Citation

Dr. Susanna Ebmeier is an exceptionally talented geophysicist, at the forefront of exploiting the revolution in satellite geodesy to advance our understanding of volcanic processes. She has a passion for using satellite observations to improve society’s response to volcanic hazards; her research has had a significant impact on scientific understanding and crisis management. Dr. Ebmeier’s primary geodetic tool is satellite radar interferometry (interferometric synthetic aperture radar, or InSAR). She has conducted groundbreaking research and developed innovative techniques that have probed the complex interactions between tectonics and volcanism and has pioneered the development and exploitation of global geodetic data sets to improve our understanding of magmatic processes. Creativity has been a hallmark of Dr. Ebmeier’s career. Early on she developed a new method capable of simultaneously determining the thickness/volume of volcanic deposits, alongside extrusion rates, and rates of lava subsidence. More recently she has focused on exploiting advances in signal processing methods, such as independent component analysis, for the extraction/analysis of volcanic signals. Dr. Ebmeier has consistently recognized the importance of working closely with scientists in volcano observatories. In Ecuador, her collaborations with the Instituto Geofísico (IG) have had a direct impact on society. During the 2014 seismic crisis at Chiles–Cerro Negro, IG increased the alert level to Orange (Level 3 of four levels) and evacuated approximately 3,500 families. Dr. Ebmeier responded rapidly to a request for assistance, using InSAR to identify the tectonic mechanism behind the earthquakes, a result critical to IG’s decision to lower the alert level, allowing evacuees to return home. Recently, Dr. Ebmeier led the development of COMET’s (Centre for Observation and Modelling of Earthquakes, Volcanoes and Tectonics) Volcano Deformation Portal, which provides near-real-time deformation monitoring data globally; she has supported scientists at observatories, as well as collaborators/stakeholders, to use this vital global resource. Dr. Ebmeier is increasingly involved in international efforts coordinating satellite observations at volcanoes, serving as cochair of the Committee on Earth Observation Satellites Volcano Demonstrator, where she has facilitated rapid no-cost access to expensive and/or inaccessible satellite data, including from commercial operators. She has further worked on ensuring that end users have the data products they need to support event response during crises—vital and unselfish service that benefits both science and society. Dr. Ebmeier is a young leader in the field of satellite geodesy, particularly applied to volcanic hazards assessment and mitigation. She is setting the agenda in the use of satellite geodesy in volcano observatories while remaining focused on solving fundamental scientific problems and developing new methods and interpretive tools. —Tim Wright, COMET, University of Leeds, Leeds, U.K.; Juliet Biggs, COMET, University of Bristol, Bristol, U.K.; and Mike Poland, Yellowstone Volcano Observatory, U.S. Geological Survey, Vancouver, Wash.

Response

I thank my nominators for their kind citation and for their thoughtfulness in putting me forward for the John Wahr Early Career Award. I feel honored to have been recognized by the AGU geodesy community, which has had a big influence on my science and academic outlook. I am very grateful for having been introduced to supportive members of the international volcano geodesy community early in my Ph.D. research. Since then, I have benefited greatly from their encouragement, advice, and example as research leaders. I was especially fortunate as a postdoctoral researcher in being supported to build connections with other researchers internationally, both at universities and in volcano observatories. This has shaped the path of my own research over the past decade, broadening my scientific interests and helping me keep a focus on the application of fundamental science to real-world problems. A great privilege of being a researcher is being able to keep learning and trying new things. I have recently had the pleasure of working with many postgraduate students and sharing in their exploration of new ideas. I would like to thank them, as well as my previous supervisors, current colleagues, and collaborators. I value all of our shared efforts, struggles, and inspiration. Finally, thank you to John Elliott for his insightful honesty, humor, and support in all aspects of life. —Susanna K. Ebmeier, University of Leeds, Leeds, U.K.

Citation

It is a great pleasure and honor to write this citation for Diego Melgar, winner of the 2022 John Wahr Early Career Award. Diego Melgar is a prolific early-career scientist whose research is notably deep and broad, pushing the interdisciplinary boundaries between geodesy and seismology. Indeed, he is a pioneer of the nascent field of seismogeodesy. His research is transformative, with broad impact by introducing real-time geodesy and rapid modeling of seismogeodetic data to the operational world of earthquake and tsunami warning. Diego is both an accomplished geodesist and seismologist, with a focus on large earthquakes and how they develop in time, and tsunami modeling for early warning. His publication record is simply stellar for someone at such an early-career stage. With only 8 years since his Ph.D. in 2014, Diego has an astounding record of over 80 peer-reviewed journal publications, many of which have been cited over 100 times, with a total of over 3,700 citations. His body of papers demonstrates consistent innovation, following a coherent theme of attempting to understand the rupture process for large earthquakes. In addition to scientific impact, his research is having a profound impact on meeting societal needs, as his applied research relates to tsunami warning systems. Diego has taken this avenue of applied research to a much higher level where the research is transformative; that is, it is now at the application stage. Diego’s contributions are significant, with a focus on improving the modeling of tsunami genesis. I would also like to highlight Diego’s extensive mentoring of students and postdocs and his service to the scientific community. Notably, he was selected to serve on the National Academy of Sciences (NAS) Committee on Solid Earth Geophysics. Importantly, NAS committees have a significant impact on the future of the field. Also notably, Diego serves on the NOAA Tsunami Science Technical Advisory Panel, which helps his science become transformative and practical for society. In addition, he has served on numerous committees for important scientific consortia such as UNAVCO (geodesy), Incorporated Research Institutions for Seismology (seismology), and the International Association of Geodesy Global Geodetic Observing System. In conclusion, Diego Melgar is leading the way on better models for earthquakes and tsunamis that can be applied to early warning and have societal impact. He has a stellar record for someone at such an early-career stage and is a strong role model for students and other early-career scientists. —Geoffrey Blewitt, University of Nevada, Reno

Response

It has been a great pleasure to be part of a thriving geodetic community during a time of significant technological and scientific innovation. The proliferation of real-time networks, advances in data science, and the occurrence of numerous catastrophic earthquakes have made the past decade a moment of great historical relevance for research into large earthquakes and their physics and hazards, and for real-time response systems. First and foremost, I am grateful to my partner and fellow geophysicist Valerie Sahakian for her companionship and for endless discussions about the mysteries of life, our planet and its people, and the universe at large. I am indebted to all my teachers and mentors who have selflessly given their time to my training and education: Xyoli Perez-Campos, who imbued in me a love of Earth science, Yehuda Bock and the group at the Scripps Orbit and Permanent Array Center (SOPAC) for teaching me about real-time Global Navigation Satellite Systems (GNSS), and Richard Allen and the Berkeley Seismology Lab where I learned all about early warning systems. I am especially grateful to my colleagues, the postdocs, the graduate students, and the community at the University of Oregon where I have found a wonderful place to thrive as a scientist, one that values the human aspects of the scientific endeavor as much as the technical ones. My love for Earth science exists because our planet is still a source of awe and of myriad open questions. Deepening our understanding of them can bring one great intellectual joy, but it also allows us to harness the new knowledge for the social good. Combining those two facets of science has always been my fundamental motivation. While Earth science has a long road ahead to fulfill its promise of becoming just and equitable, I am heartened that we live in a time of vigorous debate surrounding the nature of our shared societal values as a scientific community of practice. Our fields and research are meaningless without people. Science ought to be an endeavor shared by a diverse community of individuals all problem-solving, from distinct perspectives, together for a bright future. Here, geodesy has a fundamental role to play, and so I am honored to receive the John Wahr Early Career Award. It strengthens and motivates me to keep pushing forward. —Diego Melgar Moctezuma, University of Oregon, Eugene

Raphaël Grandin received the 2019 John Wahr Early Career Award at AGU’s Fall Meeting 2019, held 9–13 December in San Francisco, Calif. The award is given “in recognition of major advances in geodesy.”

Citation

Raphaël Grandin obtained a master of science degree in executive engineering at École des Mines de Paris and a Ph.D. at Institut de Physique du Globe de Paris (IPGP). He held a position of teaching assistant at University of Paris, was a postdoctoral fellow at École Normale Supérieure de Paris, and is now an associate professor at University of Paris and IPGP.

Raphaël studied a variety of geophysical problems related to seismology, rifting and magmatic processes, and earthquake source models using space-based geodesy. It is with innovative advances in the methods and applications of interferometric synthetic aperture radar (InSAR) that his scientific contributions stand out.

His early work on the Ethiopian rifting episode of 2005–2009 provided an unprecedented account of the entire sequence of events, placing constraints on tectonic stress, magmatic pressure, and the time-dependent migration of magma between deep and shallow reservoirs. In the Himalaya, he used innovative data correction methods to extract the uplift velocity profile across the range, highlighting the stepwise migration of crustal ramps to the mountain front.

What characterizes Raphaël’s work is a combination of fine observations and the development of innovative physical interpretations of the processes behind those observations. This is exemplified in the study of recent earthquakes, from both tectonic (Nepal, 2015; Chile, 2012) and man-made (Oklahoma, 2016) origins.

Raphaël is also a dedicated mentor and teacher. He contributed to the development of community InSAR software and serves as scientific advisor for the Centre National de la Recherche Scientifique (CNRS) Solid Earth Data Center in France. He received citations for excellence in refereeing from the editors of two AGU journals in 2013 and 2014 and of Earth, Planets and Space in 2015.

We are thrilled to see Raphaël’s achievements recognized by the 2019 John Wahr Early Career Award.

—Marie-Pierre Doin, Institut des Sciences de la Terre, Université Grenoble Alpes, Grenoble, France; and Gilles Peltzer, University of California, Los Angeles

Response

Receiving the 2019 John Wahr Early Career Award is a great honor for me. I knew nearly nothing about geology until the age of 20, as I was entering the French grandes écoles system. Just as I was about to embrace an engineering career in industry, joining the Institut de Physique du Globe de Paris as an intern totally changed my perspectives about scientific research. I owe a lot to my professor, Pascal Podvin, and to my mentor, Geoffrey C. P. King, who encouraged me to pursue this direction, recognizing that I had suddenly become passionate about earthquakes and volcanoes.

This nomination also rewards collaborative efforts to expand the development and application of InSAR. I am extremely grateful to Jean-Bernard de Chabalier and Anne Socquet for introducing me to InSAR in 2007. I have been lucky to benefit from data generously provided by space agencies (in particular, the European Space Agency) and from open-source software developed by pioneers in the field (especially ROI_PAC and its expansion through NSBAS). I am thankful to Marie-Pierre Doin and Gilles Peltzer for sharing their deep understanding of InSAR ever since.

Space geodesy is about to enter a new stage of development, with the launch of next-generation SAR systems and swarms of small SAR satellites. The free and open data policy adopted by international space agencies will continue to boost the development of nascent research directions. Easy access to imagery is equally important to facilitate collaboration with local authorities in charge of volcano surveillance and earthquake hazard mitigation and, eventually, to benefit threatened populations.

Just as others did for me, I wish to be able to take my share in supporting and inspiring the next generation of young researchers, to make the best of these new opportunities.

—Raphaël Grandin, Institut de Physique du Globe de Paris, Université de Paris, Paris, France

Juliet Biggs will receive the 2017 Geodesy Section Award at the 2017 American Geophysical Union Fall Meeting, to be held 11–15 December in New Orleans, La. The award is given “in recognition of major advances in geodesy.”

Citation

Juliet Biggs has made outstanding contributions to the field of satellite geodesy for understanding both active volcanism and faulting.

As a student, Juliet developed an innovative method for making interferometric synthetic aperture radar (InSAR) observations where the ground cover was nonideal. This allowed her to make unique observations of how strain was distributed in space and time before and after the 2002 Denali earthquake in Alaska.

During her postdoc, Juliet shifted her main focus to volcanic processes. Through systematic surveying of the world’s volcanoes, she discovered that several volcanoes in Kenya and Ethiopia, previously thought to be dormant, were actually undergoing episodes of deformation.

Juliet went on to examine the link between eruption and deformation from a global compilation of volcanoes, showing that very few eruptions occur without observable deformation. This work won her the Lloyd’s Science of Risk Prize in 2014 and led to the formation of the Global Deformation Database Task Force.

Juliet’s contributions to the field of geodesy go beyond measuring deformation with InSAR. She has developed methods for measuring rapid topographic changes at erupting volcanoes using radar, and methods to integrate a wide variety of other geodetic observations. She also recognizes that major advances require input from different disciplines and is currently co-leading a major project to understand volcanism in the Main Ethiopian Rift through the integration of geophysical, geological, and geochemical observations.

Juliet’s work has been, and continues to be, extremely influential internationally. Her research pushes the boundaries of our understanding of volcanic systems and delivers real-world benefits. I am thrilled that her achievements are being recognized with the 2017 AGU Geodesy Section Award.

—Andy Hooper, University of Leeds, Leeds, U.K.

Response

Many of the previous AGU Geodesy Section Award winners have been role models for me personally, and seeing my name among them is truly humbling. I am honored to receive this award and am especially grateful to Andy Hooper for his citation.

It is a privilege to work in a field that has applications across a broad spectrum of the Earth sciences yet retains its own identity and sense of society. The AGU Geodesy community has nurtured my career in many ways over the years; from invaluable feedback at poster sessions, to a student award in 2005, and to my first invited talk in 2008. From my early work on faults in the United States, to current projects on volcanoes in Africa and Latin America, geodesy has given me the opportunity to explore the world, a highlight of which is collaborating with scientists from a wide range of backgrounds and specialties.

In reality, this award is not an individual honor but a tribute to a number of colleagues, supervisors, and students who have inspired, advised, and supported me over the years. In particular, Tim Wright and Barry Parsons set me on a path of scientific curiosity, rigor, and integrity that I endeavor to follow to this day. At an early stage, Bramley Murton and Mark Simons somehow found time in their busy academic schedules to provide summer undergraduate research opportunities and opened my eyes to a whole new field. These days, I am enormously proud to work alongside some inspirational scientists—students, postdocs, and colleagues—who each bring their individual ideas, challenges, and rewards and ensure that no day is ever dull. My thanks go to all of you and to the countless others whose hard work behind the scenes makes all this possible.

—Juliet Biggs, University of Bristol, Bristol, U.K.

Emma M. Hill will receive the 2016 Geodesy Section Award at the 2016 American Geophysical Union Fall Meeting, to be held 12–16 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy.

Citation

Throughout her career, Emma Hill has endeavored to develop the breadth of research interests and geodetic expertise that are now her hallmark, addressing an array of multidisciplinary problems that includes sea level, glacial isostatic adjustment, atmospheric turbulence, hydrology, GNSS accuracy, and tectonics.
As a student and postdoc, Emma focused on GNSS studies of the Basin and Range. This work included the tectonics of the region and also characterization of atmospheric turbulence. She also has the distinction of publishing a GPS time series having an RMS residual of 50 microns! Emma later pioneered Bayesian combination of data from GRACE, tide gauges, and GNSS that enabled inversion for Fennoscandian glacial isostatic adjustment without estimation of parameters from a simplified Earth model.

Her recent research has focused on Southeast Asia, studying deformation associated with the Sunda megathrust using GNSS, InSAR, and coral uplift histories. These studies have led to an improved understanding of the tectonics of this region, and to discovery of a 15-year-long slow-slip event.

Emma has a strong commitment to the Earth science community. She has served as judge for the Outstanding Student Paper Award and organized a student poster competition for EarthScope. She served as Chair of the UNAVCO E&O Advisory Committee. Her activities in AGU governance include the AGU International Participation Committee and AGU Council. She is currently serving as an associate editor for Journal of Geophysical Research.

Emma is a devoted mentor and has attracted an outstanding assembly of students and postdocs to her group. She is highly valued as a mentor, group leader, and as a collaborator.

We are very pleased that the AGU Geodesy section has recognized Emma’s scientific achievements and leadership with the 2016 Geodesy Award.

—Kristine M. Larson, University of Colorado, Boulder; and James L. Davis, Lamont-Doherty Earth Observatory of Columbia University, Palisades, N.Y.

Response

I feel honored to receive this award, and am grateful to Jim and Kristine for their kind citation. The award is particularly special to me because the AGU Geodesy section has long felt like my academic family; I have always been grateful for the spirit of collaboration and friendship in our community.

I feel lucky to work in a field where we connect with many disciplines in Earth science, and one in which our research is directly applicable to the significant challenges facing our communities and environment. This has been particularly clear to me since working in Southeast Asia, where some of the highest population densities on Earth are faced with tectonic, volcanic, and climate hazards for which we are answering first-order questions using geodetic data.

To maximize scientific impact, we must build capacity in the areas in which we work. It has been deeply rewarding to work with and train young scientists from Southeast Asia; I am grateful for their hospitality, enthusiasm, and introductions to tasty food.

It is impossible to individually thank everyone who has helped me along the way, but I would here like to thank Geoff Blewitt and Jim Davis for their mentorship and encouragement; Kerry Sieh and Paul Tapponnier for giving me so many exciting opportunities in Singapore; my students and postdocs for making every day at work delightful—Lujia Feng, Eric Lindsey, Louisa Tsang, Qiu Qiang, Rino Salman, Paul Morgan, Rishav Mallick, and Dongju Peng—and a host of colleagues and collaborators who have shared their time and wisdom—Mark Tamisiea, Pedro Elosegui, Aron Meltzner, and Sylvain Barbot to name just a few. I would also like to give heartfelt thanks to all the generous souls who unselfishly collect data, maintain networks, release processing code, and thus make our science possible.

—Emma M. Hill, Earth Observatory of Singapore and Asian School of the Environment, Nanyang Technological University, Singapore

Matthew Pritchard will receive the 2015 Geodesy Section Award at the 2015 American Geophysical Union Fall Meeting, to be held 14–18 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy.

Citation

Matt Pritchard is presented with the 2015 Geodesy Section Award for his transcendent work in volcano and earthquake science and selfless support of the community. Matt was among the first to use interferometric synthetic aperture radar (InSAR) to examine entire volcanic arcs instead of individual volcanoes. This broader approach led to the recognition of a number of deforming volcanoes that were previously unknown, stimulating several follow-on studies, and has elucidated linkages between arc volcanism and large earthquakes. Matt’s efforts also proved the viability of broad monitoring of volcanic arcs from space, establishing the basis for international efforts to develop a global volcano monitoring strategy. In addition to volcanology, Matt has lent his considerable expertise to seismology, tectonics, planetary geology, glaciology, and climate change. Although InSAR remains Matt’s primary observational tool, he has shown exceptional vision by combining InSAR with other remote sensing, seismic, and geologic data to attain a more synergistic view of volcanic and earthquake processes.

Although Matt’s research alone is ample justification for the Geodesy Section Award, his record is impressively supported by a strong commitment to the community through his teaching excellence and service on numerous committees and initiatives, including WInSAR (Western North America Interferometric Synthetic Aperture Radar Consortium), UNAVCO (University NAVSTAR Consortium), NISAR (NASA-ISRO SAR Mission), GeoPRISMS (Geodynamic Processes at Rifting and Subducting Margins), the Global Volcano Model, and the CEOS (Committee on Earth Observation Satellites) Volcano Pilot. In each of these areas Matt has promoted data sharing and collaboration as means to maximize science return. Matt is also an exceptional colleague, generous with his time and expertise, providing assistance to international scientists and volcano observatories in the use of InSAR to respond to volcano and earthquake crises.

The field of geodesy is better for having Matt as a colleague. Not only has his research moved several fields forward, Matt has also advanced the community through his unselfish service. We are pleased that Matt Pritchard’s dedication and research excellence are being recognized with the 2015 Geodesy Section Award.

—Michael P. Poland, Cascades Volcano Observatory, U.S. Geological Survey, Vancouver, Wash.; and Paul R. Lundgren, Jet Propulsion Laboratory, Pasadena, Calif.

Response

I am humbled and honored by the kind citation. Although I find that the award process is inadequate—there are so many deserving who are overlooked—I appreciate everyone who helped with my nomination.

This is an exciting time in geodesy. There is an explosion of new techniques and satellite missions that allow us to tackle important scientific and societal problems, but I only became aware of this field once I arrived in graduate school. On the basis of this admittedly limited evidence, I suggest that we have to work harder as a community to communicate the opportunities to younger students—in particular at the middle and high school levels. My interest in geology and planetary science was nurtured during those grades by numerous volunteers who aided and judged science fair and 4-H projects, gave public lectures, and answered my questions about careers in the field. In particular, I want to thank Robert H. Brown of the University of Arizona—he answered many questions from a high school student thousands of miles away that resulted in a Westinghouse Science Talent Search project and set me on the path to graduate school at the California Institute of Technology (Caltech). Whenever I feel too busy to respond to help random students, I try to remember his example.

One great perk of being a geodesist is the supportive community of scientists. I thank my students, postdocs, mentors, advisers, and collaborators for teaching me so many interesting things and making this such a fun career. Of course, there are always bumps in the road, and I owe a lot to my wife and collaborator on projects big and small, who makes the journey worth it, Rowena Lohman, the 2013 recipient of this award.

—Matthew E. Pritchard, Cornell University, Ithaca, N.Y.

Citation

Rowena B. Lohman received the 2013 Geodesy Section Award at the 2013 AGU Fall Meeting, held 9–13 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation Rowena received her Ph.D. from the California Institute of Technology under the direction of Mark Simons, one of the pioneers in the relatively new field of satellite deformation imaging. In her own work, she has broken new ground by exploring the boundaries between geodesy and seismology. She has shown how the apparent disagreement between these two data types can provide novel insight into subsurface processes. For example, a discrepancy in seismic moment may indicate aseismic slip. Discrepancies in event locations can ferret out seismic mislocation biases with resulting improvement in global velocity models. Another focus of Rowena’s activities has been the development of more rigorous techniques for placing geodetic constraints on the distribution of deformation sources (e.g., coseismic slip and volcanic inflation). Such techniques are crucial to exploiting the richness of interferometric synthetic aperture radar (InSAR) data. In addition to the issue of model regularization, Rowena has undertaken a rigorous consideration of the error budget in InSAR data, addressing the use of both the variances and, more importantly, the covariances intrinsic to the data. Rowena is certainly not reluctant to venture into new realms, as shown by her exploration of the potential of InSAR to address problems as diverse as the distribution of vegetation canopy height, monitoring of subsurface carbon dioxide sequestration, and scrutiny of hydraulic fracking. Rowena’s service to the geodetic community is as noteworthy as her research contributions. She has been remarkably generous with her time and effort, spending a great deal of energy on the activities of numerous organizations (UNAVCO, Western North American InSAR (WInSAR), Southern California Earthquake Center (SCEC), Earthscope, associate editor for Journal of Geophysical Research, and the initial science study group for the current L band synthetic aperture radar formulation). The geodesy award is intended to recognize young scientists for important advances “in geodetic science, technology, applications, observations, or theory.” By any measure, professional or personal, Rowena is an exemplary recipient of the AGU Geodesy Section Award. —LARRY D. BROWN, Cornell University, Ithaca, N.Y.

Response

I am very honored to be this year’s recipient of the AGU Geodesy Section Award. I was fortunate to begin my academic career at a time when there was an explosion of new data types and computational resources. I have been very pleased to watch this trend continue, with the ongoing support of new InSAR missions worldwide and renewed interest in the democratization of access to this data. When I began my graduate research, it still took several months to order individual SAR acquisitions; the advent of community-driven data archives such as WInSAR, GeoEarthscope, and the Supersites and their support by NASA, the National Science Foundation, the U.S. Geological Survey, and their international partners has simply revolutionized the field and has facilitated an explosion of techniques for ingesting InSAR time series and the extraction of progressively smaller signals from the data sets. This improved ease of access and the processing tutorials hosted by groups such as UNAVCO will hopefully encourage participation in the InSAR community by new users. We live in a time when we are bearing witness to rapid changes in land use on an unprecedented scale, including increases in resource extraction worldwide and growth of populations exposed to hazards (including landslides, volcanoes, earthquakes, and sea level rise). Geodesy will play a key role in the monitoring of these changes and can guide society’s response into the most fruitful avenues. I benefitted greatly from the guidance of my graduate thesis advisor, Mark Simons, who encouraged me to think both about tectonic problems and the challenges (and opportunities) facing society today. I also thank my postdoctoral sponsors, including Jeff McGuire, Paul Lundgren, and Eric Fielding. My sincere hope is that I will have the opportunity to repay their efforts by supporting other early-career researchers in my turn. —ROWENA B. LOHMAN, Cornell University, Ithaca, N.Y.

Citation

Matt A. King received the 2012 Geodesy Section Award at the 2012 AGU Fall Meeting, held 3–7 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation We have known Matt for more than a decade, since shortly after he completed his Ph.D. research at the University of Tasmania, Australia, in 2001 and relocated to Newcastle University, U.K. His work has concerned geodetic applications in solid Earth and cryospheric studies, with his pioneering use of precise Global Navigation Satellite Systems (GNSS) in glaciology especially notable. His research has involved novel and fruitful studies to mitigate a range of GNSS error phenomena, particularly subdaily errors related to tides and multipath and their biasing effects on longer-term coordinate time series. From these technical insights, Matt and collaborating glaciologists have made groundbreaking discoveries of the nonlinear behavior of glaciers and ice streams. His current research efforts focus on constraining Antarctic Holocene deglaciation and Earth rheology through measurements of glacial isostatic adjustment (GIA), with an end goal of improving our understanding of the present-day ice mass balance. Matt is a tireless collaborator and has been unstinting in his efforts on behalf of the community and with training the next generation of “cryogeodesists” by leading workshops at UNAVCO and in Europe and by supporting students. He has also been a strong mentor to other early-stage researchers at Newcastle and elsewhere. His community leadership includes serving AGU by chairing the Fall AGU Geodesy Program Committee (2009–2010) and leading Newcastle’s hosting of the International GNSS Service Workshop 2010. He proposed and chaired COST Action ES0701 (2008–2012), a research network of around 80 European geodesists and modelers of GIA, and, similarly, the Detection of Offsets in GPS community Experiment (DOGEx). He is now leading the International Association of Geodesy (IAG) subcommission on cryospheric deformation. His earlier research has been recognized with a Philip Leverhulme Prize and several personal research fellowships, and we are delighted to see him receive this award—we can think of no better recipient for 2012. —PETER CLARKE, School of Civil Engineering and Geosciences, Newcastle University, Newcastle, UK; and SRIDHAR ANANDAKRISHNAN, Department of Geosciences, Pennsylvania State University, University Park

Response

It is a great honor to receive the AGU section award. After a fairly unpromising start to my undergraduate studies at the University of Tasmania I gained an interest in geodesy under the instruction of Richard Coleman, with whom I later completed a Ph.D. and to whom I give significant credit for this award. My work with Richard involved applying geodetic techniques to the study of the dynamics of an Antarctic ice shelf. Some of our new GPS data exhibited unexpected periodic variations in the horizontal coordinate components. As a group we identified that some of these signals were entirely spurious due to incorrect GPS processing strategies conventionally applied in glaciological studies and then developed improved analysis strategies. Around the time I finished my Ph.D., I was blessed to be connected to leading glaciologists investigating similar phenomena—notably Bob Bindschadler and Sridhar Anandakrishnan—by a former University of Tasmania (UTAS) colleague, Helen Fricker. Those connections were extremely fruitful and led to further rewarding collaborations with other glaciologists in the United States, the United Kingdom, and the rest of Europe. My time within the geodesy group at Newcastle University has been especially rewarding. They took a chance on appointing a young postdoc from the other side of the world, and I’d like to thank them for that and then giving me the opportunity to pursue my own research interests as well as learn from, and collaborate with, them. More recently, and not far from Newcastle at Durham University, I’ve worked with another set of fantastic collaborators, namely, Mike Bentley and Pippa Whitehouse, on the problem of Antarctic GIA as it pertains to the Gravity Recovery and Climate Experiment (GRACE). It’s been an honor to work with such good scientists while having such fun times. But most of all, I’d like to thank my wife, Julia, and our children for supporting me. —MATT A. KING, School of Geography and Environmental Studies, University of Tasmania, Hobart, Tasmania, Australia

Citation

Sean Claude Swenson received the 2011 Geodesy Section Award at the 2011 AGU Fall Meeting, held 5–9 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation We are delighted to see Sean Swenson receive the 2011 Geodesy Section Award. Sean is a superb young scientist who, through his ideas and publications, has had a significant impact on the Gravity Recovery and Climate Experiment (GRACE) satellite mission. He has fundamentally advanced the way people analyze and interpret GRACE data. His work has involved both the development of analysis techniques and the application of those techniques to geophysical problems. Sean’s contributions to GRACE analysis include the development of methods for transforming the GRACE spherical harmonic gravity coefficients into regional estimates of surface mass and his discovery of a way to clean up much of the short-scale noise in the publicly available GRACE data. Both of these techniques are straightforward to implement and are now routinely applied by users everywhere. But Sean’s work extends well beyond the development of analysis methods. His reason for working on analysis procedures was his desire to extract small, localized signals from GRACE data to study geophysical problems. He has used GRACE to study such varied things as the mixed-layer depth of the Caspian Sea; the vertical and horizontal scales of soil moisture in various regions of North America; the source of lake level fluctuations in Lake Victoria; regional-​scale fluxes of atmospheric water vapor; and the reliability of the large-scale, high-latitude winter precipitation data sets routinely used to force climate models. Sean’s work has been extremely influential, especially for somebody so early in his career. He is an innovative, rigorous, enthusiastic, and highly unassuming young scientist who is an outstanding choice for the Geodesy Section Award. —John Wahr, Department of Physics and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder — Mark Tamisiea, National Oceanography Centre, Liverpool, UK

Response

I am honored to receive the AGU Geodesy Section Award; it is certainly a pleasant surprise. My contributions to geodesy derive from my involvement with the Gravity Recovery and Climate Experiment (GRACE), which has been to me and many others a tremendous source of information and opportunity. The scope of geophysical phenomena that can be addressed by GRACE is extensive, including glacial ice loss, land-ocean water exchange, groundwater depletion, and surface water management to name but a few. For the past 10 or more years the GRACE mission has enabled me to explore a wide variety of topics in the Earth sciences, from spectral analysis and filtering techniques to hydrological modeling. While GRACE has already helped quantify the role of terrestrial water storage in the water cycle, many questions remain. Some will be answered by longer data records, some by ­higher-​­accuracy future GRACE-type missions, and some by novel applications of current data. I am eager to see what new insights the GRACE community will obtain in the future, and I hope to remain an active participant in those endeavors. We are all born ignorant and spend the rest of our lives hopefully becoming less so. I would like to thank those who have helped my slow progress down that path. There are many colleagues in the geodetic community and collaborators in other fields whose interactions have benefited me, but I would especially like to thank Mark Tamisiea and Isabella Velicogna for their constant encouragement and, most of all, John Wahr, from whom I continue to learn what it means to be a good scientist. —Sean Claude Swenson, National Center for Atmospheric Research, Boulder, Colo.

Citation

Corné Kreemer received the 2010 Geodesy Section Award at the 2010 AGU Fall Meeting, held 13–17 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation It is a great pleasure for us to cite Corné Kreemer for the 2010 Geodesy Section Award, which is awarded to early to middle—career scientists to recognize major advances in geodesy. Both of us have been very fortunate to have worked with Corné during this first phase of his career, starting with Bill Holt at State University of New York at Stony Brook and now with Geoff Blewitt at University of Nevada, Reno. Although the official citation given at the 2010 AGU Fall Meeting was necessarily very short to fit on the plaque, we would like to take this opportunity to provide a more detailed citation that reflects the diversity and depth of Corné's contributions: In recognition of major innovations, discoveries, and scientific contributions in geodesy and its application to tectonophysics, as exemplified by (1) a novel technique to determine absolute plate motions independent of hot spots by joint inversion of space geodetic data and seismic shear wave splitting orientations; (2) the first empirical determination of present-day motion and deformation of the Colorado Plateau; (3) the discovery of an active shear zone connecting the Wasatch Front to the Eastern California Shear Zone; and (4) major advances in the development of the International Lithosphere Project's Global Strain Rate Map. The number of his publications in high-quality journals is staggering for someone still early in his career. Having obtained his Ph.D. as recently as 2001, he has 39 peer-reviewed publications, 30 of which are in highly regarded peer-reviewed journals, including Geology, Journal of Geophysical Research, Geophysical Research Letters, Tectonophysics, Geophysical Journal International, Earth and Planetary Science Letters,Journal of Geodesy, and Seismological Research Letters. Corné Kreemer is a rising star in geodesy. With his stellar trajectory, the best part about this is that we know for sure that we are in for some pleasant surprises as he continues to find new ways to apply geodesy to tease the data and reveal more about our interesting planet. —Geoffrey Blewitt, University of Nevada, Reno; and WILLIAM HOLT, State University of New York at Stony Brook

Response

I am honored to receive this award, and I feel deeply indebted to AGU, the Geodesy section, and those involved in the nominating process who bestowed on me this honor. By good fortune, I embarked on a career in geophysics at the same time that GPS began to be used to measure plate motion and crustal deformation. Before I knew about GPS, I enjoyed a solid background in geophysics at Utrecht University, Netherlands. For my master's thesis I began to use the new modeling tools developed by John Haines and Bill Holt. I started my Ph.D. project with Bill, utilizing the rapidly expanding database of GPS velocity measurements and John's clever rewrite of the software to model strain rates worldwide. By doing things globally I was able to venture into directions that still fascinate me: earthquake statistics and absolute plate motions. It also got me in touch with Geoff Blewitt and his effort to create global GPS solutions. Working with Xavier Le Pichon and colleagues in France provided a much needed chance to combine data from GPS, seismicity, and geology and to place models of surface deformation into the context of tectonic evolution, deeper deformation, and the driving forces. At the University of Nevada, Reno (UNR), I found an exceptional group in which to broaden my skills and interests. Geoff's ability to create GPS time series for thousands of stations around the world provides a chance to revolutionize our understanding of earthquakes, plate tectonics, and mass movement. My particular excitement comes from probing the subtleties in time-variable strain, the deformation in slowly deforming areas, and the role of the processes that lie below. I wish to thank all whom I have had the honor to work with, the geodetic community for sharing data, my UNR colleagues for their support, and my wife and parents for their love and encouragement. —Corné Kreemer, University of Nevada, Reno

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Shin-Chan Han received the AGU 2009 Geodesy Section Award at the 2009 AGU Fall Meeting, held 14–18 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation It gives us great pleasure to see Shin-Chan Han receive AGU's 2009 Geodesy Section Award, presented to a young scientist for major advances in the field of geodesy. Shin-Chan burst upon the geodetic scene just before the launch of the Gravity Recovery and Climate Experiment (GRACE) satellites, and the timing could not have been more propitious—both for Shin-Chan and for the GRACE project. His doctoral thesis at Ohio State University dealt with efficient methods for determining gravity from satellite-to-satellite tracking data, of the sort GRACE was soon providing. Soon thereafter a remarkable series of papers began to appear, as Shin-Chan exploited the new time-variable gravity measurements for applications ranging from surface water hydrology, to earthquake deformation, to ocean tides. All of these used new and highly original methods for extracting signals from the basic satellite tracking data. His analysis of the gravity changes associated with the great 2004 Sumatra earthquake was a revelation to many, for it emphasized the power of satellite gravity data to complement seismology, for example, by constraining the long-wavelength viscoelastic relaxation and subsequent stress redistribution. We are impressed by Shin-Chan's ability, at his young age, to reach out across disciplines, to establish new and productive collaborations, and to understand what important problems are ripe for advancement. He has, for example, recently applied some of his new techniques to improving our knowledge of the Moon's gravity field. We are sure that Shin-Chan has many similar advances ahead of him and is therefore most deserving of this award. —Richard D. Ray, NASA Goddard Space Flight Center, Greenbelt, Md. —Christopher Jekeli, Ohio State University, Columbus

Response

Thank you, Richard and Chris, for your generous remarks. I am thrilled and honored to accept this award from the Geodesy section of AGU. I started to study geodetic science simply due to my interest in the Global Positioning System (GPS) right after I graduated from an Earth science department in South Korea—at that time, geodesy was very esoteric to me. While studying at the geodetic science department at Ohio State University, I soon learned the intricate and fascinating relationship between geometric and gravimetric aspects of geodesy. I was fortunate to have the opportunity to study geodesy and to participate in the GRACE science team. The work with GRACE for applications to climate, hydrology, oceanography, tectonics, and solid Earth is not only an important interdisciplinary research agenda that geodesy can uniquely address, but it is also simply a lot of fun. During my study and work I have also been very fortunate to meet people who encourage my work and are very supportive in many ways. I would like to thank colleagues I meet every day in Greenbelt, Md., including Dave Rowlands, Richard Ray, Frank Lemoine, Scott Luthcke, and Jeanne Sauber. I would also like to acknowledge the folks at Ohio State University, Christopher Jekeli, C. K. Shum, Mike Bevis, and Doug Alsdorf. I am delighted to share this honor with them. They are the ones who give me confidence and enjoyment in my research on geodesy. This award indeed invigorates me. I hope this event is expanded so that many other young geodetic scientists are stimulated and recognized. Finally, I thank my family and wife, In-Young, for being with me. I appreciate her listening to me ramble about satellites and gravity. I always thank God for being patient with me. —Shin-Chan Han, NASA Goddard Space Flight Center, Greenbelt, Md., and University of Maryland Baltimore County, Baltimore

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Don P. Chambers received the 2008 Geodesy Section Award at the 2008 AGU Fall Meeting Honors Ceremony, held 17 December in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation Don P. Chambers is a highly respected member of the satellite altimetry, satellite gravity, and oceanographic communities and has made many original contributions on the El Niño phenomenon, ocean heat storage, ocean circulation, and long-term sea level change. Since receiving his Ph.D. in aerospace engineering from the University of Texas at Austin, in 1996, he has worked there as a research scientist at the Center for Space Research. He has published on a wide array of topics related to geodesy, oceanography, hydrology, and glaciology. Don can more than hold his own in scientific conversations with leaders in any of these fields, which is really important in the field of geodesy today, because it has changed so much over the past decade. One of the reasons I felt so strongly that Don should receive this award is because I view him as one of the “new breed” of geodesists who works on multidisciplinary problems using all different types of satellite and in situ measurements. Don's work on data from the Gravity Recovery and Climate Experiment (GRACE) mission exemplifies this—he has moved beyond the narrow geodetic interests of geopotential coefficients and orbit determination to become an expert on the applications of these data to critical problems in Earth system science. He has a keen mind for science but also possesses the geodetic and data analysis skills to extract the science from complex geodetic data sets. He is a member of the NASA science teams for the Jason 1, Jason 2, and GRACE missions—a significant accomplishment. One of the reasons for this success is Don's innovative approach to problem solving; he always seems to have a clever solution for the complex problems we face in geodesy today. This, coupled with his ability to understand multiple scientific disciplines, has allowed him to make many important contributions to our field. Don has quickly developed into one of the leaders of the “new” geodesy era we are currently experiencing as technologies such as Global Positioning System, satellite gravity, and satellite altimetry have transformed the field. As Don embarks on a new academic career at the University of South Florida, I am confident he will continue to make important advances in our field. —R. Steven Nerem, Department of Aerospace Engineering Sciences and Colorado Center for Astrodynamics Research, University of Colorado, Boulder

Response

I am honored to receive the Geodesy Section Award. When I started my graduate studies at the University of Texas Center for Space Research (CSR) under Byron Tapley, I did not have any appreciation of what geodesy was. One of my undergraduate friends told me that CSR “measured the Earth's gravity,” which did not seem all that exciting at the time. I figured I would accept the graduate research assistant position, do the work asked of me, and study what I was really interested in: satellite missions to asteroids. One look at my publications will show that never happened. Instead, I have worked on precise orbit determination, determination of the Earth's gravity, sea level change, ocean circulation, ocean heat storage, Rossby wave dynamics, El Niño, ocean bottom pressure, and the global water cycle. I have learned that geodesy is a lot more than just measuring gravity. I feel lucky now that I was offered that first position and that I accepted it. It gave me the unique opportunity to be involved early in two groundbreaking satellite geodesy missions: TOPEX/POSEIDON and the Gravity Recovery and Climate Experiment. Working with the early data from both of these missions has given me keen insight into the mixture of engineering and science necessary to measure sea level and gravity from space. Geodesy is perhaps the most interdisciplinary of all the sciences, and I am fortunate to have worked with numerous colleagues over the years. There are too many to name, but I would like especially to thank Steve Nerem for our long-term partnership on measuring sea level change, and Bob Stewart and Victor Zlotnicki for early support and guidance in my efforts to use geodetic measurements and techniques to study the ocean. —Don P. Chambers, University of Texas at Austin

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Mark Tamisiea received the Geodesy Section Award at the 2007 AGU Fall Meeting in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation Mark Tamisiea has made significant and original advances in solid Earth geophysics and has begun to be an important leader in the geodesy community. He has actively applied models of glacial isostatic adjustment and gravity data from the GRACE mission to address practical problems in ice sheet history, sea level variation, and short- and long-term solid Earth deformation. After his undergraduate training in physics at Grinnell College, Mark completed a Ph.D. with John Wahr at the University of Colorado. He was a postdoctoral fellow with Jerry Mitrovica at the University of Toronto and a geophysicist at the Harvard Smithsonian Observatory with Jim Davis. At present, he is a research scientist at Proudman Oceanographic Laboratory. Much of Mark’s research has been to develop and apply innovative approaches in geodesy to infer the sources of global sea level change. For example, Mark developed a technique to determine robust estimates of the annual amplitude and trend of the surface mass of glacier complexes, reducing the uncertainty in estimates of their contribution to recent sea level rise. He has applied this technique to glacier complexes in Alaska and Patagonia, confirming the rapid rate of their melting and demonstrating a new method to obtain results from relatively small scale features using GRACE data. Recently, Mark used results from GRACE to constrain ancient Laurentide ice geometries, providing conclusive evidence that the ice sheet was composed of two domes. This work resolved a long-standing debate about the morphology of the ice sheet and has put tighter constraints on how the ice sheet developed and evolved. More significantly, Mark isolated changes in the gravity field due to mantle convection and was able to test the hypothesis that the continental tectosphere is neutrally buoyant. In addition, Mark actively serves the geodetic community in several aspects. He is a respected member of the GRACE Science Working Team. He was meeting cochair of the UNAVCO annual meetings for 2 years and has been a member of the Stable North American Reference Frame (SNARF) Working Group. Mark Tamisiea has made impressively creative and noteworthy contributions to geodesy and is most deserving of this award. —Eric Leuliette, NOAA, Silver Spring, Md.

Response

I greatly appreciate receiving this award and would like to thank all of those involved in the process. I am very fortunate to be working at the boundary between geophysical modeling and geodesy at a time when both the sources and the number of geodetic data have been increasing so quickly. A prime example of this is new data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. I benefited considerably from finishing my Ph.D. while John Wahr’s group was studying the ability of a gravity mission to monitor the motion of water over the surface of the Earth. The GRACE data give unique insight into the temporal variability of length scales between those of the point-position information provided by GPS and absolute gravity observations and the very longest wavelengths revealed by earlier gravity missions, such as LAGEOS. Aided by modeling to assist in interpretation, the GRACE data have given us a better understanding of the current integrated mass balance of the glaciers and ice sheets, as well as the geometry and continuing impact of the late Pleistocene/early Holocene ice sheets. However, I believe sea level studies most clearly demonstrate the strength of combining geodetic data and modeling studies. My appreciation of the challenges of studying sea level more fully developed during my postdoctoral fellowship with Jerry Mitrovica and later working with Jim Davis. Geodesy plays a vital role in quantifying the changes in sea level, while modeling gives a means to integrating and interpreting the observations. As each of the measurement types is affected differently by a geophysical process, such as melting ice sheets or glacial isostatic adjustment, exploiting all of the data types simultaneously will give us greater ability to identify the relative contributions of each process. Incorporating oceanographic models and data into the analysis will give much better insight into all of the processes contributing to sea level rise. Thus I am looking forward to working with my new colleagues at the Proudman Oceanographic Laboratory to continue studying sea level variations. I would like to thank all my collaborators for their assistance and patience over the years, especially John, Jerry, and Jim; everyone involved in data collection and processing, particularly the GRACE mission team; as well as my friends and family for their support. —Mark Tamisiea, Proudman Oceanographic Laboratory, Liverpool, U.K.

Citation

Kristine M. Larson received the Geodesy Section Award on 23 May 2006 at the 2006 Joint Assembly in Baltimore, Md. The award is given in recognition of major advances in geodesy. Citation For the past 15 years, Kristine Larson has been at the forefront of research in the development and application of high-precision Global Positioning System (GPS) techniques to geophysical problems. Kristine received her bachelor’s degree in engineering sciences from Harvard University [Cambridge, Mass.] in 1985. She subsequently entered the Ph.D. program in geophysics at the Scripps Institution of Oceanography [La Jolla, Calif.]. Working with Duncan Agnew, her dissertation was one of the first to evaluate GPS accuracy and use it for geophysical studies. From 1988 to 1990, she was also a member of the technical staff at the Jet Propulsion Laboratory (JPL) [Pasadena, Calif.] where she worked with the team that developed the GIPSY [GPS Inferred Positioning System] software. In 1990, she joined the faculty at the University of Colorado, Boulder, where she is now a professor of Aerospace Engineering Sciences. Kristine’s science research focuses on measuring and interpreting crustal deformation with GPS. She published some of the first plate velocities based solely on GPS. She has also studied plate boundary zone deformation in Alaska, Nepal, Tibet, Ethiopia, California, and Mexico. In the latter collaboration with UNAM [Universidad Nacional Autónoma de México], episodic slip was first reported in Guerrero [Mexico]. Kristine’s research has also emphasized engineering development by pushing the temporal sampling of GPS to subdaily intervals. She has worked on problems as diverse as measuring ice sheet motion in Greenland, comparing atomic frequency standards, and volcanic inflation on Kilauea [Hawaii]. In 2003, she and her colleagues extended GPS into seismic frequencies with the first observations of seismic waves. These data were subsequently used to evaluate triggering of earthquakes outside the Denali rupture zone [Alaska]. Her group has more recently improved high-rate GPS analysis techniques for source studies of the San Simeon [California], Tokachi-Oki [Japan], and Parkfield [California] earthquakes. Larson has clearly established herself as a leader in the field of GPS geodesy. Her research program is extremely vibrant and has brought much benefit to the community. Her unique expertise is an outgrowth of exceptional engineering and scientific skill combined with great intellectual curiosity, creativity, and persistence. I am very grateful to Tim Dixon [University of Miami, Fla.] and Paul Segall [Stanford University, Palo Alto, Calif.], who strongly supported her nomination, and to the AGU Geodesy Section selection committee for making such an excellent choice. —Penina Axelrad, University of Colorado, Boulder

Response

I would like to thank everyone involved in nominating me for this award. As Penny says, my research program includes both science and engineering. Combining the efforts has forced me to continually challenge myself. Understanding the intricacies of GPS has helped me do better science; conversely, understanding the underlying physics of the problem I am trying to solve has motivated me to think of ways to improve the accuracy of GPS. The reward has come from working on so many interesting problems with a diverse cast of colleagues. In the mid-1980s, I went to graduate school convinced that I wanted to become a seismologist. Instead, I became involved with one of the first geophysics experiments designed with GPS. At this juncture there were very few classes on GPS, and there was no ‘how-to’ book. I was fortunate to be able to learn both from the strong GPS group at JPL and the engineers who developed VLBI (Very Long Baseline Interferometry) and SLR (Satellite Laser Ranging) for the Crustal Dynamics Project. I also had the good luck to work with many geodesists outside the United States on collaborative research projects. Today the use of GPS has become commonplace in geophysics, to the extent that a colleague of mine recently complained that his incoming students think plate tectonics was discovered by GPS. My own work on measuring plate tectonics with GPS always reminds me of my father’s stories about working as an engineer for the Deep Sea Drilling Project in the 1970s. In both cases, scientists and engineers worked together to build new tools for geophysics. I am grateful to many colleagues and cannot properly thank everyone in this short note, but I do want to especially acknowledge my family and Jim Rice [Harvard University, Cambridge, Mass.], Charbel Farhat [Stanford University, Calif.], Bob Miller, and George Rosborough. —Kristine M. Larson, University of Colorado, Boulder

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R. Steven Nerem received the Geodesy Section Award at the 2006 AGU Fall Meeting in San Francisco, Calif. The award is given in recognition of major advances in geodesy. Citation Steve Nerem has been at the forefront of geodetic and oceanographic research since receiving his Ph.D. from the University of Texas at Austin, in 1989. He is currently professor of aerospace engineering sciences at the University of Colorado, Boulder, and is a Fellow of the Colorado Institute for Research in Environmental Sciences. He also serves as associate director of the Colorado Center for Astrodynamics Research. Steve is a specialist in satellite geodesy and its applications to solid Earth physics, ocean dynamics, and related climate sciences. His work covers almost all areas of satellite geodesy: satellite orbit determination, satellite remote sensing, geodetic techniques (laser ranging, GPS, Doris, altimetry, GRACE), gravity field determination, vertical crustal motions, geocenter motion, timevariable gravity and application to Earth mass redistribution, ocean dynamics, ocean topography, and sea level change. He has also applied space techniques to measuring the gravity fields of Mars and Venus. Because these topics are interdisciplinary from the point of view of Earth sciences, Steve has become involved in a variety of disciplines. A recent contribution of Steve’s is his work on global mean sea level variations using satellite altimetry and tide gauges as well as the climatic causes of the observed change. Steve has published a series of basic papers on this topic. Determination of global mean sea level rise by satellite altimetry is now considered extremely robust, a necessary condition to detect any influence of global warming on the changing mean sea level. He has also contributed to the interpretation of data from the GRACE Gravity Recovery and Climate Experiment mission, especially for detecting ocean mass change and its contribution to global mean sea level. Steve actively serves the geodetic community in several aspects. Inside the American Geophysical Union, he was secretary of the Geodesy Section from 2002 to 2004, and is a former associate editor of JGR and Eos. He also gave the Bowie Lecture at the 2005 AGU Fall Meeting. To summarize, Steve Nerem has made impressively creative and enduring contributions to many areas of satellite geodesy and is very deserving of this award. I thank Anne Cazenave for her letter strongly supporting Steve’s nomination. —George Born, University of Colorado, Boulder.

Response

I would first like to thank everyone who helped nominate me for this award. I feel very fortunate to have chosen satellite geodesy as my field of research; over the years it has taken me into many different areas of Earth and planetary science. It was the positive influences in graduate school that led me down this path—Byron Tapley, Bob Schutz, George Born, John Ries, George Rosborough, and C. K. Shum, among others. I couldn’t have asked for a better first job at NASA Goddard Space Flight Center, where Dave Smith, Chet Koblinsky, Steve Klosko, Jim Marsh, and many others helped get my career off to a great start, collaborations that continue today. My academic career, first at the University of Texas and then at the University of Colorado, would not have been possible without the great experience I had at NASA. I have benefited from working with many collaborators over the years, but I would especially like to thank Eric Leuliette, Gary Mitchum, and Don Chambers for their ‘unselfish cooperation in research.’ I’d like to thank my graduate students for teaching me as much as I have taught them. Finally, I’d like to thank the many close friends I have made over the years working in this field; you really make me look forward to going to all those meetings! One of the most rewarding experiences of my career has been my involvement in the TOPEX/Poseidon and Jason satellite missions—it has been exciting both scientifically and culturally, a real model for how joint missions between two countries should be done. My sabbatical in France was a direct result of these collaborations, and I'd like to thank my many friends in Toulouse for a rewarding experience. Satellite geodesy is arguably the most multidisciplinary field in geophysics; it is the ‘glue’ that ties different fields together to help solve important problems affecting different components of the Earth system. I believe satellite geodetic measurements are going to become one of our most important tools in the next decade for figuring out how the Earth is changing and why, and I am truly grateful to be working during this exciting time in our field. —R. Steven Nerem, University of Colorado, Boulder.