > At 16:16 27/02/2006, Georg Kaser wrote: >> Dear Olga and Keith, >> >> find attached the present state of chapter 4.5 on glaciers and ice caps. We >> have now entirely removed the MWP and LIA discussion and I hope you have >> been able to cover this. I also hope that you have been able to implement >> the Oerlemans temperature curve as we had agreed. If I have missed to >> supply you with anything I should have, please apologize and let me know. >> >> With best wishes, >> Georg >> >> Georg Kaser >> ------------------------------------------------- >> Institut fuer Geographie >> Innrain 52 >> A-6020 INNSBRUCK >> AUSTRIA >> Tel: ++43 512 507 5407 >> Fax: ++43 512 507 2895 >> http://meteo9.uibk.ac.at/IceClim/CRYO/cryo_a.html >> > > -- > Professor Keith Briffa, > Climatic Research Unit > University of East Anglia > Norwich, NR4 7TJ, U.K. > > Phone: +44-1603-593909 > Fax: +44-1603-507784 > > http://www.cru.uea.ac.uk/cru/people/briffa/ >