HS
Hydrological Sciences

YHS interview Martyn P. Clark: “rainfall-runoff modelling, per se, is dead”

In its “Hallway Conversations” series, the Young Hydrologic Society has recently published an interview with Martyn P. Clark, who is currently professor and the Associate Director of Centre for Hydrology and Canmore Coldwater Lab, at the University of Saskatchewan, Canada. The interview was conducted by Sina Khatami, a PhD student at the University of Melbourne. With their agreement, we reproduce below some short extracts of the interview. For the full interview, visit the YHS Blog (here).

Martyn Clark did his undergraduate degree and his Master degree at the University of Canterbury, in New Zealand, and was awarded a PhD degree by the University of Colorado in Boulder. After working back in New Zealand for a while, he came back to the US in 2010 to work at NCAR. You can check the interview he gave to HEPEX in 2016, while in Boulder (see here). In December 2018, he moved to University of Saskatchewan, where he is currently working with new challenges ahead.

Your research spans across a wide range of domains of hydrology, hydro-climatology and model development. How did you expand your knowledge and expertise so widely?

In the early days, it was more of a random walk. My interests evolved into different areas and I pursued opportunities where they were. I read a lot. Even when I was doing my master thesis, I read and read and read. So, I was able to get a fairly good understanding of the literature and identify what the major science questions are. Later on in my career, I’ve been much more strategic than tactical as I was in early stages of my career: thinking about what the big problems are that we want to solve, and how we can go for the funding opportunities out there that lead more towards this larger vision… more of a proactive approach, than a reactive one.

Over the past few years, you’ve become the Editor-in-Chief of WRR (see the EoS interview), moved from public sector (NCAR) to academia and from Colorado to the Canadian Rockies. Each of these decisions are big enough to be a challenge for a few years. So, first, how’re you holding up [I laugh]? And what motivated such major changes?

Well these were more sequential than simultaneous [we laugh]. So, let’s deal with them sequentially. I was asked to apply for the Editor-in-Chief position for WRR. They had a search committee together and they asked me if I would consider doing it. My initial response was no. Then I thought about it for a while. Two things had happened in that year. First, I was promoted to senior scientist at NCAR, which is the top level there. So, I didn’t have any opportunities for additional promotion. And also, I was elected as Fellow of AGU. So, I thought I have kind of established myself in my career and perhaps now is the time to give back to the community more. And there was this opportunity. I was weighing all of my commitments and then thinking about how I could push the field forward. And I thought, well… what good can I do? I thought if I publish, say, two fewer papers a year and be the WRR Editor-in-Chief instead, I can probably do more good and continue along my current trajectory. I was also keen for a new additional challenge.

NCAR is federally funded research and development centre and received a lot of its funding from government and through NSF (National Science Foundation in the USA). The decision to move to the University of Saskatchewan was in part because I wanted the broader challenges that comes with the university setting. And it was in part because of the funding that they already had in place with the Canadian government as part of the Global Water Futures (https://gwf.usask.ca/) programs. This really provided the opportunity to achieve a lot of my research ambitions that I’ve had for many years.

Reviewing and handling numerous papers as WRR Editor-in-Chief has provided you with a big picture of the research community. How is that is influencing your own approach to defining new questions, particularly for your new career line at University of Saskatchewan.

Yes. For my new career at the University of Saskatchewan at Canmore, a wonderful location by the way, we are building up the research program there (https://uofs-comphyd.github.io/). A lot of the research thrusts and the global water futures program are the things that I have been working on over the past twenty years anyway. It is dominated by two main application questions: (1) improving streamflow forecasting methods, and (2) improving assessments of impacts of climate change on water security. Those are the two applied questions that have guided my research on process understanding, model development, strengthening the link between algorithms and theories, etc. It is not as if I’m going to a new research area; I’m going into an area where I have had an extensive presence for a very long time. So, that part of it is not new. But the part that is forcing me to extend myself a little bit is that the funding available is more than an order of magnitude larger than what I ever had before. So, being able to think more strategically, like build up a large cadre of postdocs to answer these questions, or how to orchestrate a large research program — it is really exciting.

Looking back at your research career, what do you think your major breakthroughs are and why?

I think my major breakthrough is quite broad. But I can list some specific papers if you want. Developing a more structured approach to hydrological model development is something that I’ve been working on for many years. The first paper that I really published in that area was my FUSE paper, working with bucket style models. Then my most recent big modelling paper was my SUMMA paper (paper 1 & paper 2) [both are modelling frameworks that allow a user to analyse the impact of individual modelling decision; such as the choice of model structure, the choice of specific flux equations, and the choice of numerical method with which to solve the model equations].

How do you describe your research style? Or, what are the main elements for you when you’re impressed by a piece of research?

For me, personally, I’m really interested in making a step change in our understanding of modelling capabilities. So, most of the major papers that I’m proud of have had a gestation period of more than five years. And so, if you look at my publication history — it’s kind of interesting — I had no first-author research publications in the time period of 2011 to 2015, when I was developing SUMMA. And that can be a little bit dangerous [he laughs] for people at earlier stages of their career. I really wanted to make a major contribution in the way that we develop models. I was worried that a lot of our model development was somewhat ad hoc and we didn’t have the structure that we needed in order to really understand where and what model weaknesses are. I was worried that model evaluation wasn’t done in a controlled way and that we really needed a new framework in order to push forward in those areas.

What would you identify as the main gaps or big picture questions of hydrological sciences for the coming decades that you think early career scientists can pursue?

I think we really need to evolve towards a more interdisciplinary Earth System Science approach to modelling. For many years, hydrology has been rooted somewhat in what was called rainfall-runoff modelling. That term is not really applicable anymore, because we now are modelling a large number of complex interrelated processes in the terrestrial water cycle. So, multi-process modelling in an Earth System modelling context, not just focusing on the short-term fluxes but also the longer-term evolution of our systems. Understanding the evolution of soils in the catchment, understanding the evolution of vegetation in the catchment and understanding how those slowly varying processes feed back on to the higher frequency variability, which has typically been the domain of hydrologists.

And this goes back to the SUMMA paper that you mentioned?

Well that’s just a part of the bigger picture. SUMMA has a more complete representation of the terrestrial hydrological cycle than many hydrological models. But many models already have that level of complexity. SUMMA doesn’t even begin to get into the issues of bio-geochemistry, catchment co-evolution, etc., which are going to be really important. What SUMMA does is provides a structured template for process-based hydrological models which can be extended into the Earth system modelling framework. But it’s nowhere near complete enough of what we need moving toward. So, what I’m talking about is not something that we can do in the next couple of years but something that we need much more concerted effort over the timescales of several decades.

Are there any papers or books that you would like to recommend on this grand idea of expanding the spectrum of processes within current hydrological models towards Earth system modelling?

The first part of the SUMMA paper provides some beginning thoughts in that area but it doesn’t go as far as it needs to. We wrote a paper on improving the representation of hydrological processes on Earth System models. That’s really just beginning to scratch the surface as well. I think the paper that everybody should read is the one led by Ying Fan on providing the link between hillslope hydrology and Earth system modelling that provides lots of pointers in that direction. But it’s funny that you ask that. There’s something that I’ve been kind of stewing on for a while, which is to put together a coherent commentary paper that emphasizes that as a research direction that’s necessary.

You’ve pointed out many great things so far, is there any other advice you may have for young hydrologists?

I think I’ve covered a lot of it already. Be bold. Think about how you can really make substantial advances in the research frontier. Be strategic. You need the incremental progress. You need the intermediate scale products as you are conducting your research so that you can feed the beast [he smiles] and work effectively through the career track. But those intermediate scale products need to be conducted within the context of a larger scale vision. So, really think about defining that vision. Talk about that with your colleagues and keep refining that. And having an idea how your career contributions will really begin to make a difference.

Some guidance would be to think about three levels of strategic planning or technical planning in some respects: (1) what do you want to accomplish in your career? In terms of always keeping that and the longest timescale. (2) What’s the thing that you’re going to present at the next conference? Most people are thinking about those two or perhaps not giving as much attention to the vision aspects as they should. But the third that often gets neglected based on my interactions with people is (3) what are you going to do tomorrow, and the coming week? So, basically organising your activities on the shorter timescale, so that they are feeding the ambitions that you have on the longer timescales, I think is really important.

This might be a somewhat stupid question. Do you have any measures to evaluate a good PhD or postdoc? Like the number of their publications or good publications in a year, etc.

Yeah, this has been my problem. I don’t like the way that people are being judged in academics. There’s a saying that managers know how to count but they don’t know how to read [we both laugh]… In the sense that people are focused too much on outputs, like how many papers you published, than outcomes. I think that things are going to change. I wrote an editorial in WRR on the citation impact of hydrology journals. There I was talking about the need to shift away from quantitative assessments to more qualitative assessments to really begin to measure how people are making a difference in the community. For me that’s the major thing. So, if we get back to what would help people get a job, I can tell you what I’m looking for. Yeah, you need some papers to get on people’s radar screen. If you have finished your PhD and you don’t have any papers then that’s a red flag. But what you really need, in my mind, is to be known for something. That people look at you and say okay that person has done X, or that person has accomplished Y. So, the number of papers that you’ve written become less important. So, what I’m looking for is what have you done to make a difference in the community. And that’s what a lot of other people are beginning to look for more.

I’m curious to know more about this. How would this qualitative assessment process work, to assess the impact of a person on hydrological sciences or even the broader geosciences?

You should read the Declaration on Research Assessment (DORA), which I also referred to in our 2017 editorial paper. DORA comes up with a set of guidelines for funding agencies, universities, managers, etc. to show how they can move towards research assessment practices that are more fair. It has been picked up by a lot of different institutions and universities. A lot of it is there. It’s more just changing the structure of the research assessment. You know there’s not going to be one size fits all template that people can use, but structuring it in a way that emphasises the contributions rather than the specific papers. It takes more work, but we should value our colleagues and take the time to really make sure people’s efforts are directed in productive ways.

 

Note from the EGU HS Blog Editorial team: In the past EGU 2019 GA in Vienna, EGU organized a debate on “Rewards and recognition in science: what value should we place on contributions that cannot be easily measured”, where DORA was also debated, among others. 

Guest author Sina Khatami is a PhD student at the University of Melbourne (Australia). He is interested in hydrological modelling, uncertainty, and philosophy of science. In his PhD project, he developed a process-based model evaluation method, called Flux Mapping, to gain insights into the internal dynamics of conceptual models. He is also the current Secretary of Young Hydrologic Society and a student member of AGU’s Hydrology Section Hydrological Uncertainty Technical Committee.

Edited by Matthias Sprenger and Maria-Helena Ramos

Avatar
This guest post was contributed by a scientist, student or a professional in the Earth, planetary or space sciences. The EGU blogs welcome guest contributions, so if you've got a great idea for a post or fancy trying your hand at science communication, please contact the blog editor or the EGU Communications Officer to pitch your idea.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

*