D. Hannah & D. Lavers

Citation for the 2014 Tison Award

by Demetris Koutsoyiannis,
IAHS co-Editor and Chairman of the Jury of the 2014 Tison Award

Dear colleagues and friends, ladies and gentlemen,

The Tison Award honours an outstanding paper of one or more young scientists, published in any of the IAHS publications and is now co-sponsored by Taylor & Francis, the publisher of Hydrological Sciences Journal. It was bestowed for first time 27 years ago, in 1987 in Vancouver, Canada, and the first recipient was Zbyszek Kundzewicz, now co-Editor of Hydrological Sciences Journal and IAHS. Since then up to 2013, the award has been bestowed 22 times on 37 young scientists from several countries belonging to all continents. Most of the laureates are now renowned hydrologists. To mention one of the most recent winners, the 2007 laureate, Christophe Cudennec, is now the IAHS Secretary General.

This year there was a strong competition, perhaps the strongest ever, as 16 papers were candidate for the award. The Jury, which I had the honour to chair, decided that the award goes to the paper “European precipitation connections with large-scale mean sea-level pressure (MSLP) fields” by David Lavers, Christel Prudhomme and David M. Hannah, published in the Hydrological Sciences Journal. Two of the authors are young scientists (under 41 years of age) eligible for the award: David Lavers and David Hannah. Perhaps if the review process were faster, the second author, Christel Prudhomme, would also have been eligible age-wise.

Both award winners are British scientists whose research focuses on hydrometeorology and hydroclimatology. David Lavers is a visiting scientist in the European Centre for Medium-Range Weather Forecasts in Reading, and has earlier worked as postdoctoral researcher in the University of Iowa in the USA and in the University of Reading in the UK. David Hannah is Professor of Hydrology and Head of the School of Geography, Earth & Environmental Sciences at the University of Birmingham. Despite his young age, he is already a renowned scientist with an impressive publication record recognized internationally.

The awarded paper investigates the spatiotemporal variability in gridded European precipitation and large-scale mean sea-level pressure, and identifies spatial relationships between rainfall and pressure patterns. For the first time, gridded rainfall and atmospheric pressure data were used to identify the detailed correlation structure between pressure and rainfall fields at a pan-European scale. By comparing the use of gridded data with that of indices, like the North Atlantic Oscillation Index, the study demonstrates the superiority of the former which yield stronger statistical relationships because the analysis of gridded data can capture the dynamic seasonal movement of the atmospheric areas with strongest control on European precipitation.

Prominent elements of the study are the huge gridded data sets it uses, the sound statistical methodologies it develops, which are suited to the big data sets and, consequently, the big extent and detail of the results presented. As the authors say, they had difficulties to present their results in figures, because they “cannot be reproduced in a larger format given the journal page layout”. Indeed, a more decent presentation would require large maps of the entire Europe, most of the Africa and the Atlantic Ocean.

The paper concludes with the following words: “The identified hydroclimatological relationships could be used to evaluate climate model output to determine if the location, strength and timing of these hydroclimatological connections can be reproduced accurately by models. If climate models become capable of reproducing these hydroclimatological correlation patterns at extended forecast lead times, scientific and societal benefits could result.”

By quoting these statements I wish to encourage the authors, as well as other colleagues dealing with similar research, to consider performing such studies and I invite them to submit their papers to Hydrological Sciences Journal.

Furthermore, I wish to add that the “if” clause in the above quotation may not be necessary. Scientific and societal benefits could result even if climate models are incapable of reproducing the patterns. Science is the pursuit of the truth, and the communication of the truth is beneficial to society whatever the truth is. In general, negative results are not to be glorified, but sometimes can be equally important and useful with positive ones, and sometimes even more important, when they falsify established theories or models. Therefore, my invitation stands for any type of sound scientific results for the follow-up of this important research.

In closing, I congratulate the authors and I wish them further scientific successes hoping that the Tison Award received from the International Association of Hydrological Sciences will help them achieve new heights in their careers.

The winning paper is:

Lavers D., Prudhomme C. & Hannah D. M., 2013. European precipitation connections with large-scale mean sea-level pressure (MSLP) fields. Hydrological Sciences Journal, 58 (2), 310-327. doi:10.1080/02626667.2012.754545



David Hannah

(Photo by Wovencontent)

David Hannah by Wovencontent


Thank you very much Professor Koutsoyiannis for those kind words.

It is a genuine honour to receive this award jointly with my friend and collaborator, David Lavers.

I am proud to have our names added to a list of such distinguished hydrologists and for us to be the 5th and 6th UK scientists to be honoured since the Tison Award’s inception in 1982. At the outset of this acceptance note, we must acknowledge the very significant inputs from our co-author Christel Prudhomme in designing, undertaking and writing-up this research. Indeed, the article is a real team effort because it was generated during David Laver’s PhD, which was an outstanding and exciting collaboration between the UK Centre for Ecology & Hydrology and the University of Birmingham.

As Professor Koutsoyiannis has just reviewed, our paper advances knowledge of the hydroclimatological processes connecting large-scale mean sea-level pressure to gridded European precipitation at the monthly time-scale. Importantly, this work shows that the location and extent of atmospheric centres of action (that drive precipitation patterns) are dynamic, varying in space and time, and that land surface relief modifies precipitation distribution further.

For me, this paper stems from a wider body of research that seeks to bridge the disciplinary gap between the atmospheric and hydrological sciences to better understand the interconnected climate and land processes that determine precipitation and river flow responses that, in turn, yield patterns of water availability and water-related hazards that impact on society and the environment.

There are a number of people that I must thank: for inspiring me to follow this path initially, and for collaborating so generously along the journey so far to develop my own thinking and generate new hydrological insights of value to the wider scientific community.

I am fortunate to have two fantastic mentors Angela Gurnell and Glenn McGregor; they kindled my interest in the influence of large-scale atmospheric circulation on hydrological processes during my PhD, when I researched the links between air-masses climatology and glacier runoff. I am grateful to Geoff Petts for persuading me to move from working in alpine environments and explorer temperate zone river flow and climate regimes as well as appointing me to a lectureship. Since then I have worked with a number of talented PhD and postdoctoral researchers (including David, of course!) to broaden my research interest in climate-hydrology interactions. I have gained inspiration from interactions with them.

As well as individuals, I have gained motivation, encouragement and support from two extremely important global initiatives and networks: the IAHS and UNESCO-IHP FRIEND-Water. I have benefitted considerably from my collaborations with colleagues in the IAHS International Commission for Surface Water. The FRIEND-Water cross-cutting theme of UNESCO-International Hydrology Programme has been instrumental in helping me build international research links and disseminate our findings through well-developed science, education and policy networks. I am thankful for FRIENDship from Lena Tallaksen, Henny van Lanen, Siegfried Demuth and Gregor Laaha amongst others.

I would like to thank my family (especially my wife, Angela, and my parents) for their constant support and encouragement, and our children Ellie and Ruby for keeping me young; and for IAHS recognising you are still young under the age of 41: a fact which the children have found both confusing and amusing(!).

Finally, I would like to thank our nominees for considering our paper worthy of submission and the jury for awarding us this prestigious prize from the IAHS against very strong competition. I am most honoured and appreciative in accepting. Thank you very much.

David Lavers

(Photo by Wovencontent)

David Lavers by Wovencontent


Thank you very much Professor Koutsoyiannis for your kind words about our research.

Ladies and Gentlemen, this really is a privilege to receive the prestigious Tison award jointly with my friend and mentor Professor David Hannah. To be added to a list of such notable hydrologists is a great honour.

The research presented in the paper was part of my PhD studies undertaken at the UK Centre for Ecology and Hydrology and the University of Birmingham. These results (in particular) formed the last section of the thesis, and brought together research ideas from over a three year period.

I am greatly indebted to my PhD supervisors Dr Christel Prudhomme and Professor David Hannah for their support, enthusiasm and friendship which helped me immeasurably throughout. I am richly blessed to have had such wonderful supervisors who gave me a springboard into academia. I am also grateful to Professor Eric Wood of Princeton University for giving me an opportunity to work in his research group during part of my PhD.

I would like to reiterate what David said, and thank the nominee for considering our paper worthy of submission and the jury for awarding us the Tison Award from the IAHS. Thank you very much.

See the full paper here


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