Intellectual achievements
of Hans von Storch

Foto vom Storch

The term "downscaling" and the first examples of using the statistical variant of this approach for the construction of climate change scenarios.

The term "downscaling" was first used in the MPI Report #64 - Hans von Storch, Eduardo Zorita, Ulrich Cubasch (1991): Downscaling of Global Climate Change Estimates to Regional Scales: An Application to Iberian Rainfall in Wintertime. This approach was developped out of a request for elaborating the utility of GCM output, asked by a group of German hydrologists - the details of the meeting are by now forgotten. In this paper, Hans von Storch and Eduardo Zorita applied Canonical Correlation Analysis to derive Iberian Peninsula seasonal rainfall change in winter from global GCM scenarios

The work was inspired by Kim, J.W., J.-T. Chang, N.L. Baker, D.S. Wilks and W.L. Gates, 1984: The statistical problem of climate inversion: Determination of the relationship between local and large-scale climate. Mon. Wea. Rev. 112: 2069-2077, .

A first sketch was presented in
von Storch, H. and E. Zorita, 1990: Assessment of regional climate changes with the help of global GCM's: an example. CAS/JSC Working group on Numerical Experimentation. WMO Report no. 14, 7.30

Eventually the method and the analysis were finally published first in Spain and then in the Journal of Climate:
Zorita, E. and H.von Storch, 1991: Estimacion de cambios en la precipitacion en la Peninsula Iberica a partir de experimentos con modelos de circulacion general. In "Modelos en Meteorologia y Climatologia", Universidad Complutense, Madrid
von Storch, H., E. Zorita and U. Cubasch, 1993: Downscaling of global climate change estimates to regional scales: An application to Iberian rainfall in wintertime. - J. Climate 6: 1161-1171 - the MPI report #64 mentioned above was the preprint of this article.

In 2019, Hans von Storch and Eduardo Zorita published a kind of review of the foundations of empirical downscaling, and its roots in synoptic climatology and spatial interpolation:
von Storch, H., and E. Zorita, 2019: The history of ideas of empirical downscaling – from synoptic dynamics and spatial interpolation. Frontier (doi: 10.3389/fenvs.2019.00021; 8 pp.)

The spectral nudging technique used in dynamical downscaling for, mainly, reconstructing regional climate extending decades of years but also for scenario construction.

The problem of simulating the regional climate conditional upon the large scale state of a re-analysis or a GCM simulation is no longer formulated as a boundary-value problem but as a data-driven problem, with the known large-scale conditioning the medium- and small scale dynamics. In doing so, it becomes also clear that the expected value added is not in the large scales, which are already described by the global model/analysis but in those scales, which are insufficiently resolved by the global analysis/model.
von Storch, H., H. Langenberg and F. Feser, 2000: A spectral nudging technique for dynamical downscaling purposes. Mon. Wea. Rev. 128: 3664-3673.

Preliminary "grey" versions were
Langenberg, H, and H. von Storch, 1999: Spectral analysis in regionalisation retaining the large scales but adding detail. In H. Ritchie (Ed.): Research Activities in Atmospheric and Oceanic Modelling, WMO/TD No 942, 7.31-32
and von Storch, H., H. Langenberg and F. Feser, 1999: Long-wave forcing for regional atmospheric modelling. GKSS 99/E/46 report

That the scheme actually is superior than in the conventional formulation in generating mesoscale variability in a correctly described large scale dynamical environment has been demonstrated by a series of authors, in particular Frauke Feser, 2006: Enhanced detectability of added value in limited area model results separated into different spatial scales. Mon. Wea. Rev. 134(8), 2180-2190. Aso an improved description of the formation of North Atlantic Polar Lows (Zahn, M., H. von Storch, and S. Bakan, 2008: Climate mode simulation of North Atlantic Polar Lows in a limited area model, Tellus A, DOI: 10.1111/j.1600-0870.2008.00330.x) and E Asian typhoons (Feser, F., and H. von Storch, 2008: A dynamical downscaling case study for typhoons in SE Asia using a regional climate model. Mon. Wea. Rev. 136, 1806-1815) as well as other mesoscale storms has been shown - as compared to only laterally constrained simulations.

In 2011, the different lines of analysis of the added value generated in this way was described in a review paper Regional climate models add value. in Bull. Amer. Meteor. Soc. (92: 1181–1192) coauthored by F. Feser, B. Rockel, H. von Storch, J. Winterfeldt, and M. Zahn. After having been implemented in limited area software like WRF, the spectral nudging method finds more an more acceptance and is often utilized.

The same terminology and a similar approach had been earlier published by Waldron, K. M., J. Peagle and J.D. Horel, 1996: Sensitivity of a spectrally filtered and nudged limited area model to outer model options. Mon. Wea. Rev. 124, 529-547. At the time of submitting our manuscript, this paper was unknown to Hans von Storch, as it dealt with issues of weather forecasting, and he learned from it during the review process. Earlier a number of authors (Kida, Sasaki, McGregor) had experimented with nudging spatial means.

Need for signal-to-noise analysis for assessing the outcome of numerical experiments with atmospheric limited area models just as with global model experiments.

It was accepted in the early 1970s that ensembles of global model (GCM) simulations, which differ by miniscule details, such as modified initial values or parameters, would show strong variability reflecting internal chaotic dynamics. This observation was important for both validating models, as simple comparisons of observations and a model simulation would not be conclusive becaused the differences may very well be due to ensemble variations, and for doing numerical experiments on the effect of changing parametrizations or boundary conditions (such as sea surface temperature). As a consequence, the concept of using the concept of testing null hypotheses was introduced and became quickly a stand routine in validating of and experimenting with GCMs.

Not so with regional climate models (RCMs). While the situation is in principle the same - the lateral boundary conditions, which are usually stipulated via "sponge zone, are insufficient to enforce a unique solution in the intgerior, and the chaotic dynamics generate - at least sometimes - different circulations in the interior, which are consistent with the lateral boundary conditions. Thus, validation of and experimenting with RCMs needs the same statsitical analysis as for global models. Ioneers in demonstrating the emrgence of ensm,eble variations in RCMs simulations were Ji and Vernekar in 1997 (J. Clim 10), and Annette Rinke and Klaus Dethloff in 2000 (Clim. Res. 14). But even nowadays, in 2012, the statistical challenge of assessing RCM output has not been acknowledged by many in the RCM community.

However, there is a characteristic difference in the ensemble structure between different trajectories generated by global and regional models. Once two global models trajectories have moved from each other, they will remain at a statistically stationary distance. In case of RCMs, this is different, because the efficiency of lateral boundary conditions vary in enforcing a circulation in the interior. Sometimes they do it really well, and any two trajectories move closer, while in other situations the differences grow, sometimes strongly within a short term and only for a limited time.

The principle was described in this article: Weisse, R., H. Heyen and H. von Storch, 2000: Sensitivity of a regional atmospheric model to a sea state dependent roughness and the need of ensemble calculations. Mon. Wea. Rev. 128: 3631-3642, which unfortunately received little attention so far.

At a later time, I coined the term "intermitted divergence in phases space" for this phenomenon. (von Storch., H., 2005: Models of global and regional climate. M.G. Anderson (Ed): Encyclopedia of Hydrological Sciences, Part 3. Meteorology and Climatology, Chapter 32, ISBN: 0 471-49103-9, p 478-490 DOI: 10.1002/0470848944.hsa035) This intermitted divergence in phase space is strongly suppressed, when spectral nudging is employed (see Weisse and Feser, 2003, Coastal Eng. 48.)

N European storms - WASA

  1. WASA, 1998: Changing waves and storms in the Northeast Atlantic? - Bull. Amer. Met. Soc. 79, 741-760
  2. Zahn, M., and H. von Storch, 2008: A longterm climatology of North Atlantic Polar Lows. Geophys. Res. Lett., 35, L22702, doi:10.1029/2008GL035769
  3. Zahn, M., and H. von Storch, 2010: Decreased frequency of North Atlantic polar lows associated to future climate warming, nature 467, 309-312


Originally introduced by Klaus Hasselmann in a rather general concept, later expanded to Principal Interaction Patterns (PIPs, see Hasselmann, 1988, I derived a simplified but workable version, which nowadays goes with the name of Principal Oscillation Patterns (POPs; see von Storch et al., 1988. The basic idea is to identify a low-dimensional linear subspace, which is dynamically closed (interacting with other dynamcis only through links, which are suitably described by statistical terms). The PIPs represent a very general, and elegant, approach, while the POPs reduced this to the case of 2-dimensional subspace, within which oscillatory modes descrrbe most of the variation. Both, PIPs and POPs incorporate a predictive potential.

PIPs have never been implemented in its full generality; POPs have been successfully applied to the Madden & Julian Oscillation and to ENSO, among other phenomena. A review dates from 1995. The original FORTRAN code from about 1991 has been preserved (thanks to Silvio Gualdi),to gether with the manual (by Fergus Gallagher, Reiner Schnur, Gerhard Hannoschöck and myself) from those days.

Hasselmann, K., 1988: PIPs and POPs: The reduction of complex dynamical systems using Principal Interaction and Oscillation Patterns. J. Geophys. Res. 93, 11015-11021
von Storch, H. T. Bruns, I. Fischer-Bruns and K. Hasselmann, 1988: Principal Oscillation Pattern analysis of the 30-60 day oscillation in a GCM equatorial troposphere. - J. Geoph.Res. 93, 11022-11036
von Storch, H., G. Bürger, R. Schnur, and J. von Storch, 1995: Principal Oscillation Pattern: A review. - J. Climate 8, 377-400

The deconstruction of the "hockeystick" methodology

The "hockeystick"-episode was a tough time, also interesting in terms of the social process called science. We have summarized how we perceived this time in a comment on the weblog of nature. The problem was that the scienbtist behind the hockeystick used the unfortunate declaration that the hockeystick would be "it", by the IPCC (TAR) as a tool to block others who would come forward with different results; in particular borehole temperature people suffered.

For the debate about detecting and attributing man-made climate change the hockeystick was unnecessary, as was demonstrated by our later analysis (Rybksi et al.) in 2006, which employed various reconstructions; also formal detection and attribution studies had solved the problem long before (e.g., IDAG, 2005: Detecting and attributing external influences on the climate system. A review of recent advances. J. Climate 18, 1291-1314; or, much earlier Hegerl, G., H. von Storch, K. Hasselmann, B.D. Santer, U. Cubasch, P.D. Jones, 1996: Detecting anthropogenic climate change with an optimal fingerprint method. - J. Climate 9, 2281-2306)

The "skeptics" were keen on deconstructing the hockeystick because they considered it as a key argument "pro" man-made causes. However, it was not, and the fact that the hockeystick methodology was flawed did not imply that the question about man-made causes would be entirely open again. (Of course there is some doubt left, because of significant uncertainty in the level of natural variability - but this doubt is small.) This demonstrates very clearly that overselling does not pay; instead it endangers the credibility of the whole community.

The significance of hockeystick business is illustated by the fact that it brought me an invitation to show up as a witness first at the National Research Council and later at the Subcommittee on Oversight and Investigations of the Committee on Energy and Commerce, U.S. House of Representatives. (Hearing "Questions Surrounding the ‘Hockey Stick’ Temperature Studies: Implications for Climate Change Assessments" on 19. July 2006)

The key-paper of this effort was
von Storch, H., E. Zorita, J. Jones, Y. Dimitriev, F. González-Rouco, and S. Tett, 2004: Reconstructing past climate from noisy data, Science 306, 679-682, 22 October 2004 (Sciencexpress, doi 10.1126/science.1096109)
which was commented to by Osborn and Briffa, and by S. Rahmstorf.

A kind of final word from our side is provided by
von Storch, H., E. Zorita and J.F. González-Rouco, 2009: Assessment of three temperature reconstruction methods in the virtual reality of a climate simulation. International Journal of Earth Sciences (Geol. Rundsch.) 98:67–82 DOI 10.1007/s00531-008-0349-5 .

Science - public/media/politics interaction; post-normal science

mostly with Nico Stehr as well as the sociologist Dennis Bray

  1. von Storch, H. and N. Stehr, 1993: Genarrt vom Wettergott. ZEIT 37, 10.9.93, 41-42
  2. Stehr, N. and H. von Storch, 1994: Climate change, the social construct of climate and climate policy. Proc. of the Fifth Symposium on Global Change Studies, Nashville, Tennessee, January 23-28, 1994, 118-125.
  3. Stehr, N. and H. von Storch, 1995: The social construct of climate and climate change. - Clim. Res. 5, 99-105
  4. Stehr, N., H. von Storch and M. Flügel, 1996: The 19th century discussion of climate variability and climate change: analogies for present day debate? World Res. Rev. 7, 589-604
  5. von Storch, H., and N. Stehr, 1997: The case for the social sciences in climate research. - Ambio 26, 66-71 (also in: H. Rodhe and R. Charlson (Eds), 1998: The legacy of Svante Arrhenius. Understanding the greenhouse effect. Royal Swedish Academy of Sciences, Stockholm, ISBN 91-7190-0284, 143-153)
  6. Stehr, N. and H. von Storch, 1997: Das soziale Konstrukt des Klimas. In: VDI-Gesellschaft Energietechnik (Ed): Umwelt- und Klimabeeinflussung durch den Menschen IV, VDI Berichte 1330, 187-197 (ISBN 3-18-0913304)
  7. Stehr, N. and H. von Storch, 1997: Rückkehr des Klimadeterminismus? Merkur 51, 560-562
  8. Stehr, N., und H. von Storch, 1998: Soziale Naturwissenschaft oder die Zukunft der Wissenschaftskulturen. Vorgänge 37, 8-12
  9. Stehr, N., and H. von Storch, 1999: An anatomy of climate determinism. In: H. Kaupen-Haas (Ed.): Wissenschaftlicher Rassismus - Analysen einer Kontinuität in den Human- und Naturwissenschaften. Campus-Verlag Frankfurt.a.M. - New York (1999), 137-185, ISBN 3-593-36228-7
  10. Stehr, N. and H. von Storch, 2000: Klima und Kultur. Vorgänge 39, 100-104
  11. Stehr, N. and H. von Storch, 2000: Von der Macht des Klimas. Ist der Klimadeterminismus nur noch Ideengeschichte oder relevanter Faktor gegenwärtiger Klimapolitik? Gaia 9, 187-195
  12. Stehr, N., and H. von Storch, 2000: Weine nicht, wenn der Regen fällt, WELT 4.10.2000
  13. von Storch, H. und N. Stehr, 2001: Was weiss denn schon der Wetterfrosch? WELT, 23.3.2001, S. 35
  14. Stehr, N., and H. von Storch, 2002: Klimawandel und Gesellschaft. Grenzen der Erkenntnis. Kultur & Technik 03/2002, 39-41
  15. von Storch, H. and N. Stehr 2002: Das Klima in den Köpfen der Menschen. In: Walter Hauser (Ed.): Klima. Das Experiment mit dem Planeten Erde Deutsches Museum. Begleitband und Katalog zur Sonderausstellung des Deutschen Museums vom 7.11.02-15.06.2003, 280-291 (also Velbrueck on-line Magazin 2/2002)
  16. Stehr, N. and H. von Storch, 2002: Die Meinungssache namens Wetter, Frankfurter Allgemeine Zeitung, 14.8.2002, (nr 187), p. 38
  17. von Storch, H., and N. Stehr, 2003: Effiziente Kommunikation, resistente Gesellschaft?, Universitas 6/2003, Nr. 684, 608-614
  18. von Storch, H., und N. Stehr, 2005: Klima inszenierter Angst. SPIEGEL 4/2005, 160-161
    A Climate of Staged Angst,
    Et klima af iscenesat frygt. Vejret 10, 39-42
    Geënsceneerede klimaatangst. Natuur, Wetenschap & Techniek 73, 44-46
  19. Stehr, N. und H. von Storch,2007: Die alltägliche Hybris. Gazette 16, 31-33 (leicht gekürzt gegenüber dem Originalmanuskript Von der Erforschung und der Politik des Machbaren)
  20. von Storch, H., und N. Stehr, 2007: Der öffentliche Diskurs über das Klima oder – die politische Macht der Klimaforschung. In Philipp Mißfelder (Hrsg.): Umdenken. Für eine nachhaltige Klimapolitik, 14-21
  21. von Storch, H.,2007: Postnormale Wissenschaft. Weltwoche 23/2007, p. 131
  22. von Storch, H., und N. Stehr, 2007: Essay: Nur keine unbequeme Wahrheit. ZEIT Wissen, 18.10.2007
  23. von Storch, H., und N. Stehr, 2007: Anpassung an den Klimawandel. Aus Politik und Zeitgeschichte 47/2007, 19.11.2007 (English translation)
  24. Stehr, N., und H. von Storch, 2008: 10-Punkte Manifest: So kann Deutschland den Klimawandel bewältigen - spiegel online,,1518,576032-11,00.html (This is the so-called "Zeppelin Manifesto")
  25. von Storch, H., 2009: Klimaforschung und Politikberatung - zwischen Bringeschuld und Postnormalität. Leviathan, Berliner Zeitschrift für Sozialwissenschaften 2009, 37:305–317, DOI 10.1007/s11578-009-0015-8 (open access)
  26. von Storch, H., 2009: Climate Research and Policy Advice: Scientific and Cultural Constructions of Knowledge. Env. Science Pol. 12, 741-747
  27. Stehr, N., und H. von Storch, 2009: Die lästige Demokratie. Spiegel on-line, 29.Dezember 2009
  28. Stehr, N., und H. von Storch, 2009: Klimaschutz und Vorsorge, forum 291, 21-24
  29. Stehr, N., and H. von Storch, 2009: Climate Protection. J. Verbr. Lebensm. 1661-5751/00/000001-5, DOI 10.1007/s00003-008-0392-z
  30. von Storch, H., und N. Stehr, 2010: Thoughts on climate research and policy. Newsletter of Europäischen Akademie Bad Neuenahr-Ahrweiler GmbH 99, S. 1-2; also published online on Climate Science and Policy
  31. von Storch, H., und N. Stehr, 2010: Klimaforschung und Klimapolitik – Rollenverteilung und Nachhaltigkeit . Naturwissenschaftliche Rundschau 63, nr. 744, 301-307
  32. von Storch, H., 2010: Protagonists on the Market of Climate Change Knowledge. In Max Boykoff (ed.): Politics of Climate Change. Rutledge, London New York, ISBN 978-1-85743-496-5, 303 pp, 62-76
  33. von Storch, H., 2010: Klimaforschung - zwischen akademischer Neugier und kultureller Konditionierung. In Philipp Wolf und Dietmar Herdt (Hrsg.): Global Warming. Ethische und technologische Perspektiven des Klimawandels, Leipziger Universitätsverlag GmbH 2009, ISBN 978-3-86583-427-0, 47-58 (Buchbesprechungen: Umweltdialog, )
  34. von Storch, H., and D. Bray, 2010: Against politicization of science. Comment on S. Keller: Scientization: Putting global climate change on the scientific agenda since 1970 and the role of the IPCC, Poiesis&Praxis, 7:211–219, DOI 10.1007/s10202-010-0085-3, open access.
  35. von Storch, H., A. Bunde and N. Stehr, 2011: The Physical Sciences and Climate Politics In J.S. Dyzek, D. Schlosberg, and R. B. Norgaard (eds): The Oxford Handbook of Climate Change and Society. Oxford University Press. Oxford UK. (in press)

The ongoing trans-disciplinary cooperation between the theoretical sociologist Nico Stehr and the climate scientist Hans von Storch has also resulted in a joint book, a first issue published in German in 1999 (and later in Chinese), and a second in 2010 in English, German, Slowenian, Russian, and Tchechian:

Assessment reports such as BACC und Hamburg-report

So far such reports on the scientifically legitimate knowledge about climate, climate change and climate impact have been published:

  1. von Storch, H., M. Claussen and KlimaCampus Autoren Team, 2010: Klimabericht für die Metropolregion Hamburg, Springer Verlag Heidelberg Dordrecht London New York, DOI 10.1007/978-3-642-16035-6, 321 pp

  2. The BACC author team, 2008: Assessment of Climate Change in the Baltic Sea Basin., Springer Verlag Berlin - Heidelberg; ISBN 978-3-540-72785, 473 pp

  3. The BACC-II author team, 2015: Second Assessment of Climate Change for the Baltic Sea Basin. Springer Verlag, 506pp, ISBN 978-3-319-16005-4, open access

The Hamburg community is presently preparing an updated, due in 2017, under the auspices of the Hamburg KlimaCampus. A similar effort is presently underway for the North Sea region, see NOSCCA.

A short version of BACC-I is given by
Reckermann, M., H.-J. Isemer and H. von Storch, 2008: Climate Change Assessment for the Baltic Sea Basin. EOS Trans. Amer. Geophys. U., 161-162

An analysis of the recognition of the BACC report among regional stakeholders is provided by
Bray, D., 2010: Baltic Climate Scientists’ Assessment of Climate Change and Climate Science in the Baltic Sea Basin, International BALTEX Secretariat Publication 48, ISSN 1681-6471, 79 pp.

Regional Climate Service

  1. von Storch, H. and I. Meinke, 2008: Regional climate offices and regional assessment reports needed. Nature geosciences 1 (2), 78, doi:10.1038/ngeo111
  2. von Storch, H., I. Meinke, N. Stehr, B. Ratter, W. Krauss, R.A. Pielke jr., R. Grundmann, M. Reckermann and R. Weisse, 2011: Regional Climate Services illustrated with experiences from Northern Europe. Zeitschrift für Umweltpolitik & Umweltrecht 1/2011, 1-15

Bilder der Küste

Döring, M., W. Settekorn and H. von Storch (Eds.), 2005: Küstenbilder, Bilder der Küste. Hamburg University Press 362 pp, ISBN 3-9808223-1-1

  1. Settekorn, W., M. Döring und H. von Storch, 2000: Ergebnisbericht des Kooperationsprojekts Bilder der PALLAS, GKSS Report 2000/43, 18pp.
  2. Döring, M., W. Settekorn and H. von Storch, 1999: Grenzen und Chancen der Wissenschaftskommunikation. Die Havarie der "Pallas" als Symbol. Vorgänge 148, 4: 13-16

(Graphik zusammengestellt von Ina Frings, HZG)