MIT Reports to the President 1999–2000
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. We seek to understand the fundamental processes defining the origin, evolution and current state of these systems and to use this understanding to predict future states. The Department comprises 35 faculty, including two with primary appointments in Civil and Environmental Engineering, 185 graduate and undergraduate students, and 103 research staff, postdoctoral appointments and visiting scholars. EAPS is notable for its collaborations with other MIT Departments and Schools to address complex interdisciplinary problems.
EAPS has vigorous graduate educational programs in geology and geochemistry, geophysics, atmospheres, oceans, climate, and planetary science. Each disciplinary area of EAPS continues to be ranked among the top graduate programs in the country, with most areas being rated either first or second nationally. The EAPS graduate program currently focuses on the Ph.D. degree, which is the goal of about 90% of its graduate students. During the past academic year, 151 graduate students were registered in the Department including EAPS students in the MIT/Woods Hole Oceanographic Institution (WHOI) Joint Program. Of these 107 are U.S. citizens and 44 are international students. Women constitute 44% of the graduate student population. Sixteen Ph.D. and fifteen S.M. degrees were awarded during the past academic year (1999—2000).
The new EAPS Master’s Degree Program in Geosystems graduated its third class this year. The program’s novel curriculum is designed to educate geoscientists in system-level analysis and prepare them for professional careers in high-technology industries concerned with complex geosystems. The degree requirements comprise 108 units of course work, including the novel two-semester, 30-unit Geosystem basetrack subject, and a masters thesis. All five of the entering students successfully completed the course work in two semesters; with all five graduating in June.
Another relatively new degree program is administered by the department’s Program in Atmospheres, Oceans and Climate (PAOC). This new Ph.D. in Climate Physics and Chemistry has 12 students currently enrolled. Enrollment in the PAOC graduate degree programs continues to slowly increase. Two recent faculty departures now present a challenge for us to sustain the breadth of the overall PAOC program, which also includes degrees in atmospheric science and joint degrees with WHOI in oceanography, and is arguably unique in the world.
A bi-annual prize has been developed to recognize and reward the efforts of outstanding EAPS Graduate Teaching Assistants. Winners during the past year include Jason Goodman, Greg Lawson, Galen McKinley, and Noah Sayder.
EAPS continues to maintain a strong presence within the undergraduate program at MIT. The Department continues to offer a wide variety of Freshman Advising Seminars each Fall with 10 faculty members participating each of the past three years, advising almost 10% of MIT's freshman class. A new undergraduate seminar has been developed to introduce newly declared sophomore majors to the broad research interests of the faculty. This seminar was very well received during its inception and is now being modified and expanded to include one-on-one mentoring by faculty members in the areas of technical writing and oral communication. Next year EAPS will have 14 new majors which is a very significant increase above the current year (5 new majors). Professor Kip Hodges was the recipient of a substantial d’Arbeloff Grant to support development of a new multi-disciplinary project-based learning experience for freshman entitled, "Mission 2004 and Beyond."
The EAPS Independent Activities Program (IAP) continues to be one of the most vibrant at MIT, and faculty have maintained a healthy Undergraduate Research Opportunities Program (UROP). Opportunities for IAP field experience included trips to Lowell Observatory in Flagstaff, Arizona, the NASA Goddard Space Flight Center in Maryland, and a geoscience field camp in Nevada.
The Bachelor of Science curriculum was reorganized several years ago to include three areas of concentration: geoscience, physics of atmospheres and oceans, and planetary science and astronomy. Each concentration encompasses a set of required courses, a sequence of field and laboratory subjects, and independent study or thesis preparation. Historically, students have primarily chosen to specialize in either geoscience or planetary science and astronomy. In the past two years however, there have been an increasing number of students (5 to 6) pursuing studies in the physics of atmospheres and oceans. Within this concentration area, a new Institute Laboratory course has been developed that permits undergraduates to develop and perform experiments related to the general circulation of the atmosphere and the day-to-day sequencing of weather events. EAPS undergraduate enrollment comprised 30 majors and 17 minors during 1999—2000.
Professor Richard Binzel was elected as a Fellow of the American Association for the Advancement of Science (AAAS).
Professor Edward Boyle was awarded the Patterson Medal of the Geochemical Society for his research in environmental geochemistry and was also elected a Fellow of the AAAS.
Professor John Edmond was awarded the Urey Medal of the European Association for Geochemistry.
Professor Frederick Frey was elected a Fellow of the Geochemical Society and a Fellow of the European Association for Geochemistry.
Professor Paola Malanotte-Rizzoli was elected President of the International Association for the Physical Sciences of the Ocean (IAPSO) which comprises more than 100 nations and more than 5,000 international members.
Professor Mario Molina received the UNEP’s Sasakawa Prize.
Professor Ronald Prinn was elected and served his term as Chair for Atmospheric and Hydrospheric Sciences of the American Association for the Advancement of Science.
Assistant Professor Kelin Whipple was promoted to Associate Professor.
Professor Carl Wunsch received the Henry Stommel Research Prize from the American Meteorological Society.
The department currently has active faculty searches in six exciting areas. The first is in Planetary Science which is making dramatic advances toward understanding the formation and evolution of our solar system and other planetary systems. Observations made using recent advances in both spacecraft and earth-based sensors are enabling the development of more physically realistic models of dynamical interactions between planetary bodies, as well as the internal constitution and thermal history of individual planets and their moons.
The second faculty search is in Crustal Geophysics. Of growing importance is the need for advances in our understanding of the structures and processes of the upper crust. Areas of interest include seismic imaging, electromagnetic wave propagation, flow through porous media, sediment transport dynamics, reservoir structure, relationships among subsurface structures, and kinematics and dynamics of crustal deformation. All these areas are relevant to present and planned new activities in the Earth Resources Laboratory.
The third faculty search is in Geobiology. We envision this emerging new field to encompass research that includes the origin of life, evolutionary and developmental biology, microbial biology, and the interactions between ecosystems and climate. There are numerous opportunities for interactions and collaborations between geobiologists and faculty in our programs in climate, planetary geology, and earth geology as well as faculty in the Civil and Environmental Engineering and Biology Departments. The time is right for the expansion of the department into this exciting new field.
The fourth faculty search is in Atmospheric, Oceanic and Climate Sciences. We aim to enhance our existing programs in meteorology, oceanography and climate research including ongoing work in the Center for Global Change Science’s Climate Modeling Initiative. The applicant may have any focus: theoretical, experimental, or observational; applicants capable of initiating and/or taking full advantage of the interdisciplinary nature of the department are especially being sought.
The fifth faculty search is in Experimental Geophysics and Geochemistry. We are seeking an outstanding scientist in the area of experimental geophysics and geochemistry who studies the physics and chemistry of Earth materials. Areas of interest include, but are not limited to: mechanical properties, including the study of multiphase materials or materials undergoing chemical reactions; thermal transport, fluid transport, acoustic and/or electrical properties, including flow of granular material, fluid flow through porous materials, transport of magma and flow in the mantle; and high-pressure mineralogy, mineral physics and phase transitions in planetary interiors.
The sixth faculty search is in Paleoclimate Science. We seek creative applicants with broad research interests who have a strong understanding of fundamental biological, geological, chemical, and physical processes affecting the evolution of the earth's climate. The position is open to outstanding candidates in all areas of paleoclimatology. Observational and experimental approaches are favored; applicants capable of initiating and/or taking full advantage of the interdisciplinary nature of the department are encouraged to apply.
The department continues to pioneer work in new interdisciplinary areas. The Earth Resources Laboratory is broadening its base to include a wider range of geophysical, geological, and environmental topics. The Center for Global Change Science (including the Climate Modeling Initiative) and the Program in Atmospheric, Oceans and Climate continue to foster cross-fertilization among all areas of the earth sciences that control the climate system. Research activities are gradually broadening so that geologists are now working with oceanographers and atmospheric scientists, and models of the climate system have been constructed both for the modern system and for times deep in the geological past. A new faculty group interested in co-evolution of the geosphere and biosphere has formed and is focussing initially on understanding the great extinctions in earth’s past. New geobiology faculty will further enhance interactions between the geological and climate sciences in the Department. Department faculty also continue to play leading roles in the MIT Joint Program on the Science and Policy of Global Change.
Professor Richard Binzel and Dr. Schelte Bus were responsible for approval by the International Astronomical Union (IAU) in honoring the Institute with the naming of asteroid (4523) MIT, a 15 km object orbiting in the main-belt between Mars and Jupiter. Also honored by the IAU was Neil Pappalardo. The naming of asteroid (4241) Pappalardo recognizes his support of MIT’s participation in the Magellan telescope project. The Pappalardo asteroid is 5 km across and also orbits in the main asteroid belt.
Professor Samuel Bowring’s group continues their work on calibrating the tempo of mass extinction and evolutionary radiations concentrating on the Cambrian explosion and the end-Permian extinction. In addition, Bowring's graduate student Mark Schmitz is using lower crustal xenoliths from the abundant diamond pipes in southern Africa to constrain the thermal history of the lower crust and in particular the time-scale of the decay of orogenic geotherms.
Professor Edward Boyle is following the decadal-scale evolution of lead in the ocean which has been introduced by human activities. His group is also working on the chemical characterization and variability of iron (an essential limiting nutrient in marine environment). He is also working on the relationship between deep ocean circulation and past abrupt changes in global climate.
Professor John Edmond’s main effort has been on the chemistry of the big rivers (Mekong, Salween, Yangtze and Yellow) that arise on the Eastern Tibetan Plateau and in Western Sichuan. This is a continuation of previous work on the Tropical rivers of South America and the Arctic and Sub-Arctic rivers of Eastern Siberia. Two major expeditions have been completed with great success, one in the Summer of 1999 and another, just finished, this summer. Monitoring stations to determine the dissolved load transport into the Three Gorges Dam have also been established.
Professor James Elliot, graduate student Susan Kern, and colleagues at Lowell Observatory and the Ohio State University are conducting a survey with the Mosaic cameras at the national observatories for solar system bodies orbiting the sun beyond Neptune. So far they have found nearly 60 of these bodies, which they plan to study with the first Magellan telescope when it comes on line in 2001.
Professor Kerry Emanuel developed a new model for predicting the intensity of hurricanes. Although the model is extremely simple and was developed for pedagogical purposes, it has proven to be so much better than existing models that it is being used for actual hurricane intensity prediction by the National Hurricane Center.
Professor Brian Evans, Dr. Joerg Renner and Dr. Greg Hirth are measuring the strength of partially molten peridotites. The experiments are unique in that the pressure of the magma is maintained separately, and thus, the experiments simulate the genesis and migration of melt in volcanic source regions. Uli Mok, Yves Bernable, Wenlu Zhu and Evans have completed experiments that explore the changes of permeability during diagnoses of sedimentary rocks. Surprisingly, the permeability of the rocks changes very quickly even through the total porosity remains relatively constant. The microstructure produced in the experiments are very similar to those found in petroleum source rocks in natural formations.
Professor Frederick Frey’s current research involves, dating of rocks cored from the Indian Ocean seafloor during Ocean Drilling Program Leg 183. Frey and M. Coffin (as co-chief scientists) show that ancient continental rocks with ages ranging from 530 to 2550 million years form part of the Kerguelen Plateau: a very large volcanic province which formed a subaerial landmass as a result of extensive volcanism 110 million years ago. The finding of ancient continental rock in this younger oceanic province was unexpected.
Professor Grotzinger has started a new field project in the Sultanate of Oman, where strata deposited at the Precambrian-Cambrian boundary are extremely well preserved. These rocks contain the best proxy records of environmental change that led directly to the Cambrian radiation of metazoan organisms.
Professor Tim Grove and colleagues have been investigating processes that lead to the unique trace element abundance signatures observed in subduction zone magmas. They find that a water-rich fluid released by the dehydration of minerals carried in the subducting slab contributes most of the trace element signature to subduction zone magmas. This trace element rich fluid, "flux-melts" the overlying mantle as it ascends into the hot, shallower portion of the mantle wedge.
Professor Bradford Hager and his students developed a novel algorithm that made it possible to include realistic simulations of small-scale thermo-mechanical processes at subduction zones in large-scale numerical models of mantle convection. This advance made it possible to carry out more realistic computations of Earth's thermal history and energy budget.
Professor Thomas Herring, his students, and colleagues have been using Global Positioning System measurements to study deformations occurring before, during, and after earthquakes in California, Turkey and Central Asia. He has also been collaborating with colleagues in India and Canada on studies of the Earth's deep interior using very long baseline interferometry measurements of changes in the rotation of the Earth. He has also run a workshop for Cambridge middle school teachers on the use of data in Earth Sciences and made presentations to Lexington high school students.
Professor Richard S. Lindzen is actively investigating a possible new climate feedback which he refers to as the "Iris Effect." Using satellite cloud data, backed up by simple theory, he and colleagues have found that upper level cloud cover in the tropics decreases strongly with increasing surface temperature in such a manner as to stabilize surface temperature. The effect is being incorporated into several large-scale climate models in order to determine the impact of the Iris Effect on climate sensitivity and air-sea coupling.
Professor Paola Malanotte-Rizzoli and her collaborators have focussed on three major research issues:
Zhang Peizhen of China’s State Seismology Bureau, Will Downs of Northern Arizona University, and Senior Research Scientist Peter Molnar have shown that sedimentation rates around the world increased at 2.5-3 million years ago when global climates abruptly became colder and drier. This poses the question: how did climate change effect increased erosion rates? They suggest that the switch from a stable climate to one that oscillates rapidly and with large changes maintains the erosive system in disequilibrium and therefore prevents it from approaching a steady state of slow erosion.
Recent achievement in Professor Mario Molina’s group include experiments and theory leading to an improved understanding of phase transitions in tropospheric aerosols and their role in climate change; investigations of important reactions between gaseous free radicals and organic atmospheric aerosols; and studies of the connections between economic, social and scientific aspects of the air pollution problem in megactities of the developing world.
Professor Reginald Newell flew aboard a NASA research aircraft measuring atmospheric trace constituents in a tropical Pacific mission in the spring of 1999. He and his colleagues discovered a duct of sinking motion along the equator about 800 km wide and several thousand km long, bordered by two regions of rising motion and cloud which extended to about 11 km altitude. The climatology of the duct, its possible role in acting as a double barrier to the north-south transport of trace constituents, and the physical mechanisms responsible for it, are presently under study.
Studies of atmospheric chemistry using multi-dimensional models in Professor Ronald G. Prinn's group (especially Drs. Chien Wang and Monika Mayer) have identified and quantified the very significant effects of the non-linear chemistry in polluted urban areas on the chemistry and climate at regional and global scales. Wang and Prinn have also demonstrated the significant role of deep convection and its associated lightning on the chemistry of ozone in remote areas.
In their recent studies of natural landscapes, Professor Daniel Rothman and his group have carefully evaluated the theoretical and empirical evidence in favor of scaling and universality in river networks. In a new area of interest, Rothman has studied concurrent paleontological and geochemical records for the past 500 million years, and has found quantitative evidence that global carbon dioxide levels, and the carbon cycle itself, are significantly coupled to global biodiversity.
Professor Peter Stone and his former student Dr. Amy Solomon have used an efficient three-dimensional numerical model to study the interaction of atmospheric eddies (cyclones and anti-cyclones) with the mean state of the atmosphere. They find, as has been frequently speculated, that the eddies are very efficient at homogenizing the potential vorticity structure of the mid-latitude atmosphere, but only in the lower troposphere. The result is robust over a wide range of forcing parameters.
Prof. M. N. Toksöz, along with his colleagues and students, have been deeply involved with the tectonic and seismological studies of two devastating earthquakes that occurred in Turkey in August and November 1999. These two earthquakes have increased the probability of a major earthquake further west on the North Anatolian Fault, that could affect a population of 13 million people near Istanbul. The MIT team has increased their geophysical monitoring to better evaluate the earthquake hazard in the region.
Using a variety of seismic imaging techniques, Professor Robert D. van der Hilst and his research group are studying the lateral variation in seismic properties (including anisotropy), the variations in depth to major interfaces, and the presence of scatterers deep in Earth's interior. Recently, they made significant progress toward mapping mantle anisotropy and crustal thickness beneath Australia, which will help to understand the long-term deformation and evolution of continents, and lead toward improving tomographic images of Earth's lowermost mantle.
Professor Kelin Whipple’s current research agenda represents an integrated effort to discover: the quantitative relationships between climate, tectonic setting, rock type, and the elevation and relief of mountain belts; the controls on the timescales of mountain building and decay; and the nature of the sediment supply signal delivered to depocenters (both on-shore and off-shore) during an orogenic cycle. Exciting new developments in recent months include minimum estimates of landscape response time that argue against the often-invoked steady-state assumption, analysis of the role of sediment flux in modulating river incision rates, and refinement of a river incision law to allow prediction of patterns and rates of tectonic uplift in suitable field localities.
Professor Jack Wisdom has continued his investigations of the non-linear dynamics of coupled core-mantle systems subject to astronomical forcing. Earth and Venus can evolve chaotically as tidal friction carries them through resonances between the core precession period and the orbital period. Consequences for the thermal history of Earth and Venus are being investigated. He has also finished his book on classical mechanics with Professor Gerald Sussman in EECS. The book presents mechanics from a modern non-linear dynamics perspective, and makes extensive use of simulation for active exploration of non-linear phenomena in mechanics.
Professor Carl Wunsch and his group are working with collaborators at several other institutions on estimating the complete global ocean circulation as it changes from day-to-day. It is now possible to produce three-dimensional oceanic fields and properties (such as heat flux) as they vary under atmospheric forcing and internal instabilities using a general circulation model and the new global oceanic data sets.
Professor Maria Zuber and colleagues used gravity and altimetry data from their experiments on the Mars Global Surveyor spacecraft to produce the first high integrity global models of the structures of the crust and lithosphere of Mars. The models yielded a new view of the early thermal evolution of Mars, including the history of water and climate. Professor Zuber’s laser ranging instrument on the NEAR Shoemaker spacecraft has yielded the highest quality shape model ever produced for a solar system small body, near Earth asteroid 443 Eros.
More information about this department can be found on the World Wide Web at http://www-eaps.mit.edu/.
Ronald G. Prinn
MIT Reports to the President 1999–2000