2006-2007 Report to President

The Department of Earth, Atmospheric and Planetary Sciences (EAPS) has broad intellectual horizons that encompass the solid Earth, its fluid envelopes, and its diverse neighbors throughout the solar system and beyond. The Department seeks to understand the fundamental processes that define the origin, evolution and current state of these systems and to use this understanding to predict future states. The Department currently comprises 39 faculty, including two with primary appointments in Civil and Environmental Engineering, and over 110 research staff, postdoctoral appointments and visiting scholars.

EAPS is notable for emphasis on interdisciplinary problems. The Earth Resources Laboratory and the newly formed Kuwait Center at MIT bring together faculty, staff and students in intensive and multidisciplinary efforts to investigate geophysical and geological problems in energy and resource development. The Center for Global Change Science builds on the programs in meteorology, oceanography, hydrology, chemistry, and satellite remote sensing in the Schools of Science and Engineering. The Center joins with the Center for Energy and Environmental Policy Research to form the Joint Program on the Science and Policy of Global Change. This program conducts policy analysis and public communication on issues of global environmental change. With faculty from CEE, Chemistry, and EAPS, the Environmental Science Initiative fosters collaboration in both research and education on the physical, biological, and chemical interactions that define the Earth.

Educational Activities

— Teaching and curriculum. Changes in curriculum; current impact of educational trends.

Graduate Program

EAPS has vigorous graduate educational programs in geology and geochemistry, geophysics, atmospheres, oceans, climate, and planetary science. During this past academic year, 157 graduate students were registered in the Department including 67 students in the MIT/Woods Hole Oceanographic Institution (WHOI) Joint Program. Women constitute 40% of the graduate student population, and 31% of the graduate population is composed of international students.

The excellence of the EAPS Graduate Program is built not only on the strength of the teaching and supervision by the faculty, but also on the involvement of the EAPS graduate students in the activities of the Department. The students develop both formal and informal ways to improve their educational experience as well as student life. The Departmental Graduate Student Mentoring Program continues as a well-received approach to provide peer support for new students. Student involvement also contributed to an expansion and strengthening of the orientation program for new graduate students. EAPS awards a prize for Excellence in Teaching to recognize the superior work done by teaching assistants in many of our classes. Last year prizes were awarded to Nicholas Austin, Alexander Bradley, Einat Lev, Kyle Straub and Christophe Studnicki-Gizbert for their service during the academic year.

Undergraduate Program

EAPS continues to make the increase of the number of undergraduate majors in the department a priority. In AY04 we had a 95% increase in the number of undergraduate majors. In AY05 we again increased our undergraduate major population to the highest level in over 20 years. We are committed to maintaining and building upon this new level of undergraduate involvement. The Department’s commitment to fostering undergraduate research is illustrated by our annual award of the Goetze Prize for Undergraduate Research, presented for research conducted within UROP or for a senior thesis. At the 2006 Commencement, the Goetze Prize was awarded to graduating seniors, Francesca Demeo, Marion Dumas, and Solomon Hsiang.

EAPS presents the undergraduate student body with opportunities to become acquainted with the world from an Earth sciences’ perspective. The Department acts on its belief that EAPS should have a strong presence in the undergraduate program at MIT beyond our population of majors. In prior years this has expressed itself in the many UROP projects supervised by EAPS faculty, by participation in Freshman Advising Seminars and through department sponsorship of a weekly Undergraduate Seminar. The overwhelming majority of students in these programs have not been EAPS majors.

Faculty and Scientific Staff

— Personnel information. Appointments, promotions, departures, and retirements (with brief reflections on tenure/stewardship); leaves (where, for what purpose, and when returning?); awards and honors; significant professional activities and publications, or involvement in special projects or programs.

Professor Samuel Bowring was named MIT MacVicar Faculty Fellow in recognition of his commitment to undergraduate education.

Professor Kerry Emanuel will be appointed the Breene M. Kerr Chair on July 1, 2006, was selected to TIME Magazine’s TIME 100 list of people who shape our world, and was elected to deliver the Bernard Haurwitz Lecture at the American Meteorological Society's Annual Meeting in January 2007.

Professor Raffaele Ferrari will be promoted to Associate Professor with tenure on July 1, 2006 and was appointed as a member of the US Clivar Process Study and Model Improvement Panel.

(?) Dr. Mick Follows received the MIT Global Habitability Longevity Award, awarded for an outstanding contribution towards understanding long-term environmental trends affecting the Earth and its habitat for supporting life.

Professor Fred Frey received the Distinguished Alumni Award in the Department of Geology and Geophysics at the University of Wisconsin.

Professor Timothy Grove was elected President of AGU.

(?) Dr. Chris Hill was promoted to Principal Research Engineer.

(?) Dr. Lodovica Illari was promoted to Senior Lecturer and has led MIT’s team in the National Collegiate Weather Forecasting Contest for their 5th consecutive win.

(?) Dr. Vicki McKenna , Education Director, was awarded a MIT Excellence Award in the Unsung Hero category, representing one of the highest recognitions of MIT staff.

Professor Richard Lindzen served as a National University Lecturer in Hokkaido Japan, where he delivered as set of lectures on atmospheric waves and instabilities, was the keynote speaker at an international conference on precipitation measurement from space held in Taipei, and was the first recipient of the Leo Prize of Swedenís Walin Foundation for independent achievements in science.

Professor Paola Rizzoli was elected a Fellow of the American Geophysical Union in recognition of eminence in Geophysics.

Professor Peter Stone was named the Bernard Haurwitz Memorial Lecturer by the American Meteorological Society for pioneering contributions to the understanding of planetary general circulations and ocean-atmosphere feedbacks that operate on climate time scales.

Professor Roger Summons was elected a Fellow of the American Geophysical Union.

Professor Nafi Toksöz was named to the Schrock Professorship and was honored with the Harry Fielding Reid Medal of the Seismological Society of America for outstanding contributions in seismology and earthquake engineering.

Professor Rob van der Hilst was named President-elect of the Seismology Section of the American Geophysical Union.

Professor Benjamin Weiss will be appointed the Victor P. Starr Career Development Chair on July 1, 2006.

Professor Carl Wunsch will receive the 2006 Bowie Medal of the American Geophysical Union.

Professor Maria Zuber was awarded Brown University’s Horace Mann Medal, honoring distinguished graduate school alumni. She served on the National Academies ad hoc Committee on Women in Academe, and chaired the MIT Advisory Committee on the Lincoln Laboratory Director Search.

Current Research

Professor Richard Binzel is a science team co-investigator for the New Horizons mission to Pluto that successfully launched from Cape Canaveral, Florida on January 19, 2006. He continues observations of near-Earth asteroids using a NASA telescope in Hawaii, but operated remotely from the MIT campus. Research results include finding evidence that up to 20% of all "asteroids" near the Earth may in fact be dormant or extinct comets. Professor Binzel also led a group of MIT alumni on an Egypt expedition to view the March 29, 2006 total solar eclipse of the Sun.

Professor Samuel Bowring’s research group is working on two major themes, the origin and evolution of continental lithosphere and using high-precision geochronology to sequence the history of life. Professor Bowring’s leadership in geochronology contributed to the approval of the NSF Earthtime Initiative, that will create a virtual network of geochronology labs that will sequence Earth history at better than 0.1 %.

Professor Edward Boyle and his group have continued their work on trace element chemical oceanography and marine paleoclimatology. This year's major activity was a research cruise in the western North Atlantic to trace the advective transport of lead by the upper and lower North Atlantic Deep Water. In addition, they obtained the first data on the Zn isotopic composition of deep seawater as well as measurements of plankton from throughout the North Pacific and North Atlantic. Professor Boyle has also spent time organizing a new international program to determine the global distribution of trace elements and their isotopes (GEOTRACES).

Professor Clark Burchfiel’s main research effort continues from twenty-four years of work in China and focuses on the tectonic evolution of the eastern part of the Tibetan plateau and regions to the southeast into Indochina. A second area of research has been in the Balkan region of southern Europe where the Cenozoic history of extensional tectonism has yielded a complex evolution.

Professor James Elliot, his students, and research scientists successfully observed a stellar occultation by Charon, in collaboration with our Williams colleagues. We established a stringent upper limit on a possible atmosphere and accurately determined the radius, from which we derived a density that is consistent with a collisional formation of the Pluto-Charon binary.

Professor Kerry Emanuel’s efforts were focused almost exclusively on the effects of climate change on hurricane activity. He published a paper in Nature in August 2005 showing that hurricanes are already responding to global warming by becoming more intense and lasting longer. Subsequent work analyzing observed hurricanes and running advanced numerical models supports these conclusions. In addition, we made major strides forward in developing advanced techniques for hurricane risk assessment, including the effects of past and projected climate change.

Professor Brian Evans and coworkers are working to understand the evolution of transport properties, including permeability and electrical resistivity, and of mechanical properties, including brittle fracture strength and the plastic flow strength. One important result that has emerged is that pore structures may be altered quite rapidly, in a geologic sense.

Professor Raffaele Ferrari and his group are studying the processes that control the heat transport of the global ocean and their impact on the Earth's climate. They showed that most of the heat transport is associated with wind-driven circulations in the upper kilometer of the world's oceans. This is in contrast to a large literature that emphasizes the role of abyssal circulations. The implication is that the ocean's role in climate and climate change is mostly associated with shifts in wind patters at midlatitudes and less so with cooling or warming at high latitudes. Raffaele Ferrari is also the leader of a Climate Process Team, an NSF sponsored project involving ten different US universities, aimed at improving models for studies of climate and climate change. The team has focused on developing new turbulent closures for the upper ocean circulation. The new schemes have been implemented in the climate models at GFDL and NCAR and improved the models skill in reproducing observed ocean heat transport. The team has been funded for additional two years to study the implications of these results for future climate change.

Professor Fred Frey’s current research focuses on the largest terrestrial volcanoes which occur in mid-ocean settings distant from the volcanism associated with plate boundaries. Recent Hawaiian volcanoes form two parallel trends, and our emphasis is to determine geochemical characteristics of the lavas from these trends to obtain spatial and temporal constraints on the Hawaiian magma source (hotspot). The goal is to understand the processes that created the hotspot. In 2007 we are scheduled to study another hotspot track of volcanoes, the 5000 km submarine Ninetyeast Ridge in the Indian Ocean. Here the first order objective is to determine how the paleolatitude of volcano formation varies with eruption age in an effort to define hotspot motion within the mantle. In particular, did Pacific (Hawaiian) and Indian Ocean hotspots move differently?

Professor Tim Grove and his colleagues have been measuring the solubility of helium in minerals and melts, and have produced the first experimental determination of the solubility of this important noble gas. They have found that He is more soluble in the most common mineral in the Earth’s mantle, olivine, than the elements U and Th. This is important because it allows a new interpretation of the significance of high 3He/4He that is found in some mantle reservoirs.

Professor James Hansen is exploring the impact of model inadequacy and nonlinearity on state estimation, ensemble construction, and probabilistic forecasting. He is developing a laboratory analog of atmospheric/oceanic flow for both research and education purposes.

Professor Thomas Herring is using global positioning system and very long baseline interferometry data to develop geophysically based models of changes in the rotation of the Earth and Earth deformations on global and regional scales. He is also using satellite based laser altimetry to study earth and ice sheet height changes. The geodesy and geodynamics group in the department is using high precision GPS measurements in many different study areas. These areas include the tectonic deformations over much of the southern Eurasian plate boundary, southern New Zealand and the western United States. Processes on time scales of years leading up earthquakes, days to years in the domain of post seismic deformation, and seconds for surface wave propagation during earthquakes, are all studied. The group is also involved in monitoring and modeling human induced deformations in oil fields. To support these activities and to improve even further the accuracy of GPS measurements, MIT is a data Analysis Center for the International GPS service and acts as the GPS Analysis Center Coordinator of the National Science Foundation Plate Boundary Observatory (PBO), which is part of the EarthScope program.

Professor Richard Lindzen and his research group are working on a number of different problems in the broad areas of climate and atmospheric dynamics. In a major study, they are working on improving techniques for using geostationary satellite data to measure rainfall and to determine cumulus mass flux, which is important in its own right, and potentially important for assessing climate feedbacks as well. These issues are also being addressed with space based microwave measurements where sophisticated statistical techniques are used to overcome the sampling problems arising from low orbits, and verification techniques involving ground based radar have been developed as well. In addition, work has been done in collaboration with Maria Zuber and her group to show that atmospheric tides on Mars are incapable of accounting for the needed tidal dissipation, and that the dissipation, therefore, must come from the solid planet.

Professor John Marshall is studying the role of the ocean in climate and climate variability. His recent focus has been on the dynamics and (in collaboration with Mick Follows and his group) the biogeochemistry of the southern ocean. As part of MIT’s Climate Modeling Initiative, he has been studying geometrical constraints on ocean heat transport and the partition of heat transport between the atmosphere and ocean, in the context of highly idealized coupled atmosphere-ocean-ice models.

Professor F. Dale Morgan assumed the co-directorship of the Kuwait Center at MIT, a joint effort by the Institute and the country of Kuwait to perform joint research on scientific and technological aspects of hydrocarbon identification and extraction, including environmental impacts.

Professor Ronald G. Prinn and Dr. Yu-Han Chen have used global observations, an atmospheric circulation model and statistical inverse methods to estimate 1996-2001 emissions by month of methane which is an important greenhouse gas. They conclude that energy-related emissions are smaller and rice paddy and biomass burning emissions are larger than previously thought. They also attribute the unusually large 1998 global increase in methane largely to enhanced global wetland emissions in this very warm El Nino year.

Professor Paola Malanotte-Rizzoli has continued to work on transport and heat exchanges between the subtropical and the tropical Atlantic Ocean and how they affect the global thermohaline circulation and development of ensemble data assimilation approaches to improve the predictability of Ocean Circulation Models. As Director of the MIT/WHOI Joint Program in Oceanography, she continues to play an important role in the graduate education in Oceanography.

Professor Stéphane Rondenay’s group is involved in two key areas of solid earth seismology: the acquisition of high-quality data sets from seismic arrays, and the development and application of new teleseismic approaches to image structure in the earth's crust and mantle. His principal recent work is seismic imaging of the upper mantle beneath a craton in northern Canada.

Professor Daniel Rothman's research in 2006 centered on theoretical studies of geobiology and field studies of geomorphology. Recent work in geobiology has centered on understanding Earth's carbon cycle. In an attempt to explain patterns in marine respiration, Rothman and his group have discovered a general mechanism that leads to a slow logarithmic decay of organic matter. Analysis of the available data shows that the logarithmic decay is ubiquitous. These findings should lead to a new understanding of the short-term controls on atmospheric CO2 levels and the long-term rise of atmospheric oxygen. Rothman's recent work in geomorphology has concentrated on an unusual field site on the Florida Panhandle where large, kilometer-scale channels are incised by subsurface seepage flows. During the 2006 Spring Break, Rothman and Professor David Mohrig organized a one-week student field trip to the area, where many unusual aspects of seepage-driven erosion were observed and analyzed.

Professor Sang-Heon Dan Shim and his group have studied hydrogen bounded in the crystal structure of mineral Ca(OH)2 at high pressure in order to understand hydrogen (or water) cycle in the deep Earth’s interior. Previous measurements have proposed that amorphization of hydrous minerals in the subducting slabs is responsible for the deep focus earthquakes. Using synchrotron X-ray diffraction combined with laser Raman spectroscopy using a new system in my lab, we revealed that earlier observations of the amorphization of hydrous minerals is due to differential stresses in the pressure devices of the previous studies. We showed that hydrous minerals undergo phase transitions to crystalline phases instead of amorphization under hydrostatic stress conditions. This result is in the process of being written up for publication in a scientific journal. We also studied an analog hydrous compound [Cd(OH)2] which has very similar properties as Ca(OH)2. This study confirmed similar behaviors in this material at high pressure which supports our result on Ca(OH)2 [Shim et al., 2006, Physical Review B, in press]. We have also studied the texture of newly discovered phase, “post-perovskite”, stable at the lowermost mantle (2500-3000-km depth from the surface of the Earth). The lowermost mantle has been expected to play an important role for the mantle convection and tectonics. Seismologists have observed splitting of S-waves in this region of the mantle. However, the source of the seismic observations has not been well understood. Recently several groups including us have found that the dominant mantle mineral undergoes a major phase transition at the pressure-temperature conditions of the lowermost mantle, “post-perovskite”, [Shim et al., 2004, Geophysical Research Letters 31, L10603] and suggested that texturing of this mineral may explain the enigmatic seismic observations. We have recently showed that the texturing of the post-perovskite changes with stress conditions and temperature, which has significant implications for the interpretation of the seismic observations [Santillan et al., 2006, Geophysical Research Letters, in press]. We are also working with two undergraduate students. Caitlin Murphy is building an X-ray diffraction database of Martian minerals and developing data analysis methods for the future Martian X-ray missions in collaboration with my group and Kavli institute at MIT. Sarah Slotznick is conducting high-temperature Raman spectroscopy measurements of important mantle minerals at my lab using the newly developed nanosecond time-resolved Raman spectrometer.

Professor Peter Stone and research scientists, Chris Forest and Andrei Sokolov, published their latest analysis for how 20th temperature changes constrain major uncertain climate parameters. For the first time they were able to get a strong constraint on how rapidly heat is being mixed into the deep oceans. The result shows that current state-of-the art climate models are overestimating the rapidity of this mixing, and are therefore underestimating how much warming will occur over the next century.

Research in Professor Roger Summons’ Geobiology laboratory addresses biogeochemical aspects of the major transitions in Earth history. Isotopic and hydrocarbon biosignatures indicate that the radiation of multicellular life in the Cambrian was immediately preceded by rapid oxidation of reduced carbon and sulfur species in the ocean at the end of the Proterozoic. Studies of photosynthetic pigments preserved in sediments around the Permian-Triassic mass extinction suggest that the ocean reverted to a state of anoxia and euxinia for a prolonged period during this event. Similar conditions prevailed during the biotic extinction of the late Devonian consistent with the hypothesis that several of these events have a common cause and that hydrogen sulfide was possibly the main agent of extinction. Our studies of ancient sediments are supported by several lines of research on contemporary microorganisms and biogeochemical processes in modern environments. The Geobiology Laboratory directly supports the research of 3 postdoctoral fellows, six graduate students and three undergraduate (UROP) students.

Professor M. Nafi Toksöz , working with his postdocs and Ph.D. students, developed a new method for determining focal depths of regional earthquakes. Among the earthquake hypocentral parameters, the depth of focus is most prone to error because of the tradeoff between the depth and origin time. The new method, based on time reversed acoustic (TRA) concepts, back propagates the seismic waves to the source. Because of the randomness of the propagation path, the procedure is simplified to a correlation operator. The method is robust and straightforward to implement.

Professor Rob van der Hilst and his co-workers analyzed broadband seismic observations to reveal variations in mantle temperature and bulk composition below 1000 km depth under the northern Pacific and the Americas. With a technique adapted from application in oil industry, they also began an ambitious effort to image in unprecedented detail the Earth's core mantle boundary. van der Hilst also led a seismological field campaign in southwest China to image mantle structure and understand regional tectonics and seismicity.

Professor Kelin Whipple and his group showed that the details of the erosion processes are critically important to the strength and nature of the dynamic coupling between climate-driven erosion and tectonics, controlling the sensitivity of mountain-belt width, topographic relief, and rock uplift rate to climatic and tectonic variables. His work clarified how climate and tectonics combine to exert a fundamental control on particle paths through the crust.

Professor Jack Wisdom has been studying the evolution of the lunar spin axis. Prior work has assumed that the inclination of the lunar orbit is constant and that the node regresses uniformly. His new work takes into account the nonconstant inclination and nonuniform regression of the node as determined from averaged models of the motion of the lunar orbit.

Professor Carl Wunsch and colleagues are continuing their efforts to describe and understand the global ocean circulation, its variability, and impact on climate change. They combine global measurements of the ocean from a 15-year period, with over-ocean meteorological estimates, and a numerical general circulation model in a gigantic least-squares fit (more than 10^11 variables). The result is the best existing estimate of the ocean circulation from 1992-2004 and permits them to calculate such societally important quantities as trends in the North Atlantic circulation, the global rise in sea level, and many other phenomena.

Professor Maria Zuber and colleagues completed development of a laser ranging device that has been launched on the MESSENGER mission to Mercury, and were selected to develop and build a laser altimeter for the Lunar Reconnaissance Orbiter, to be launched in 2008. Her group is studying the variability of the Martian atmosphere and the annual and interannual variations of Martian volatile cycles.