By Zhengzheng Zhang
Doing a postdoc abroad is a big decision. The opportunities are as diverse and plentiful as the challenges. One postdoc’s desire to improve people’s lives sent her on an adventure to the other side of the Atlantic Ocean.
After completing her Ph.D. studies in 2011 at Météo-France, the French national meteorological service, Anne-Sophie Daloz accepted a postdoc position at UW-Madison’s Cooperative Institute for Meteorological Satellite Studies (CIMSS) where she has continued her research on tropical cyclones and climate change.
Having faced the challenges of living and working abroad, Daloz reflects on her two years’ experience at CIMSS as one of the most important and valuable training opportunities of her career. It allowed her to work and study with leading scientists in the field, establish new international collaborations, and learn from the exposure to a different working environment.
“I want to do science that can be applied to people,” Daloz says. “Tropical cyclone research is an area that matters and one where you can help people.” Originally a physicist, Daloz turned to the study of tropical cyclones and Atlantic climate variability during graduate school. Since 2012, under the mentorship of NOAA/CIMSS scientist Jim Kossin and Atmospheric and Oceanic Sciences professor Dan Vimont, she has focused on examining and evaluating the ability of different climate models to accurately represent tropical cyclone behavior.
“Tropical cyclones are one of the most devastating phenomena in the world due to their strong winds and heavy precipitation extending over wide areas. It is very important to better understand and simulate the characteristics of tropical cyclones,” says Daloz. “Our goal is to predict how tropical cyclones could evolve in the future. But first, you have to assess the capability and reliability of different climate models to make sure they can accurately and realistically represent tropical cyclones.”
A realistic simulation of tropical cyclones in both size and intensity requires high-resolution models. Unfortunately, the spatial resolution of most climate models, like global climate models that are used for climate studies and projections, is too coarse to adequately resolve these storms, especially the most intense storms. While the low-resolution climate models can produce tropical cyclone-like storms, some of the characteristics such as size and intensity, differ from the actual observations. To meet these high-resolution requirements, climate scientists have developed several downscaling techniques to produce local-scale surface weather from global climate models outputs.
“One benefit of the downscaling technique I examined,” Daloz says, “is the ability to generate a large number of synthetic storm tracks with realistic intensity estimates.”
Daloz compared characteristics of explicit and downscaled models to represent the tropical cyclone tracks from the North Atlantic basin. The explicit tracks are obtained directly from tropical cyclones simulated in regional or global climate models, and the downscaled tracks are from cyclones simulated using the downscaling technique from climate models.
“Our research shows that except for seasonality, that is, how tropical cyclones recur every year, the downscaled tracks do a better job of capturing other observed characteristics of tropical cyclones like intensity, landfall probability, duration and frequency,” Daloz notes. “Global climate models are good, but sometimes they have limitations, for example, in representing the intensity of tropical cyclones. So, downscaled models can be a good complement for global climate models.”
Daloz has also studied the influence of sea surface temperature (SST) and carbon dioxide on climate variability–whether an increase in these factors will lead to future changes in frequency and intensity of North Atlantic tropical cyclones. Daloz and her coworkers confirmed previous studies showing that the response to each scenario can depend significantly on the choice of climate models and simulations.
“All of our efforts are aimed at making the models better represent tropical cyclones and to improve our ability to predict what could happen in the future. If models converge to show the same representation of the current climate as in the observations, we may expect that they probably can give a good presentation of future climate. If not, then we will need to check our models to improve them. If we can predict changes in location or intensity of tropical cyclones, then we can better protect people from disaster,” Daloz explains.
Daloz’s analysis work is based on the model simulations produced by the U.S. Climate Variability and Predictability Research Program (CLIVAR) Hurricane Working Group.
Daloz also appreciates the collaboration opportunities provided by her mentor Jim Kossin and Daniel Vimont. She is impressed with the research environment at CIMSS where communication is central to scientific research.
“I really enjoy the opportunities at CIMSS to work with CLIVAR, attend conferences every week, listen to interesting talks and share information with others. In France, it’s not as easy to interact with so many people. There are many more scientists in the U.S. who are studying tropical cyclones. The professional pool here is huge. You can have much more scientific interaction here than any other place.”
But opportunities also come along with challenges. As a foreign scientist, visas, housing, schools, childcare, and employment for one’s partner all require considerable time and energy to arrange. Over time, Daloz has adapted to living and working in the United States.
“In France, we have longer working hours per day but more holidays for social life; the case is reversed in the U.S.,” she says. And, the language can be challenging.
“Although I don’t think my English is too bad, if you speak at a conference, you still get nervous. Also, you have to meet people to establish a new collaboration. A small example–in France, I was running my own climate model, so I was providing my own data. But here, I had to ask people for data. At the beginning especially when not a lot of people know you and your English is not that effective, it can be hard to communicate and collaborate,” Daloz says. “But I feel lucky because Jim and Dan have helped me with communication and building professional networks across the international border.”
Summing up her experiences over the past two years at CIMSS, Daloz says going abroad has allowed her to work with leading tropical cyclone scientists and learn to work in a different environment. The curiosity, adaptability, problem-solving, and open-mindedness necessary to work and live abroad are all valuable qualities for postdocs preparing for their next professional position.
Daloz will continue her work at CIMSS for the next year and get involved in more projects. Ultimately, she plans to return to France and would like to work at the Institut de Recherche pour le Développement, an organization dedicated to interdisciplinary research emphasizing the relationship between man and environment in African, Mediterranean, Latin American, Asian and the French tropical overseas territories.
“I would like to bring a broader international network and different tropical cyclone research experience, which could be an advantage for the organization. I also wish to help with climate research in developing countries,” Daloz says.