Joseph A. Zehnder, Ph.D. |
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Joseph A. (Joe) Zehnder was born, raised and educated in the city of Chicago, Illinois. He attended the University of Illinois at Chicago majoring first in pre-veterinary medicine and switching to physics after his first year of study. He graduated in 1980 with a Bachelor of Science degree with College Honors and High Distinction in Physics and was also inducted into the Phi Kappa Phi National Honor Society. He remained at the University of Illinois for graduate school and developed an interest in fluid dynamics through some of his course work. He had always had an interest in the atmosphere and weather (particularly severe storms and hurricanes) and after some investigation, discovered that applied physics was a part of many graduate programs in the atmospheric sciences. He applied and was accepted into the Department of Geophysical Sciences at the University of Chicago in fall of 1982. The Department of Geophysical Sciences at Chicago was formed through the merger of the Departments of Meteorology and Geology. There were a number of landmark contributors to the science of the atmosphere and earth on the faculty at Chicago and among them were Prof. Tetsuya (Ted) Fujita, world-renowned tornado researcher and developer of the “F-scale” for measuring tornado intensity.
In addition to an interest in classical fluid mechanics as applied to the atmosphere and oceans, Dr. Zehnder was fascinated by applications of mathematics and in particular numerical analysis and settled on a theoretical/numerical study of the propagation of atmospheric fronts over mountains as his thesis topic under the supervision of Prof. Peter Bannon. The interaction of fronts with mountains was believed by many investigators to be responsible for the unusually high rates of formation of storms downwind of the Alps in the northern Mediterranean Sea. He was awarded a Ph.D. from the University of Chicago in Fall of 1986.
Dr. Zehnder’s first appointment was as a Visiting Scientist in the Laboratory for Atmospheres at NASA’s Goddard Space Flight Center in Greenbelt, MD under sponsorship of the U.S. National Research Council. NASA, through the Severe Storms Branch at Goddard, had participated in a multi-agency Genesis of Atlantic Lows (GALE) experiment, which focused on the rapidly developing and often severe “nor’easters” which affect the Atlantic seaboard in the winter. Dr. Zehnder applied the frontal model he’d developed for his Ph.D. to the interaction of fronts with low-level oceanic circulations as a proposed explanation for the rapid development of nor’easters.
From his earliest days at the U of I, Dr. Zehnder was interested in becoming a teacher and researcher at a major university. He began applying for faculty positions and in the spring of 1988 was offered a position as an assistant professor in the Department of Atmospheric Science at the University of Arizona in Tucson. The U of A, in addition to internationally recognized programs in a number of physical sciences, had one of the top applied mathematics programs in the country. Dr. Zehnder also held a position in the Department of Applied Mathematics at U of A.
While his early background was primarily as a theoretical geophysicist and applied mathematician, Dr. Zehnder developed expertise in synoptic meteorology and forecasting partly driven by an interest in the summer thunderstorms that occur during the North American Monsoon. When he arrived in Tucson in summer of 1988, he first became aware of the formation of hurricanes in the Eastern Pacific, which occur with a frequency of two to three times those in the Atlantic. By applying some of the concepts developed during his Ph.D. research, namely the organization of circulations through the impact of terrain, Dr. Zehnder developed a theory of tropical lee cyclogenesis that has been adopted by other researchers and operational forecasters in the U.S. and Mexico.
Shortly after arriving at U of A, Dr. Zehnder began to participate in observational field programs and this changed the focus of his research. The first of these experiments, SWAMP (Southwest Area Monsoon Project) was held in summer of 1990 and involved flights with a NOAA P-3 Orion, radiosonde measurements and a network of pilot balloons located in Mexico to study the structure of monsoon thunderstorms and the large-scale circulations that transport moisture into the region. A second experiment, TEXMEX (Tropical Cyclone Initiation Experiment) was held in 1991 off the west coast of Mexico. While the focus of TEXMEX was on the thermodynamics of developing tropical cyclones, aircraft data collected with the NOAA P-3 and NCAR Electra allowed testing and refinement of the theories on tropical lee cyclone formation.
A later experiment, EPIC-2001 (Eastern Pacific Investigations of Climate) was a multi-national and multi agency (NOAA, NSF, NASA and CICESE-Mexico) program dedicated to a study of the short and long term climate variability in tropical East Pacific that are driven in large part by the air-sea interactions in the region. While the focus of EPIC was on climate processes, Dr. Zehnder was part of a reconnaissance flight on the NOAA P-3 into the developing Hurricane Juliette.
Dr. Zehnder rose through the academic ranks at U of A, receiving tenure and a promotion to associate professor in 1994 and later a promotion to full professor in 2000. It was at that point that he left U of A and joined the faculty at Arizona State University in Tempe, AZ where he was appointed professor in the Department of Geography and held an affiliate appointment in Mathematics. ASU was in the process of expanding and there were a number of interdisciplinary research efforts on campus. One effort was a Center for Environmental Studies, which later became the Global Institute of Sustainability (GIOS).
Part of Dr. Zehnder’s duties at GIOS included serving as director of SCERP (Southwest Consortium for Environmental Research and Policy). SCERP was a consortium of 10 universities, 5 in the U.S. Southwest and 5 in Mexico that were funded by the U.S. EPA to investigate issues and provide solutions for problems related to the environment and ecosystems of the U.S.-Mexico border. While Dr. Zehnder’s background was primarily as a physical scientist, he gained valuable experience in areas of policy and problem oriented research through interaction with local and state governments, NGOs, tribal governments and other stake holders.
The scope of Dr. Zehnder’s research also expanded during this time, with a new focus on small-scale meteorological processes in urban areas and through collaborations with computer visualization specialists at PRISM (Partnership for Research in Spatial Modeling) at ASU. Much of his work on urban meteorology focused on aspects of the urban heat island and in particular, ways in which the increase residential areas contributes to changes in surface temperature in desert regions. His projections of changes to the daytime high and low temperatures in Phoenix with expansion of the urban area were featured as part of the opening of the ASU Decision Theater. His collaborations with the computer scientists at PRISM and later ASU ATIC (Advanced Technology Innovation Center) resulted in the development of an observational field program to study the onset and development of monsoon thunderstorms in southern Arizona.
This program was called the CuPIDO (Cumulus Photogrammetric, In-situ and Doppler Observations) and was a collaboration between ASU, UA, the University of Wyoming and the National Center for Atmospheric Research. The field phase of the project took place during the summer of 2006 in southern Arizona over the Santa Catalina Mountains near Tucson.
The idea behind CuPIDO was to begin observations prior to the onset of the convection and monitor the changes to the environment that occur through the action of the initial, shallow convection. Our central hypothesis was that the shallow convection moistens the profile and prevents the entrainment of dry environmental air, which limits the vertical development. Details of the CuPIDO experimental objectives, observing strategies and some results are discussed under the areas of expertise.
In Fall of 2006, Dr. Zehnder was recruited by the Creighton University Department of Atmospheric Sciences to serve as the chair of the department. He joined the faculty as a full professor and department chair in Fall of 2007 and helped to modernize the department computer facilities with the addition of a state-of-the-art meteorological data display laboratory and a multi-node linux cluster. He also revamped the undergraduate curriculum to meet the American Meteorological Society BS Degree recommendations, helped expand the graduate program and helped the department gain national recognition by becoming a UCAR member university.
In Spring of 2014, Dr. Zehnder left Creighton University and returned to Tempe to pursue research projects as an affiliate with Arizona State University
