A.Valery, V.Andreassian & C. Perrin

Tison Award 2010 / Prix Tison 2010

Presentation of the Tison Award 2010 on July 2, 2010, at UNESCO headquarters in the framework of the 10th Kovacs Colloquium

From left to rigth : Gordon Young, Charles Perrin, Audrey Valéry, Vazken Andréassian et Zbigniew Kundzewicz
UNESCO, Paris, 2 July 2010

Citation - Tison Award 2010

The Jury of the 2010 Tison Award recommended bestowing the 2010 Tison Award upon three young French hydrologists: Audrey VALERY, Vazken ANDREASSIAN & Charles PERRIN from Cemagref, Hydrosystems and Bioprocesses Research Unit, based in Antony, France. The winning paper: Inverting the hydrological cycle: when streamflow measurements help assess altitudinal precipitation gradients in mountain areas was published in the IAHS Publication No. 333 in 2009. All three authors meet the age requirement of the Tison Award (under 41 in the moment of publication of the awarded paper) and share the Award.

The awarded paper implements a challenging idea of solving an inverse problem in hydrology, i.e. reconstructing the input signal from analysis of the output signal. The authors attempt to "invert" the hydrological cycle and to draw corollaries on precipitation in data-sparse mountainous regions by using streamflow observations. The inverse problem, known in applied mathematics and theoretical hydrology, is regarded as very difficult (ill-posed) in general, yet the authors deal with an even more difficult special case of determining precipitation in mountainous areas, where the observations are sparse and of inadequate quality. The authors attempt to offer an informed guess on the quantity of precipitation falling at higher elevations where no observations are made. The authors used data sets from Swiss and Swedish catchments, and three simple long-term water balance formulas (proposed by Budyko, Ol'dekop and Turc-Le Moine). By assuming a simple two-parameter correcting model to regionalize precipitation from a sparse precipitation gauging network, the authors show that it is possible to identify the precipitation-elevation relationship from streamflow, while the snow undercatch parameter remains more difficult to identify.

I am very glad to inform you that the awarded paper is just an entrée for a new, substantial contribution by the authors. They contributed to a forthcoming special issue [55(6)] of Hydrological Sciences Journal. There is another interesting paper in this special issue, jointly authored by all three Tison 2010 laureates. Moreover, Dr Andréassian and Dr Perrin have, in fact, done considerable work, standing behind this whole, very interesting, special issue entitled "Court of miracles of hydrology". The principal message conveyed by this special issue is that a thoughtful analysis of failure stories can indeed contribute to the advancement of hydrological sciences.

Finally, let me end with a personal reflection. Twenty-three years ago, in 1987, in Vancouver (British Columbia, Canada), the Tison Award distinguishing a best paper in IAHS publications of a young author, was given for the first time. I am proud to say that I was the first laureate. This Prize, whose monetary value is only symbolic, has had a considerable impact on my scientific career.

Ladies and Gentlemen, I feel honoured and pleased to bestow the 2010 Tison Award to Audrey VALERY, Vazken ANDREASSIAN & Charles PERRIN. Let me wish that this Prize marks an important milestone in their scientific careers.

Z. W. Kundzewicz
IAHS Editor and Chair of the Jury of the 2010 Tison Award

Answer to Prof. Kundzewicz's Citation – Tison Award 2010, pronounced by Vazken Andréassian

Dear Prof. Kundzewicz,

Receiving the Tison Award from your hands is indeed a great honor for us three. We are extremely proud to see our names added to the list of great hydrologists who previously received this award. We must confess that when IAHS Secretary General Pierre Hubert called us to announce it, it was a real surprise. Even if French are not best known worldwide for being modest, the question that immediately came to us was: "do we really deserve it?".

Do we really deserve it? This is a difficult question. We can think of many talented young colleagues that in our eyes would equally deserve it. If regretted former IAHS President Vit Klemeš was still with us, he would have found an answer... he would probably have asked radio Yerevan about it, like he did once in his 1988 paper entitled "A hydrological perspective". This would probably have yielded something like:

Question to radio Yerevan:
Do these three French scientists deserve the Tison award for the young deserving hydrologists ? And the answer would probably have been:
In principle yes,
they are not deserving, they are lumped modelers and their models are full of "fudge factors",
and they are not young, two of them already have some grey hairs (that they did not even try to die for this ceremony),
and it is doubtful that they are actual hydrologists, since they hardly drink any water.

Now that this essential question has been solved, and that most of the time we had been allocated for answering has been spent, please allow us to go straight to the important things. An award-giving ceremony is the occasion to thank all those who have helped us on our way, because like Isaac Newton said, "If we have seen further, it is only by standing on the shoulders of giants".

  • The first of these giants is somebody few of you have heard of, and that very few of you have ever seen. His name is Claude Michel, a retired hydrologist of Cemagref. Perhaps Prof Kundzewicz still remembers him as a regular reviewer of papers for the IAHS journal. His humility was sometimes excessive, fed by many years of hydrological practice, but it was extremely instructive for us. He taught us Hydrology, we owe him our concern for parsimony, and the requirement that any new model change should be tested on a few hundreds of catchments before being seriously considered. He was deeply respectful of younger people: he was always trying to convince us that the solution he had proposed was in fact our own idea.
  • Working with such a man leaves its marks on young people, and most of the PhD students who have worked with him and later with us were irremediably marked by this experience. We definitely keep extremely strong links with each other. We even arrange to spend week-ends together, notably to celebrate the so-called NASH ("Nouvelle Année Socialement Hydrologique") under the responsibility of an "international social hydrology club". To mention but a few, we want to cite in particular Thibault Mathevet, Ludovic Oudin, Marie Bourqui, Nicolas le Moine, Julien Lerat, Lionel Berthet, Jean-Luc Payan outside Cemagref, and Cécile Loumagne, Helena Ramos, Marine Riffard, Mamoutou Tangara in our research group. This award belongs collectively to all of them.
  • We also wish to thank all our colleagues from other institutes in France and in many parts of the world, for collaborations over the past years, for lively debates and passionate discussions about hydrological science… which we sometimes continued on frisbee fields!
  • Then we would like to cite the names of colleagues which honor us today by their presence: Prof. Ghislain de Marsily of the French Academy of Sciences, Jean Margat, Dr Claude Cosandey, Roger Genet (Director General of Cemagref), Pierrick Givone (Director for Strategy of Cemagref) and Etienne Frossard (Technical Director of Coyne et Bellier).
  • Our thoughts go also to our families (spouses, partners, children and parents…) to thank them for their unfailing support on our hydrological pathways.
  • Last but not least, we would like to thank the Tison Award committee, Secretary General Pierre Hubert and President Gordon Young, Profs Kundzewicz and Koutsoyiannis, as well as Cate Gardner and Frances Watkins.

We would like to dedicate our last words to Prof. Léon Tison, after which this award has been named. We are definitely too young to have known Prof. Tison, but we talked a couple of days ago with our retired colleague Jean Margat who knew Prof. Tison personally. He had first met Prof. Tison fifty years ago, when receiving financial support from IAHS to travel to a conference in Athens. He remembers him as a distinguished person, who extracted from his pocket a load of green dollars to give him the financial support awarded by IAHS. For young hydrologists wishing to travel to international conferences and to build their own research group, let us recognize that green is, after blue, the second favorite color.