Besides his outstanding personal contributions in research, Dr. Brutsaert has made a lasting imprint through the unselfish cooperation he embodies in all his activities. First, this is brought out by the professional success of his former graduate students, who have benefited from his generous and devoted collaborative mentorship in research. Second, since the early 1980s, Dr. Brutsaert has been a worldwide leader in bringing together the hydrologic and atmospheric research communities in the planning, design, and operation of large-scale international field experiments. Finally, Dr. Brutsaert has shown exemplary service commitment to his colleagues. Most notably, he has been directly involved in leadership in several organizations, including AGU, the American Meteorological Society (AMS), and the National Academy of Engineering (NAE).
Some highlights of his research contributions can be found in the following areas: (1) Physics of evaporation: Dr. Brutsaert was the first to successfully incorporate the effect of molecular diffusivity in the description of evaporation and heat transfer in the environment. (2) -Land--atmosphere interactions: He has largely unraveled the issue of scaling in evaporation, from local scales to various macroscales. (3) Surface runoff: Dr. Brutsaert was the first to provide a realistic description of base flow using groundwater theory rather than by regression or curve fitting. (4) Porous materials: He extended Biot’s theory of poroelasticity to materials containing two fluids, as found in petroleum engineering. (5) Climate change: Dr. Brutsaert is one of the few who have clarified hydrological aspects of global climate change. His 1998 paper in Nature resolved the “evaporation paradox” with evidence of a worldwide accelerating water vapor cycle. Later, he initiated a radically new method to deduce climatic trends from long-term river flow records.
In addition to his articles are his two landmark scholarly books, both international best sellers: Evaporation into the Atmosphere (Springer, 1982) and Hydrology (Cambridge University Press, 2004).
Among the many awards he has received, he was elected to the NAE, AGU awarded him the Hydrologic Sciences Award and the Horton Medal, and the AMS awarded him the Jule G. Charney Award and elected him an Honorary Member, its highest award. The Japan Society of Hydrology and Water Resources awarded him its International Award and made him an Honorary Member. The Japan Society for the Promotion of Science gave him the Award for Eminent Scientists.
In conclusion, it is difficult to imagine a colleague more deserving of the Bowie Medal.
—Jean-Yves Parlange, Cornell University, Ithaca, N.Y.
“The Horton Medal is for ‘outstanding contributions to geophysical aspects of hydrology.’ By any measure chosen, Wilf Brutsaert is most deserving of this honor.
“I first met Wilf in 1981 when we worked together on the editorial board of Water Resources Research. I quickly came to value his wise counsel and friendship and the depth and breadth of his scholarship. He is extremely generous with his time for family, friends, students, and colleagues. He provides intellectual leadership to the community through his personal scholarship and collaborations. He brings the enthusiasm of the brightest and most energetic, recently graduated Ph.D. to all that he does. His decades of leadership within AGU and in numerous activities that have yielded scientific opportunities for many have been absolutely selfless.
“Wilf has investigated primarily the fluid mechanics of environmental phenomena to solve critical problems of hydrology. His research constitutes a perfect balance of theory with careful and appropriate experiments. He has published pioneering and lasting papers on vadose-zone and hillslope hydrology, gas exchange at air-water interfaces, and aquifer dynamics. He is best known, however, for his original and incisive contributions in the description of the transport of vapor through the Earth-atmosphere boundary layer and has been at the forefront of establishing programs that make the best use of both groundbased and remote platform measurements to quantify evapotranspiration. As an example of his influence, authors now refer to one of his similarity schemes as the ‘Penman-Brutsaert’ approach.
“Wilf writes beautifully, never overstating the case, and always places the situation into perspective. There are several examples that highlight the breadth and depth of his work on evapotranspiration. His 1976 paper with Mawdsley, The application of planetary boundary layer theory to calculate regional evaporation, revolutionized the use of atmospheric boundary layer fluid mechanics to estimate regional evapotranspiration. His 1986 paper, Catchment scale evaporation and the atmospheric boundary layer, provided the foundation for the direction of significant ongoing research by many colleagues. The 1992 paper with Sugita, Landsat surface temperatures and radiosoundings to obtain regional surface fluxes, and the 1996 paper written with Qualls, Evaluation of spatially distributed ground-based and remotely sensed data to estimate spatially distributed sensible heat fluxes, demonstrate his penchant for tackling ‘wicked,’ real-world problems. His 1998 Nature paper with Marc Parlange on the Evaporation Paradox resolves a thorny problem in hydrology and a key issue in the current global change debate.
“Wilf cares deeply about and makes the considerable effort to research the history of our field. An example is from his 1992 AMS Horton Lecture, Horton, pipe hydraulics and the atmospheric boundary layer (Bulletin of the American Meteorological Society, June 1993) in which he traced the theoretical developments of the atmospheric boundary layer methods used to estimate vapor transport from large land areas. He identified the critical measurements supporting the early theoretical developments of Blasius and Prandtl as those conducted in 1902-1903 at the Hydraulics Laboratory at Cornell University, Wilf’s academic home, to determine resistance to water flow in pipes. (Robert Horton worked with the research staff, Saph and Schoder, soon after they completed this work.) Before Wilf’s lecture, few knew about the early fundamental measurements underpinning this theory.
“Marc Parlange summed up Wilf’s work: ‘He has done it all in hydrology. He has carried out brilliant research in numerical and analytical methods for partial differential equations describing environmental transport, he has collected precious laboratory and field measurements which remain benchmarks for theoretical comparisons, and he has developed foundational theories for the description of regional hydrology and land-atmosphere vapor exchange. No physical hydrologist has ever touched so many areas in such depth.’ Kuo-Nan Liou commented that Wilf’s 1982 book on evaporation into the atmosphere ‘has been and is still considered by many scientists in atmospheric and hydrological disciplines to have provided the physical foundation for the connection of the land surface and atmospheric boundary layer.’ Jeff Dozier observed that this ‘is the best reference book on my shelf.’
“Wilf Brutsaert embodies all that is good about AGU, is the complete academic scholar-teacher and research scientific leader, and exemplifies ‘unselfish cooperation in research.’ President Knauss, ladies and gentlemen, it is a privilege and honor to present my friend and colleague, the winner of the 1999 Horton Medal, Wilfried Brutsaert.”
—STEVEN J. BURGES, University of Washington, Seattle