cc: Brazdil Rudolf , Reinhard Boehm , "'Petr Dobrovolny'" , P.Jones@uea.ac.uk, Juerg Luterbacher , Jucundus Jacobeit , schrier@knmi.nl date: Tue, 17 Jun 2008 17:29:23 +0200 from: Petr Dobrovolny subject: Re: AW: AW: Central European temperature reconstruction to: Anders Moberg Dear colleagues, 1) we made some cross-checking of GER, CH and CZ document. indices on seasonal level only - I agree with Rudolf to stay on seasonal level only. 2) Average instr. CE series - my experience is - the more stations the better. Of course it is necessary to do some mutual comparison. I can do it next days with the set of stations suggested by Anders. So - I vote for including Austrian stations also. Best regards Petr Anders Moberg napsal(a): > Dear Rudolf, > > cc. all > > Some quick responses: > > 1. Yes, the monthly series are on the discrete scale from -3 to +3 for > each country. But - as we are averaging CH+DE+CZ, we actually have a > scale from -9 to +9 even for the monthly series (in years when all > countries have data, which is not always the case - but mostly we have > data from at least two countries). I think this speaks for producing > the monthly resolution. The paper can focus on seasonal resolution, > but we could anyway produce monthly series and add as 'additional > supplementary data'. > > 2-3. Yes, as we will use documentary data only for CH+DE+CZ, it is > natural to use instrumental data also for these three countries. > However, Austria nicely 'fills in' a geographical 'gap' between CH and > CZ. In addition all the EI-corrections are based on Austrian > measurements. This speaks for the use of CH+DE+CZ + AU for the > instrumental series. > > 4. Yes, it is very good if Petr can construct homogenised Prague data > separately for JFMA > > cheers, > Anders > > Brazdil Rudolf skrev: >> Dear Anders, dear colleagues, >> it is really great that also other colleagues are now involved in our >> discussions related to preparation of CE article for SI CC. There is >> no doubt that possibility to work with homogenous data significantly >> improves our possibilities and results. We spent with Peter a lot of >> time trying to homogenise Prague and Rapp series and it was done on >> seasonal and annual levels. Of course, in the situation we have also >> some German data available it is better to calculate any new German >> series and we can try to look once again on Prague data. But we >> should not forget the original aim of our paper fo SI CC - i.e. >> reconstruction of CE temperatures based on documentary and >> instrumental data since 1500. In this connection we need instrumental >> data for calibration/verification of documentary data and factual >> extension of instrumental data to AD 1500. In connection with this I >> propose following: >> 1) for supposed article in SI CC present results only on seasonal and >> annual level - working with documentary data on monthly level is >> biased by higher uncertainties than in case of seasons (e.g. >> resolution - for monthly indices you have only scale -3 to +3, but >> for seasons -9 to +9, we did not cross-checked interpretations of >> indices on the monthly level etc.) >> 2) if we have documentary data only for D, CH and CZ, then >> corresponding "CE" series should be really calculated only from >> series of these 3 regions >> 3) in case we would like to have real CE temperature series, then we >> should include not only Austrian data, but also Polish, Slovakian a >> Hungarian, how is usually Central Europe geographically taken >> 4) as mentioned by Peter, we are able to homogenise monthly Prague >> temperatures for JFMA for Juerg. >> With best regards, >> Sincerely >> Rudolf >> >> Anders Moberg napsal(a): >> >>> Dear Reinhard, Rudolf, Petr, Phil, Juerg, Jucundus, Gerard >>> >>> First of all; thanks, Reinhard, for this additional info. You >>> certainly don't need to convince me - I am already convinced that >>> your EI-corrected versions are better than the non-corrected >>> versions. This is certainly a step in the right direction. >>> >>> And good to have Phil onboard this little email conversation! It was >>> quite a time ago since we did some real work together. Phil; to make >>> a long story short - all you need to know at the moment, is that we >>> (Petr, Rudolf and others) aim at developing temperature series (at >>> least seasonal, but monthly are possible) for Central Europe back to >>> 1500 based on documentary evidence from Switzerland (Pfister), >>> Germany (Glaser) and Czech Republic (Petr, Rudolf), calibrated by >>> means of linear regression against long instrumental records over a >>> period overlap, and then using standard verification statistics plus >>> some additional work to modify the error bars to take into account >>> changes in expressed population signal over time. The calibrated >>> documentary series will then be used to extend the instrumental >>> record back in time. This is where Reinhard's new EI-corrected data >>> come in! >>> >>> I also put Juerg, Jucundus and Gerard on this email, as a >>> continuation of the discussions we had yesterday here in Ascona. >>> >>> Since yesterday, I had a look in the Rapp report from 2000. I just >>> realized (and Petr just 'discovered' the same thing independently, >>> as he just wrote that in an email to me) that Rapp's "German" series >>> for the period 1761-1890 actually is an average of De Bilt, Berlin, >>> Wien, Basel!! Obviously, we cannot and should not use the Rapp >>> series for our current work. I suggest instead the following >>> appropach, which is slightly different compared to what Petr, Rudolf >>> and I have been talking about recently: >>> >>> We construct one temperature series per country (Switzerland, >>> Germany, Czech, Austria), and then simply average the four country >>> series together to form a Central European temperature series. Voilá! >>> >>> The CH component could be an average of Basel, Bern and Geneva. >>> The DE component could be an average of Hohenpeissenberg, Karlsruhe, >>> Munchen, Regensburg and Stuttgart. >>> The AU component could be an average of Innsbruck, Kremsmuenster and >>> Wien. >>> The CZ component could consist simply of Prague, but homogenized >>> against appropriately chosen nearby stations in the new EI-corrected >>> dataset. >>> >>> Some questions: >>> >>> 1. Can any of you figure out a significantly better way to construct >>> a CE-average for the purpose of calibration and combination with >>> documentary data from CH+DE+CZ? Perhaps some of you would advocate >>> an unweighted average of all (or selected) individual stations, >>> rather than constructing four country series and then average? >>> >>> 2. Reinhard, you know most about all the individual EI-corrected >>> station records; Are they all of equal quality? Or should some >>> station(s) be excluded for data quality reasons? >>> >>> 3. Petr, would it be possible for you to homogenize the Prague >>> series along the lines suggested above? >>> >>> 4. We (Petr, Rudolf and I) have had some internal discussions as to >>> whether we should aim at reconstructing seasonal or monthly >>> temperatures. Petr advocates seasonal series. I rather think that, >>> because it is actually possible to construct monthly series back to >>> 1500, we should produce monthly series for the whole period. We can >>> of course also produce separately calibrated series for the >>> traditional seasons (DJF, MAM, JJA, SON) plus the additional JFMA >>> winter/spring season (for comparison with Stockholm) and also annual >>> mean series, in order to get the error bars for the seasons being >>> constructed directly for the seasonal averages. I cannot find any >>> particular reason why we should not produce monthly series. Even if >>> they might have poorer quality than the seasonal ones, this will be >>> accounted for by the error bars. For me, it is not much more work to >>> do 12 monthly series + 5 seasons + 1 annual series compared to doing >>> only the seasonal and annual cases. We can of course not discuss all >>> monthly series in detail in the paper, but we can show them all and >>> 'deliver' the data. >>> >>> Looking forwards to hear your viewpoints, >>> >>> cheers, >>> Anders >>> >>> >>> >>> Reinhard Boehm skrev: >>> >>>> Dear Anders, Rudolf and Petr, >>>> >>>> First some additional information regarding Anders' questions: >>>> >>>> Yes, everything is based on the only existing evidence of a multiyear >>>> comparison between a preserved original early instrumental site and >>>> a modern >>>> one. I would be happy if we could find additional information but >>>> it seems >>>> that Kremsmünster is unique (at least in the GAR I am quite sure >>>> about it). >>>> >>>> The second thing we did was to develop two other "correction >>>> models" for NNW >>>> and N-orientation (the Kremsmünster EI-site Kremsmünster is orientated >>>> towards +30°. Yesterday's new version of the paper-draft tells you >>>> more >>>> about that. It is quite a simple "model" but with the existing >>>> information >>>> we cannot do better I believe. >>>> >>>> Then we intensively studied metadata and could identify quite a lot >>>> of the >>>> three relevant infos we needed for the majority of the EI-sites: >>>> 1) Height above ground (less important for EI-correction of monthly >>>> means as >>>> argued in the paper draft, but interesting perhaps for future >>>> attempts on >>>> daily extremes which should be more sensitive to this parameter >>>> 2) Orientation of the site. This allowed for allocating the single >>>> sites >>>> (sunperiods) to one of the three correction models: -5 to +5° was >>>> defined to >>>> be N-orientation model, <-5° to NNW and <+5°NNE >>>> 3) The contemporarily used algorithms for means calculation >>>> >>>> You find the complete collection of metadata and the finally chosen >>>> correction models on the attached xls-file >>>> >>>> Finally (this is not yet written in the paper draft, but is implied >>>> in the >>>> ppt-file through the Regensburg-example) we applied for those cases >>>> with >>>> sufficient metadata information the individual correction models >>>> station by >>>> station (and sometimes subperiod per subperiod, applied "estimated >>>> correction models" in unsecure cases (e.g. based on the guess that >>>> similar >>>> equipment and habits for means calculation ma be assumed in >>>> stations managed >>>> by the same organisation or being in the same country. The >>>> remaining (few) >>>> cased with insufficient information were at last adjusted to the >>>> regional >>>> mean neighbouring ones with the usual proceeding when homogenising >>>> without >>>> metadata. >>>> >>>> Finally what we did not (could not) do was: >>>> >>>> Accounting for different latitudes (within our region I believe >>>> this to be >>>> of minor importance, so I would warn to overstreching the >>>> Kremsmünster-evidence too much, e.g. to the north (where insolation >>>> effects >>>> maybe stronger in summer mornings and evenings) or to the south >>>> (where the >>>> astronomical preliminaries tend to cause less problems, but maybe the >>>> climatological ones (more sunshine in summer) tend to cause more) >>>> >>>> Taking into account heat storage in the measuring walls when >>>> developing the >>>> NNW- and th N-correction models. Also for this we did not really >>>> find the >>>> necessary information on wall thicknesses, materials, colours >>>> etc... All in all I think we have done a step into the right >>>> direction. You will >>>> learn from the remaining part of the paper (I hope to be able to >>>> finish >>>> soon, but there are also other obligations) that the resulting >>>> EI-corrected >>>> records fit better to treering-reconstructions, have less >>>> difficulties to >>>> explain the high glacier extensions in the Alps in the first part >>>> of 19th >>>> century, reduce the previously existing strong difference of annual >>>> temperature cycle between the 19th and the 20th century (this is >>>> one of >>>> Phil's arguments in favour of doing the corrections), it is in better >>>> agreement with some longterm historic model runs (RIC from the >>>> GKSS-people >>>> for example) although the different solar forcing curves (mentioned >>>> in the >>>> introduction)are ambiguous (Lean, 200 is in favour of a "cold >>>> version, Bard >>>> et al., 2000) tells a story of quite strong solar forcing before >>>> the decline >>>> in the 1910s). The high elevation ice cores from the Monte Rosa Region >>>> (Colle Gnifetti)also provide two different informations, mineral dust >>>> content tending towards a cooler (EI-corrected) version, stable >>>> isotopes >>>> more towards a warmer one near 1800. The existing few infos on >>>> high-elevation alpine lake sediments tend more to tell a story of warm >>>> spring and summer temperatzures, but this is the only >>>> proxy-information >>>> which really favours the warm solution without corrections. Not to >>>> forget at >>>> last the "official" Central European CRU-version published in box >>>> 3.6, Fig.2 >>>> of WG1-2007 report which shows rather high EI-summer temperatures, >>>> just as >>>> our own HISTALP series did before the EI correction. >>>> >>>> SO if you ask me I am convinced that our new version of longterm >>>> temperature >>>> records is nearer to the truth than the other existing ones without >>>> EI-corrections. But I am not sure, whether we should extrapolate >>>> too much to >>>> other regions. Series like Berlin or perhaps Paris should be the >>>> outermost >>>> locations for it, Southern Sweden may need stronger corrections (as >>>> you have >>>> already shown Anders), oceanic locations in UK maybe weaker ones >>>> and about >>>> the south I am not sure which factor really dominates, the described >>>> astronomical or the climatological influences. So I guess for the >>>> time being >>>> we have a good solution for Central Europe, but we will have >>>> difficulties to >>>> find quantitative information for other regions as long as the >>>> "Kremsmünsters" of the North, the West, the South and the East are >>>> not yet >>>> existing. How about starting such comparative monitoring? Some of the >>>> original EI-buildings should still exist. >>>> >>>> OK, that’s all for the moment, I hope it provided the >>>> Millennium-group with >>>> some useful facts for the decisions Anders was writing about. >>>> >>>> Best regards >>>> >>>> Reinhard >>>> >>>> P.S.: I cc. this also to Phil, maybe ha also has some comments >>>> >>>> -----Ursprüngliche Nachricht----- >>>> Von: Anders Moberg [mailto:anders.moberg@natgeo.su.se] Gesendet: >>>> Montag, 16. Juni 2008 23:34 >>>> An: Reinhard Boehm >>>> Cc: 'Brazdil Rudolf'; Petr Dobrovolny >>>> Betreff: Re: AW: Central European temperature reconstruction >>>> >>>> Dear Reinhard, >>>> >>>> cc. Rudolf and Petr >>>> >>>> Thanks indeed for sending this information and corrected data. They >>>> come very timely! I need not to say (as you already know it) that I >>>> consider it to be very important that you have developed these >>>> corrected series. >>>> >>>> I do understand that you will describe how you did the >>>> EI-corrections in the paper. But can you tell us in a few sentences >>>> what it is based on? By looking at your presentation (the >>>> pdf-file), I assume that your 8-yr parallell observations in >>>> Kremsmuenster forms the basis for your correction. Is this right? >>>> But how do you apply this knowledge to the other stations? Does >>>> your correction model account for the orientation (e.g. NE, NW, >>>> etc) of the thermometer-wall at each site? Do you account for >>>> observation hours? Latitude? It would be good to get just some >>>> hints of what you did. >>>> >>>> I also have some comments that I would like address to Rudolf and >>>> Petr: Given that this paper by Reinhard et al (as far as I >>>> understand) will be the paper about long instrumental records in >>>> the CC special issue, it is important that other related papers use >>>> the new homogenised series for the sake of consistency. In >>>> particular, the paper about Central European temperatures should be >>>> as consistent as possible with the new EI-corrected data. We agreed >>>> some week ago to use a combination of >>>> [Kremsmuenster+Basel+Prague+Rapp's German average] to construct the >>>> instrumental regional average. As Reinhard now has developed >>>> homogenised versions of both Kremsmuenster and Basel, we should use >>>> these new versions. I assume that you can also use the new >>>> EI-corrected series in your homogenisation of Prague. As concerns >>>> the Rapp series for Germany, the situtation is more tricky. We >>>> could in principle consider using an average of (some of) the >>>> German stations in Reinhard's dataset (Hohenpeissenberg, Karlsruhe, >>>> Munchen, Regensburg, Stuttgart). But then we would miss information >>>> from more northern parts of Germany. I actually think it is more >>>> important to have the EI-corrected German series from southen parts >>>> of Germany than having un-corrected Rapp data for all Germany. We >>>> might consider some compromise? E.g. homogenising the Rapp series >>>> with the EI-corrected German series as reference series. Another >>>> thing; we could also consider using more station records from >>>> Switzerland and Austria than only Basel and Kremsmuenster. I think >>>> we should have a little email conversation about this, so that all >>>> of us can say our opinions before we decide on how to construct an >>>> appropriate Central European temperature series to be used for >>>> calibration of the documentary data from CZ+DE+CH. What is your >>>> opinion -I mean all three of you? >>>> >>>> Regards, >>>> Anders >>>> >>>> >>>> Reinhard Boehm skrev: >>>> >>>> >>>>> Dear Anders, dear Rudolf >>>>> >>>>> Please understand my delay in answering your questions and your data >>>>> request. The reason war quite a complicated decision finding process >>>>> >>>> >>>> mainly >>>> >>>> >>>>> with the Italian co-authors about our definite result in >>>>> correcting the >>>>> EI-bias in early warm-season temperatures. >>>>> But last week we came to the decision about our definite new >>>>> version of 32 >>>>> Central European temperature series starting before 1850. And I, >>>>> as the lead-author finally decided to write the paper as part of >>>>> >>>> >>>> your >>>> >>>> >>>>> planned Millennium-publication, Rudolf asked me to contribute to >>>>> some time >>>>> ago. >>>>> So I have finally started writing and for Your information I >>>>> attach the >>>>> recent (yesterday's) status of the paper plus a presentation I >>>>> gave about >>>>> >>>> >>>> it >>>> >>>> >>>>> (see at pages 7 to 12 of the attached Mondsee-pdf). >>>>> I also attach 2 xls-files. The first contains all 32 EI-series in the >>>>> >>>> >>>> region >>>> >>>> >>>>> in three different modes: (from left to right) EI-corrected, >>>>> homogenised >>>>> >>>> >>>> but >>>> >>>> >>>>> not EI-corrected and the original series (only outlier corrected) >>>>> The second xls-file explains the station code and it also tells >>>>> you whom >>>>> >>>> >>>> you >>>> >>>> >>>>> should acknowledge as data provider, if you explicitly use one of >>>>> these >>>>> series in the publication. >>>>> Best regards >>>>> >>>>> Reinhard >>>>> -----Ursprüngliche Nachricht----- >>>>> Von: Anders Moberg [mailto:anders.moberg@natgeo.su.se] Gesendet: >>>>> Mittwoch, 28. Mai 2008 11:38 >>>>> An: reinhard.boehm@zamg.ac.at; Dr. Ingeborg Auer >>>>> Cc: Brazdil Rudolf; Petr Dobrovolny; Rob Wilson >>>>> Betreff: Central European temperature reconstruction >>>>> >>>>> Dear Reinhard and Ingeborg, >>>>> >>>>> cc. Rudolf, Petr, Rob, >>>>> >>>>> Hope all is well with you! As you probably already know, I am >>>>> working together with Rudolf, Petr, Rob and other colleagues in >>>>> Millennium with writing papers for the Special Issue in Climatic >>>>> Change that Rudolf is organizing. I have understood that Reinhard >>>>> is contributing with a chapter about long instrumental records. >>>>> >>>>> One of the chapters will deal with reconstruction of monthly >>>>> temperatures for Central Europe back to 1500, based on index >>>>> series derived from documentary evidence from Germany, Switzerland >>>>> and the Czech Republic. In the last few weeks, I have been engaged >>>>> in the problem of calibrating these data against long instrumental >>>>> data for Central Europe, and to put error bars on them. The basic >>>>> principle for the calibration is simple linear regression for a >>>>> period of overlapping data. The attached figure shows you some >>>>> preliminary results for seasonal averages (month 13 = DJF, 14=MAM, >>>>> 15=JJA, 16=SON). The error bars are 2*sigma error from >>>>> calibration, with additional adjustment for changes in running >>>>> correlations between the individual country series. (The error bar >>>>> estimation for these data is far from trivial, but this is not >>>>> what this email is about ...) >>>>> >>>>> So far, the instrumental data I used are taken from the CRUTEM2v >>>>> dataset, with an extension back to 1781. Phil Jones and I created >>>>> a long record for Central Europe (CE) from these data, for a paper >>>>> we published in 2003. I use the same series here. However, we are >>>>> discussing if we should rather use another average temperature >>>>> series for CE which we develop specifially for this paper. This is >>>>> the real reason for writing to you: We would need the best >>>>> available long instrumental records from Germany, Switzerland and >>>>> the Czech Republic to construct a suitable CE series. Would you be >>>>> interested in contributing with a selection of series from >>>>> HISTALP? Data from Austria can also be considered, even if no >>>>> documentary data from your country are used, because Austria fits >>>>> well into the climatic region of interest. >>>>> >>>>> We are of course aware of the problem of possible too warm summer >>>>> temperatures before mid-19th century. As you can see in the >>>>> attached plot, the reconstructed (smoothed) JJA temperatures lie >>>>> consistently above the zero line (1961-90 average). Obviously, if >>>>> the instrumental temperatures are biased in the calibration period >>>>> (1781-1820), then the entire reconstruction will also be biased. >>>>> >>>>> If you have any instrumental series in the pipeline that are >>>>> corrected for this bias, then it would be excellent if we could >>>>> use them. Maybe you are planning to present such series in your >>>>> chapter of the Special Issue?? If so, it would be a very nice >>>>> connection between the two papers, if we can use the same data. >>>>> >>>>> If you don't have any such corrected data, then we can at least >>>>> point out the problem and discuss it properly. In any case, we >>>>> feel that it would be good to build a new instrumental CE >>>>> temperature series, to be used here rather than the extended >>>>> CRUTEM series. Many early data records in the CRUTEM dataset have >>>>> not been subject to homogeneity testing. Rather, the dataset is >>>>> just a collection of what Phil has been able to collect. (For >>>>> example, it contains Austrian series from ALOCLIM and data from >>>>> IMPROVE, but there are also other more or less untested early data). >>>>> >>>>> We hope that you would like to collaborate by contributing with >>>>> your most appropriately selected station records. If you would >>>>> like to do this, then we would need the data very soon as we are >>>>> approaching the deadline for the paper and other chapters in the >>>>> special issue are dependent on using our reconstruction. So, >>>>> please, answer as soon as you can and tell us if, and how, you can >>>>> contribute. I am convinced that Petr (who is the lead author) is >>>>> happy to include you as co-author(s) if you like. >>>>> >>>>> Looking forward to hear from you soon, >>>>> >>>>> Best regards, >>>>> Anders >>>>> >>>>> >>>> >>>> >>>> >>> >>> >> >