This opportunity to tell my story in a “Roads travelled by…” series makes me wonder: Does this mean I’ve arrived? I certainly don’t think so.
Often when asked to talk with a group of students, to tell my story, I start by saying that I have always been a “misfit”. Woman doing a physics PhD in the 80’s; physics-trained PhD then being recognized as an applied mathematician instead; physicist-turned-applied-mathematician next becomes a professor in a statistics dept. I could go on and on about all the ways I have felt like I didn’t “fit”. But what I really want to emphasize here is that a focus on who “fits”, or who doesn’t, is counter-productive. So many good questions, which are the most basic ingredient to research, may be lost if “fitting in” is perceived as a requirement for asking them. It also means that certain forms of curiosity and creativity, which may need “belonging” to ignite, don’t develop.
I’m currently a professor in the Statistics Department at the University of Chicago. I took this position in 2016 after 20+ years in Northwestern University’s Applied Math Department. Northwestern is just on the other side of the city of Chicago – I didn’t even move house with the job change. I was hired as part of a Computational and Applied Mathematics (CAM) initiative led by the University of Chicago’s Statistics Dept. – rather than being an applied math dept. with a statistics group in it, we are a statistics dept. with an applied math group in it. For the past 5 years I’ve served as the first director of U.Chicago’s “Committee on Computational and Applied Mathematics”. The “Committee” is comprised of faculty who support its interdisciplinary graduate programs. It’s been challenging, in a good way, to change academic cultures and my research environment after so long in one place. It’s also exciting to be part of something new, and to be supporting the goals of the students. I’m not expecting that I’ll make a big scientific breakthrough now, but I’d love it if I could claim some role in launching the career of someone else who does something amazing, especially if that relates to tackling a problem that matters for society and Earth, such as climate change.
At this stage in my career/life I prioritize working with people I enjoy, so we have some fun. I also get opportunities to work with people I deeply admire – inspiration isn’t in short supply. More than a decade ago, Chris Jones and Mary Lou Zeeman, two of those people I enjoy and admire, contacted me about their plans to draw more mathematicians into research related to climate change. They were creating a “math and climate research network”. My initial response was “you must have the wrong Mary Silber”; I didn’t see how my research, then on things like quasi-patterns (with Alastair Rucklidge), and time-delayed feedback control schemes (with Claire Postlethwaite), could be relevant. Chris and Mary Lou reassured me and made me feel welcome, and I spent the next ten years showing up to whatever they organized. I was also able to secure National Science Foundation (NSF) funding to take a sabbatical from Northwestern, to spend 2009-2010 embedded in the geophysics dept. at the University of Chicago. This was a helpful early orientation, while I struggled to figure out where to apply my dynamical systems expertise to problems in climate science. Another step in that direction involved teaching a project-oriented graduate mathematical modeling course, where I drew all the open-ended problems from Earth science applications, e.g. sea-ice, El Nino, vegetation patterns. One of the students in the class was Kaitlin Hill; she went on to do her PhD with me on the topic of Arctic sea ice modeled as a piecewise smooth dynamical system. Another student in the class was Karna Gowda; he went on to do his PhD with me on vegetation pattern formation in drylands.
As someone trained in pattern formation research, with Edgar Knobloch as my PhD advisor, the large-scale vegetation patterns, which are beautiful and can be remotely monitored by satellites, captured my attention. It helped to have Karna Gowda as my student, and Sarah Iams as my postdoc, at the time I started down that research path. Karna and Sarah are both (a) fun, (b) inspiring. They are the type of applied mathematicians who are foremost scientists, and science is what drew me to applied mathematics in the first place. Karna insisted on looking at what the data say – not just what the models predict. Eventually, he was so committed to listening to the data that, as a postdoc, he switched to doing laboratory experiments in microbial ecology. While Karna has dived into the soil to investigate microbial communities, a smaller shift has happened for me. Together with my collaborator Punit Gandhi, I’m now thinking a lot about the water, which is the limiting resource, for the vegetation. How does it flow over the landscape after rare and unpredictable rain storms? How does this short-lived process of redistribution of resource dictate the consumer distribution pattern? Of course, the vegetation is not some passive tracer; this is all complicated by nonlinear feedbacks, essential to the pattern formation process. To what extent are vegetation patterns in drylands tuned to the rainfall patterns? Are there ways for us mathematicians to harness the natural spatial and temporal heterogeneity to learn more about this beautiful phenomenon? I hope it’s not too bold to say “stay tuned”.
The SIAM Activity Group in Dynamical Systems has been my intellectual home for the past ~30 years. As with any good home, I have always felt welcome.
Vegetation patterns, figure and caption reproduced from K. Gowda, S. Iams and M. Silber, “Signatures of human impact on self-organized vegetation in the Horn of Africa” Scientific Reports 8 (2018).
Author, from graduate school days, shown in the Berkeley hills (~1985).
Author in her Hyde Park backyard, with her circa 2016 research group; left to right are Karna Gowda, Sarah Iams, (Mary Silber), Kaitlin Hill and Yuxin Chen.
Author’s blackboard (and the author), taken by a student during office hours, Fall 2021.