Liang, Xu
Xu Liang
Dr. Xu Liang is an internationally recognized professor at the University of Pittsburgh’s Swanson School of Engineering. Dr. Liang’s research has contributed significantly to land surface modeling, and she has advanced the understanding of ecosystems and their water, energy, carbon, and nitrogen cycles. Dr. Liang also researches the interactions of these cycles and their effect on environmental health and ecological systems. Her research includes investigating how ecosystem cycles influence nutrient and pollution transportation, human health, food security, and water resources management.
“When you see the success of other people, what you do not see is how hard they have worked and how much they have gone through” - Dr. Xu Liang, 2023
Villalba, G.A., Liang, X., & Liang, Y. (2021). Selection of Multiple Donor Gauges via Graphical Lasso for Estimation of Daily Streamflow Time Series. Water Resour. Res., 57(5). American Geophysical Union (AGU). doi: 10.1029/2020WR028936, (29 pages).
Salas, D., Liang, X., Navarro, M., Liang, Y., & Luna, D. (2020). An open-data open-model framework for hydrological models integration, evaluation, and application. Environmental Modelling & Software, 126, 104622.Elsevier BV. doi: 10.1016/j.envsoft.2020.104622, (20 pages).
Luo, X., Liang, X., and McCarthy, H.R. (2013). VIC+ for Water-limited Conditions: A Study of Biological and Hydrological Processes and Their Interactions in Soil-Plant-Atmosphere Continuum. Water Resour. Res., 49, doi: 10.1002/2012WR012851, (22 pages).
Parada, L. M., and Liang, X. (2004). Optimal multiscale Kalman filter for assimilation of near-surface soil moisture into land surface models. J. Geophys. Res., 109(D24), doi: 10.1029/2004JD004745, (21 pages).
Liang, X., Lettenmaier, D.P., and Wood, E.F. (1996). A one-dimensional statistical dynamic representation of subgrid spatial variability of precipitation in the two-layer variable infiltration capacity model, J. Geophys. Res., 101(D16), 21,403-21,422.
Dr. Liang grew up in a family of educators. Her father was a university professor, and her mother was a school teacher. Her grandfather was also a renowned professor. From an early age, her parents instilled in her the value of education. They taught her to work hard, to develop an outlook on life with values grounded in kindness, integrity, and humility, and to have ambitious aspirations to contribute significantly to society. The two fundamental teachings she learned from her parents are: 1. To contribute to the betterment of society, and 2. To strive for a good education to excel in science and engineering.
Dr. Liang’s parents also taught her how to overcome difficulties. They shared with her, “When you see the success of other people, what you do not see is how hard they have worked and how much they have gone through.” She frequently reminds her and her students of this philosophy.
Dr. Liang attended Sichuan University, formerly Chengdu University of Science and Technology, in China, where she earned a Bachelor of Science in Engineering and a Master of Science in Engineering. Dr. Liang then moved to the United States and a second master’s degree in Environmental Science and Engineering from the University of Washington in Seattle. In 1994, Dr. Liang completed her Ph.D. in Hydrology and Water Resources from the University of Washington.
Dr. Liang is a leader in surface water hydrology and is internationally known for her significant contributions to land surface modeling research. She actively engages in interdisciplinary collaboration work with atmospheric scientists, plant biologists, and computer scientists.
Dr. Liang’s environmental and academic career path was strongly influenced by her compassion for human beings and by her family, as both of her parents are educators. After completing her doctoral work, Dr. Liang accepted a postdoctoral researcher position at Princeton University with a colleague of her advisor. Traveling to the opposite coast, Dr. Liang worked in the Department of Civil and Environmental Engineering at Princeton University. While there, she further developed the Hydrologically based Variable Infiltration Capacity (VIC) land surface model. Dr. Liang was instrumental in the model’s construction and continues to work on and develop the model.
At Princeton, Dr. Liang designed Phase-2C experiments for the Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) and organized an international workshop on PILPS Phase-2C with her advisors. The PILPS Phase-2C Intercomparison Experiment was the first one under PILPS that intercompared the current generation of land surface models at a regional scale. The international workshop allowed professionals to work together to assess the strengths and weaknesses of land surface models.
After her postdoctoral research fellowship at Princeton, Dr. Liang accepted a research scientist position at the Joint Center for Earth Systems Technology, NASA/University of Maryland.
In 1998, Dr. Liang accepted a faculty position at the University of California, Berkeley. She has an ambitious goal to discover fundamental laws that govern water and energy cycles with the hopes of better understanding how water and energy cycles affect the health of our environment and ecological systems, how they influence the transport and cycling of nutrients and pollutants at different spatial scales, and how to improve prediction accuracies of weather, floods, and droughts. Dr. Liang concentrates on various areas, including surface water and groundwater interactions and their impacts on land-atmosphere systems, scaling and data assimilation, feasible representations of physical and hydrologic processes across different spatial scales, model parameter estimations, and hydroinformatics. Additionally, Dr. Liang studies interactions between water, soil, and pollutants and the impacts of non-point source pollution transport on hydrologic and ecological systems at the watershed scale.
Dr. Liang’s work is critical as she strives to develop quantitative frameworks that connect the processes of different spatial scales across the atmosphere-vegetation-land-soil continuum. These connections will further understand the intricacies of interactions and feedback among atmosphere, vegetation, land, and soil as an integrated system. Her research has resulted in numerous publications and recognitions, including the selection of the VIC model by the North American Land Data Assimilation Systems as one of the four models and the only one from academia. Dr. Liang’s accolades include over 13,400 citations of her refereed journal papers.
Dr. Liang places equal importance on her teaching and mentoring responsibilities as she does on her research on land-type interactions. When she arrived at UC Berkeley in 1998, there were no other surface water hydrologists in the department. Thus, Dr. Liang’s task was to provide students with stronger hydrology courses and develop a surface water hydrology program in the department. In 2000, Dr. Liang received the Hellman Foundation Junior Faculty Research Award for Excellence in Research from the University of California-Berkeley.
In 2006, Dr. Liang embarked on a new challenge as she moved to the University of Pittsburg to lead the surface water hydrology program. Dr. Liang researches land surface hydrology and modeling, data assimilation, data analytics and hydroinformatics, machine learning, cyberinfrastructure data integration and model systems, and wireless sensor networks for hydrological sciences. Dr. Liang received the 2014 Carnegie Science Environmental Award; in 2016, she received the University of Pittsburgh Chancellor’s Distinguished Research Award. In 2016, Dr. Liang was elected as a fellow of the American Meteorological Society.
Recently, she has led an interdisciplinary multi-institution team to build a novel and open cyber-infrastructure framework called CyberWater/CyberWater2. It is a sustainable and easy-to-use Open Data and Open Modeling framework developed to remove as many barriers as possible for water communities. CyberWater/CyberWater2 makes it much easier to conduct large-scale collaborations across heterogeneous computing platforms, disciplines, and organizations to solve large and complex problems that previously could not be efficiently and adequately investigated.
The CyberWater framework simplifies diverse data and model integration with little coding. It supports high-performance computing (HPC) on demand, models system reproducibility, reusability, and easily integrates other systems with CyberWater. It also provides tools, such as a generic model agent toolkit, for the user to construct model agents that integrate their models with the CyberWater system without coding. In addition, CyberWater provides tools through its static parameter agent toolkit to automatically generate model parameter input files with various file formats to facilitate the time-consuming and error-prone data and model parameter files pre-processing process for diverse models.
Dr. Liang has made clear contributions to the field of hydrology; however, the path has not always been easy. She has dedicated tremendous energy to convincing people of the importance of surface water hydrology and water resources - energy she could have used to create solutions to environmental problems. Nonetheless, Dr. Liang believes everyone will encounter challenges, but with strength and a love of the research, “we will be able to overcome the challenges.”
Dr. Liang’s work has been influenced and assisted by many great hydrologists, including her advisors. They provided tremendous support and encouraged her to pursue a career in academia. She especially appreciates their support of her as a foreign woman in science and engineering. The academic environment can be very challenging, and Dr. Liang found it crucial to have a supportive environment. She feels fortunate to know and have the support of so many hydrologists and atmospheric scientists.
She is grateful for the support of many people, including her parents, her Ph.D. advisors, Dennis Lettenmaier and Stephen Burges, and her postdoctoral advisor, Eric Wood. She also acknowledges many other influential colleagues and mentors from UC Berkeley, UC Santa Barbara, Princeton University, University of Arizona, and Cornell University for their dedication to science and incredible societal contributions. Some of the people she mentioned include Thomas Dunne, Garrison Sposito, James Smith, Ignacio Rodriguez-Iturbe (deceased), Efi Foufoula-Georgiou, Soroosh Sorooshian, W James Shuttleworth (deceased), Wilfried Brutsaert, Inez Fund, and William E. Dietrich.
Dr. Liang has also been a mentor to many students and visiting scholars. While at UC Berkeley, she graduated four Ph.D. students and advised another three Ph.D. students until they graduated, even when she was no longer at UC Berkeley. Altogether, Dr. Liang has graduated 18 Ph.D. students. Some of them are now senior engineers, research scientists, faculty members, and entrepreneurs across sectors and around the world. In addition to graduate student mentoring, she is proud of mentoring undergraduate students through her NSF-funded Research Experiences for Undergraduates (REU) grants. She teaches her students to have the right attitude toward research. To her mentees, she says, “You have to be curiosity-driven, interested, and prepared to overcome hurdles. It is not supposed to be easy.”
Dr. Liang strives to recruit women and minority students to the program. About 50 percent of her graduated Ph.D. students are women and minority students. Further, she encourages students to take classes outside the department to strengthen their interdisciplinary knowledge and understanding of environmental processes. Under her guidance, two students received the prestigious Berkeley Atmospheric Science Center Research Award three times, and one student received the Outstanding Student Paper Award in 2009 at the American Geophysical Union Joint Assembly – The Meeting of the Americas, Toronto, Canada.
Further, she actively encourages middle and high school students to participate in programs sponsored by the National Science Foundation (NSF). With support from the NSF, Dr. Liang co-organized three summer science camps with her collaborators using their developed real-world wireless sensor network testbed at the Beechwood Farms Nature Reserve in western Pennsylvania. The summer camps enhanced the students’ interests in science and engineering, especially in sensors, environment, and water. Each time, about half of the participants were female students. Dr. Liang believes hydrology is an excellent field with a bright future and encourages everyone to pursue a water-related career.
Dr. Liang is a hands-on advisor. She spends one to two hours each week per student on individual meetings to discuss their research progress, problems encountered, and to illustrate research approaches and concepts, connecting the dots with broader science and engineering perspectives. It occupies a significant amount of Dr. Liang’s time, but she believes providing students with the big picture is a more effective way to educate them. It helps students develop a critical and comprehensive understanding of the research by knowing their results and interpreting the reasons. While it may take less time for Dr. Liang to give her students only the basics and ask them to figure out the rest, she feels that makes it harder for students to become independent and mature researchers and engineers. She hopes to share with them essential skills and training on how to research to avoid common mistakes and unnecessary detours in scientific research. In addition to the scientific training, “It is important to train students to take responsibility and to share responsibility. It is our task to train students to become a good person in many different ways.”, says Dr. Liang.
Many of her students have kept in touch with her and sent her thank-you notes for the training they received from her.
Dr. Liang stresses the importance of thinking about and setting up longer-term goals. She believes breaking big, long-term problems into smaller components can help solve long-term goals and projects more effectively. She says, “Nothing is easy. You can’t achieve big goals in a short period of time. A lot of challenges require a constant and persistent attitude.
She added, “It is important to identify important problems and not be afraid of challenges. Nowadays, all sciences are moving toward interdisciplinary training. Young people have to step out of their comfort zone and learn to work with others.” Dr. Liang also recognizes the biases and incompleteness in evaluating success. For instance, academia focuses on the number of publications and citations, whereas other industries rely on dollar values to measure success. However, these are not helpful measures for long-term goals.
Dr. Liang encourages individuals to look into pressing issues that need to be addressed for the benefit of our society and work on a step-by-step process to manage them. Lastly, Dr. Liang reminds young professionals that quality output takes time.
Research.com. 2023. Xu Liang. Retrieved July 25, 2023 from https://research.com/u/xu-liang.
Survey and interviews conducted by Justice, Equity, Diversity, and Sustainability Initiative staff. 2022-2023. Yale University-School of the Environment. New Haven, Connecticut.
University of Pittsburgh. 2021. Xu Liang. Retrieved July 25, 2023 from https://www.engineering.pitt.edu/people/faculty/xu-liang/. University of Reading. N.d. Meet the Team: Xu Liang. Retrieved July 25, 2023 from https://research.reading.ac.uk/lemontree/meet-the-team/.