Roosevelt Island Research Articles

Aerial Advancement

Detailed software models, together with careful analysis of hundreds of load case combinations, enabled an international design team to extend the service life of New York City’s Roosevelt Island Tram by at least 30 years. The team’s efforts helped avoid unnecessary structural reinforcements while creating lightweight support elements critical to the new system.

Roosevelt Island: Exception to a City in Crisis

Today, New York City’s Roosevelt Island stands as living proof that the public sector can produce a mixed-income and mixed-race neighborhood from scratch. Its successes contrast with typical perceptions of government housing failure and indicate that with determined leadership, stable funding, and a good location, the public sector can create healthy, heterogeneous neighborhoods. This article examines the process of designing and constructing Roosevelt Island to illustrate how and why local actors took advantage of favorable conditions and made important political choices to achieve their commitments, even as political and financial support for such developments deteriorated. In light of the often dismal reputation of government housing policy in the United States, Roosevelt Island’s success—unique in its mixed-income legacy—offers lessons about effective city governance in the face of dwindling national support.

New Town in the City: Edward J. Logue and His Vision for Roosevelt Island, New York

In 1968, Governor Nelson A. Rockefeller succeeded in securing the establishment of the New York State Urban Development Corporation (UDC), with Edward J. Logue as its chief executive officer. Of the many projects initiated during his tenure in that position, Logue considered the development of Roosevelt Island the most significant. On that island, in the middle of New York City’s East River, he attempted to realize his vision of an ideal urban community. Although there were challenges to overcome and compromises to be made, Roosevelt Island is today one of the city’s most desirable residential communities.

Grounding-line basal melt rates determined using radar-derived internal stratigraphy

AbstractWe use ice-penetrating radar data across grounding lines of Siple Dome and Roosevelt Island, Antarctica, to measure the spatial pattern, magnitude and duration of sub-ice-shelf melting at these locations. Stratigraphic layers across the grounding line show, in places, a large-amplitude downwarp at, or slightly downstream of, the grounding line due to sub-ice-shelf basal melting. Localized downwarping indicates that melting is transient; melt rates, or the grounding line position, have changed within a few hundred years in order to produce the observed stratigraphy. Elsewhere, no melt-related stratigraphic signature is preserved. In part, heterogeneity in the amount of sub-ice-shelf melt is due to regional circulation patterns in the sub-shelf cavity, but local (on the order of tens of kilometers) heterogeneity in the melt pattern may reflect small differences in the shape of the ice-shelf base at the grounding line. We find that all of the grounding lines crossed have been in place for at most ∼400 years.

Music Fundamentals

[1] Late one Friday afternoon, as I watched members of my ear-training class write the results of a rhythmic dictation on the board, I realized that one student was staring at the permanent staff lines, as though transfixed. As I approached him, he looked at me and earnestly asked, "Professor, what are we doing here?"[2] This anecdote provides just one example of the kind of teaching situation about which one does not learn a great deal in graduate school. Socioeconomic circumstances often find the least experienced teachers in the most complex classroom environments. Because disability inextricably threads its way through the intricate social fabric of gender, class, and race, it's not surprising that many-though certainly not all-students with disabilities choose accessible, affordable, urban colleges. Hunter College, part of the CUNY system, is one such institution. At least partially because of its proximity to bus and subway transportation, low tuition, and flexible class schedule, disabled students have become a fixture of classes at Hunter. In addition, Hunter is on a direct subway line from Roosevelt Island, where many disabled New Yorkers have found community and accessible apartments for decades (Hughes 2007). Thus, while many distinguished and experienced faculty teach at Hunter and the CUNY colleges, a significant number of new adjunct professors and graduate student fellows take charge of classes, particularly those at the introductory level.[3] Because I have chosen to present this paper as a case study, the collective "identity" of the institution is essential to my methodology. This paper finds its basis not in traditional research, but rather in the details of my experience teaching one multiply-disabled student. This pupil took three music classes with me when I was a graduate teaching fellow at Hunter College between 2003 and 2006.[4] I met Daniel Trush when he began attending Hunter as a non-matriculated student. Having learned some basic piano skills with his music therapist as part of his physical and cognitive rehabilitation, Daniel enrolled in my Music Fundamentals class. He subsequently took Ear Training I and a general voice performance class with me, and also took an elementary piano class and Music Appreciation with other instructors. Each of these courses presented different challenges for Daniel, his note-taker, his family-who attended each class with him-and for me. Although I had taught students with visual impairments and other physical disabilities in previous classes at Hunter, I had never yet encountered a student with a significant cognitive disadvantage. Daniel's presence in my classes inspired me to strive for greater clarity in my own teaching, and provided the opportunity for me to reevaluate my methods of assessment and mentoring.[5] As a rule, I ask students to fill out a questionnaire on the first day of class with basic information about their lives as students, but I also ask them to detail their musical lives and add some significant details about themselves that they think I ought to know. Being the academic packrat that I am, I managed to unearth Daniel's questionnaire from the first day of Music Fundamentals. He writes:I have a great interest in music and plan to take a number of music classes. I had a brain aneurism when I was 12 and was in a coma for many days. I never lost my love of music. Before my brain injury, I played the guitar for two years, and the trumpet for two years. Since my injury, I have played the keyboard with my right hand for the last three years.I learned later from his father, Ken Trush, that Daniel is a survivor of five brain aneurisms, one of which burst when he was twelve, leaving him hospitalized for a year. He used a wheelchair for two years following his injury, but Daniel has since learned to walk again using leg braces and he now has the full use of his right hand. When playing keyboard music, he can use the index finger of his left hand to deliver the bass line. …

I.L. Nascher, M.D. (1863-1944): The First American Geriatrician

Back to table of contents Previous article Next article History NotesFull AccessI.L. Nascher, M.D. (1863-1944): The First American GeriatricianLucy OzarinLucy OzarinSearch for more papers by this authorPublished Online:21 Nov 2008https://doi.org/10.1176/pn.43.22.0024Few psychiatrists know the name I.L. Nascher, M.D. Wrote Ewald Busse, M.D., and Dan Blazer, M.D., Ph.D., in their Textbook of Geriatric Psychiatry, published by American Psychiatric Publishing Inc., that Nascher is frequently considered the father of geriatrics and has been credited with coining the word“ geriatrics.”Ignatz Leo Nascher, M.D., coined the term“ geriatrics.”Credit: Courtesy of the NYU School of Medicine, Ehrman Medical Library ArchivesIn an article headlined “Geriatrics” in the New York Medical Journal in 1909, Nascher wrote that the word geriatrics is from the Greek word “geras, meaning old man, and iatrikos, relating to the [word] physician....” In Greek mythology, Geras is an old, shriveled man who represents the spirit of old age; his mother was Nyx, the so-called goddess of the night.So the term geriatrics means a physician who specializes in the medical care of individuals in old age—the opposite of the term“ pediatrics,” relating to the medical care of children.Senility “is a distinct period of life,” Nascher wrote,“ a physiological entity ... a period of life where degeneration and decay are natural and physiological.... [S]enility and its diseases should be considered apart from maturity and assigned to a separate place in medicine.”Ignatz Leo Nascher was born in Vienna, Austria, and was brought to the United States as an infant. His formal schooling in New York City led to a degree in pharmacy in 1882 and his M.D. in 1885 from the Department of Medicine of New York University.He entered medical practice in New York and served in the outpatient clinics of Mt. Sinai Hospital. Years later, in 1916, he took a position at the Department of Public Welfare, then at the Department of Hospitals. In 1931, at his request, he was put in charge of the 1,200-bed City Farm Colony on Roosevelt Island in Manhattan. That facility later became Goldwater Hospital and today is named Coler-Goldwater Memorial Hospital.He lectured on geriatrics at several medical schools in New York, Boston, and Chicago. He organized the New York Geriatric Society, though its existence was short-lived.In 1914 Nascher published a 500-page textbook, Geriatrics: The Diseases of Old Age and Their Treatment, which included physiological home and institutional care and medical-legal relations. A second edition was published in 1916. The book is said to be the first publication on geriatrics since the 1881 book by J.M. Charcot, M.D., and Alfred L. Loomis, M.D. titled Clinical Lectures on the Diseases of Old Age. An introduction to Nascher's book was written by Abraham Jacobi, M.D., president of the New York Academy of Medicine. Jacobi is credited with coining the word“ pediatrics” and establishing pediatrics as a separate medical discipline.Nascher's bibliography includes more than 70 titles (among them “The Senile State,” “Senile Debility,” and “The Senile Mentality”) published in various medical journals.In 1944 he read a paper on chronic brain syndrome at the annual meeting of the recently organized American Geriatric Society, which dedicated the meeting to Nascher and made him an honorary president.Nascher divided the span of life into three distinct periods: development, maturity, and senescence. His writings constantly emphasized that maturity and senility are different entities and that diseases of each phase require different treatment. Drugs reactions in maturity are different from those in old age, he said. He viewed old age as a period of degenerating and decaying cells and tissues, where the goal is not to cure disease as in maturity, but to return the old person to the previous physiological degenerating phase and retard death.“Senile degeneration is not a pathology and cannot be halted, though it may be retarded,” he wrote.He was aware of the social implications of aging and urged that old individuals be encouraged to feel young, maintain a good appearance and positive attitude, and keep occupied. “Courtship and marriage between an old person and one much younger ... will produce marked mental rejuvenation.”In the 1995 book Profiles in Gerontology: A Biographical Dictionary by W. Andrew Achenbaum, Ph.D., and D.M. Albert, the authors wrote that Nascher “was a prophet in every sense of the word.”▪ ISSUES NewArchived

Bedrock platforms within the Ross Embayment, West Antarctica: Hypotheses for ice sheet history, wave erosion, Cenozoic extension, and thermal subsidence

Ice‐penetrating radar (mostly airborne) and marine seismic surveys have revealed plateaus and terraces about 100–350 m below sea level beneath parts of the Ross Embayment, including the West Antarctic ice sheet, the Ross Ice Shelf, and the eastern Ross Sea. These surfaces cover many thousands of square kilometers and are separated by bedrock troughs occupied by the West Antarctic ice streams. Prominent plateaus are under Edward VII Peninsula, Siple Dome, and Roosevelt Island. Marine seismic data and gravity data over the buried plateaus support an interpretation that they were caused by erosion into basement. The flat and level nature of the surfaces that were formed by erosion, are near the same depth over large distances, and fringe the buried rugged bedrock topography of Marie Byrd Land supports an interpretation of marine rather than glacial erosion. Marine seismic reflection profiles over one of the plateau remnants show it as an angular unconformity cut into gently dipping sediments of late Oligocene age, draped with thin, flat‐lying sediments, implying that the plateau is early Miocene or younger. The younger limit for plateau erosion follows from the interpretation of the mechanism: erosion must predate permanent ice along the coast associated with the growth of the West Antarctic ice sheet, probably prior to 10 Ma and possibly prior to 14 Ma. The plateaus along the Siple Coast, with depths around 350 meters, do not rebound to close to sea level and wave base for models of removing past and present ice load. This discrepancy can be explained if Ross Embayment lithosphere has been cooling and subsiding since significant extension in Eocene to Oligocene time. Our interpretation requires crustal subsidence in the Ross Sea, which in turn implies higher bedrock elevations in the past within this region. Higher‐standing topography presented an opportunity for the accumulation of local ice sheets and caused sea level fluctuation prior to late Cenozoic time.

Dating ice flow change near the flow divide at Roosevelt Island, Antarctica, by using a thermomechanical model to predict radar stratigraphy

Radar‐detected internal layering contained in some ice divides shows upwarped arches termed Raymond bumps. The distribution of their amplitude with height can date the onset of divide flow, reflecting changes in the basin structure of the ice sheet. The distribution depends on rheology, surface geometry, accumulation rate, and temperature. Conway et al. (1999) used an isothermal parameterized ice flow model to estimate a date of 3200 years B.P., with no error estimate, for the onset of divide flow in Roosevelt Island, Ross Ice Shelf, which they associated with grounding line retreat of the West Antarctic Ice Sheet. No other retreat dating exists for an area of the Ross Ice Shelf distant from geological exposures. Employing a full thermomechanically coupled transient model, we use a direct search to determine which ice rheology best fits the observed bump distribution and surface profile, estimating the sensitivity of the dating to model parameters and exploring possible reasons for the observed asymmetry of the surface profile. Our main results are as follows: (1) A best estimate of the date of grounding line retreat near Roosevelt Island is 3000 years B.P., bounded by 2300 and 4200 years B.P. (2) Standard rheology (power n = 3) can only match the observed bump distribution for unrealistic isothermal models. (3) For thermomechanically coupled models a high power (n = 4) in Glen's law is required. (4) Low‐power rheologies and wind scouring cannot produce correct bump amplitude distributions. (5) Asymmetric accumulation cannot explain the observed asymmetry of the surface profile. (6) Modeling isochrones in flanking regions also indicates changes in flow around 3000 years B.P.

Parameter sensitivity studies for the ice flow of the Ross Ice Shelf, Antarctica

The diagnostic, dynamic/thermodynamic ice shelf model Finite Element Shallow Shelf Approximation Code (FESSACODE) is applied to the Ross Ice Shelf. We simulate the present ice flow which results from the ice thickness distribution, the inflow at the grounding line, and the surface and bottom temperatures and compare results with measured flow velocities. Our reference simulation reproduces the general flow pattern and the magnitudes of the flow velocities reasonably well. The ice flow is found to be very sensitive to the flow enhancement factor, the ice thickness, and the ice temperature but robust against inflow velocities from ice streams, glaciers, and ice rises. The ice rises (Roosevelt Island and Crary Ice Rise) stabilize the ice shelf by significantly decreasing the flow velocities for the entire ice shelf area. The ice shelf is susceptible to global warming in that a 2°C surface warming entails an increase of the flow velocities by a factor 1.25, whereas a 10°C warming leads to an increase by a factor 3.1.

A Pilgrim's Progress through the Angel Project

The car deposited me on the southern tip of Roosevelt Island near a crumbling gothic castle suffocated by ivy; it could have been Miss Havisham’s house but was in fact a smallpox hospital. This is where the Angel Project, the centerpiece of Lincoln Center Festival 2003, began. It was a suitably ghostly and serene beginning, just a tiny sidestep from normal New York life but one that took the audience into an unfamiliar, plaintive parallel city. Warner has done something like this before, in a derelict hotel in London in 1999 and in various buildings in Perth, Australia, a year later. Audience members become participants in a performance that uses all the city as a stage. Warner sketches a trail between abandoned buildings and intervenes in those empty, yet pregnant spaces to suggest a recent angelic presence. Occasionally visitors may encounter an angel directly. There were reports from Perth of solitary pilgrims taking 12 hours to complete the trail; along the way they were apparently provoked to contemplate their own divinity—or otherwise—and the fallen state of the city.

Continued northward expansion of the Ross Ice Shelf, Antarctica

The last major calving event along the Ross Ice Shelf (RIS, Antarctica) front occurred a decade ago, following a substantial increase in the rate of ice-front advance in the few years preceding the event. This “B-9” event, on the eastern part of the front between Edward VII Peninsula and Roosevelt Island, removed ≈ 5100 km2of ice, about 100 years of advance in that sector, but reduced the ice-shelf area by only 1%. Since 1987 the entire ice front has continued to advance, more than regaining the area lost during the B-9 event. The western front is now well north of any position recorded during the last 150 years, and it lias not experienced major calving forat least 90 years. Ice-front heights generally decrease from east to west, but local variability is high. Elevations are relatively low from 171° to 177° W, the location of “warm” Modified Circumpolar Deep Water circulation beneath the outer ice shelf. Modern heights considerably exceed historical heights between 179° Wand 178° E and are lower west of 174° E, probably due to recent dynamic changes such as rifting and the western advance. The general advance of the RIS front and the period of several decades to more than a century that elapses between major calving events is consistent with a relatively stable ice front. This contrasts with several smaller ice shelves along the Antarctic Peninsula and McMurdo Ice Shelf in the Ross Sea which have retreated substantially during the past few decades.

Detailed topography of Roosevelt Island and Siple Dome, West Antarctica

Detailed surface topography is presented for two dome features of the West Antarctic ice sheet, Siple Dome and Roosevelt Island. Both these domes show linear topographic features, or “scars”, on [heir flanks. Topography is determined from a combination of existing digital elevation models (DEMs; based on satellite radar altimctry), photoclinomctry (using advanced very high-resolution radiometer images to quantitatively infer topographic details) and, in the case of Siple Dome, surface global positioning system topographic profiles. The enhanced DEMs provide heights and shapes for a variety of surface features in the vicinity of the domes, such as scars, surface undulations, ice rises and the domes themselves. The DEMs indicate that the scar features on both domes are high relative to adjacent rapid-ice-llow areas. Scars and other related morphologic features on the flanks of both domes can be interpreted as former active ice streams and stream margins. For Siple Dome, this interpretation is confirmed by radar profiling. The evolution of the topographic height of the scars is a combination of two processes: initial elevation rise due to a positive mass balance at the shear margin in the immediate aftermath of shut-down of the ice stream; and later downslope flow as the scars become part of the dome and the dome surface velocity field. Superimposed on these events is accumulation, which buries the original shear margin but elevates the scar surface expression. Depending upon the timing of shut-flown, and the relative magnitude of these processes, the height of the scars above the current rapidly flowing surfaces may be indicative of ice-sheet thinning since shut-down, or dome expansion across former ice-stream trunks in a more or less steady-state ice sheet.

Seasonal circulation under the eastern Ross Ice Shelf, Antarctica

An annual cycle of shelf water temperatures and salinities measured at depth near the eastern Ross Ice Shelf front is used to force a two‐dimensional thermohaline circulation model adapted to different subice paths in the vicinity of Roosevelt Island. These paths were assumed to have constant water column thicknesses of 160, 200, and 240 m and lengths of 460–800 km. Additional simulations with the longer cavity included a 80‐m thick interior water column in order to approximate conditions closer to the grounding line. Model results were compared with other long‐term measurements that showed outflow from beneath the ice shelf. Shelf water flowing into the cavity west of Roosevelt Island appears to follow a cyclonic route around the island. The ice shelf base loses mass at a rate of 18–27 cm yr−1, with seasonal forcing increasing the spatial and temporal variability of circulation and property distributions in the larger cavities. Shallow cavities reduce the influence of shelf water variability with increasing length. Introducing a transient shelf water temperature rise of 0.01°C yr−1 for 100 years increases the melt rate by 4–5 times. However, this increase is smaller if salinity also decreases over the same period of time, as might be expected from the added meltwater component.

Excavation of the Roosevelt Island valve chamber, New York City : Proc 1987 Rapid Excavation and Tunnelling Conference, New Orleans, 14–17 June 1987 V2, P881–898. Publ Littleton: Society of Mining Engineers, 1987

Excavation of the Roosevelt Island valve chamber, New York City : Proc 1987 Rapid Excavation and Tunnelling Conference, New Orleans, 14–17 June 1987 V2, P881–898. Publ Littleton: Society of Mining Engineers, 1987

Effect of age on thyroid hormone physiology and function.

Journal of the American Geriatrics SocietyVolume 33, Issue 5 p. 360-365 Effect of Age on Thyroid Hormone Physiology and Function Dr. Steven R. Gambert MD, FAGS, Corresponding Author Dr. Steven R. Gambert MD, FAGS Director Professor of Medicine and Director, Center for Aging and Adult Development, New York Medical College, Valhalla, New York Dr. Gambert is a recipient of the Geriatric Medicine Academic Award from the National Institute On Aging, NIH Grant No. 1 KO7 AG00250-01.Center for Aging and Adult Development, New York Medical College, Valhalla, NY 10595.Search for more papers by this authorPanayiotis D. Tsitouras MD, Panayiotis D. Tsitouras MD Associate Professor of Medicine, New York Medical College; Director of Medicine and Gerontology, Coler Memorial Hospital, Roosevelt Island, New YorkSearch for more papers by this author Dr. Steven R. Gambert MD, FAGS, Corresponding Author Dr. Steven R. Gambert MD, FAGS Director Professor of Medicine and Director, Center for Aging and Adult Development, New York Medical College, Valhalla, New York Dr. Gambert is a recipient of the Geriatric Medicine Academic Award from the National Institute On Aging, NIH Grant No. 1 KO7 AG00250-01.Center for Aging and Adult Development, New York Medical College, Valhalla, NY 10595.Search for more papers by this authorPanayiotis D. Tsitouras MD, Panayiotis D. Tsitouras MD Associate Professor of Medicine, New York Medical College; Director of Medicine and Gerontology, Coler Memorial Hospital, Roosevelt Island, New YorkSearch for more papers by this author First published: May 1985 https://doi.org/10.1111/j.1532-5415.1985.tb07137.xCitations: 10 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume33, Issue5May 1985Pages 360-365 RelatedInformation

Distribution and provenance of recycled palynomorphs in surficial sediments of the Ross Sea, Antarctica

Quantitative analysis of surficial sediments in the Ross Sea has shown that the highest densities of recycled palynomorphs occur in a region in the southeast, immediately north of the Ross Ice Shelf in the vicinity of Roosevelt Island. There, spores and pollen of Late Cretaceous to Early Tertiary age predominate. Eocene dinoflagellates and rare Palaeozoic spores are also present. In the western half of the Ross Sea, densities of recycled palynomorphs are lower, but relative frequencies of Palaeozoic types are higher. On the continental shelf, the palynomorphs have been recovered, in equal abundance, from sediments identified as basal tills and compound glaci-marine sediments. Comparison of the observed patterns of distribution with patterns of ice flow in the Ross Ice Shelf shows a clear correlation between the high palynomorph densities in the southeastern Ross Sea and discharge from ice streams D and E. Geophysical information from aeromagnetic and radio-echo sounding surveys in the catchment areas of these ice streams suggests the most likely source for the recycled palynomorphs to be in a region of subdued topography inland of the present grounding line in the Marie Byrd Land sector of the Ross Ice Shelf, extending probably not further east than 130°W. This region probably represents a continuation of the easternmost Ross Sea Basin. The presence of marine Eocene sediments there, attested to by dinoflagellates in the recycled assemblages, accords with suggestions of a late Mesozoic—Cenozoic opening of the Ross Sea. The observed patterns of palynomorph distribution reflect input from ice drainage areas in both East and West Antarctica. The preservation of sediments of differing provenance in distinct areas on the sea floor probably indicates processes of meltout of debris near the grounding line of the Ross Ice Shelf during past phases of expansion. Marine bottom currents have not significantly redistributed the recycled microfossils.

Field Studies of Bottom Crevasses in the Ross Ice Shelf, Antarctica

AbstractSurface and airborne radar sounding data were used to identify and map fields of bottom crevasses on the Ross Ice Shelf. Two major concentrations of crevasses were found, one along the grid-eastern grounding line and another, made up of eight smaller sites, grid west of Crary Ice Rise. Based upon an analysis of bottom crevasse heights and locations, and of the strength of radar waves diffracted from the apex and bottom corners of the crevasses, we conclude that the crevasses are formed at discrete locations on the ice shelf. By comparing the locations of crevasse formation with ice thickness and bottom topography, we conclude that most of the crevasse sites are associated with ice rises. Hence we have postulated that six ice rises, in addition to Crary Ice Rise and Roosevelt Island, exist in the grid-western sector of the ice shelf. These “pinning points” may be important for interpreting the dynamics of the West Antarctic ice sheet.

Field Studies of Bottom Crevasses in the Ross Ice Shelf, Antarctica

AbstractSurface and airborne radar sounding data were used to identify and map fields of bottom crevasses on the Ross Ice Shelf. Two major concentrations of crevasses were found, one along the grid-eastern grounding line and another, made up of eight smaller sites, grid west of Crary Ice Rise. Based upon an analysis of bottom crevasse heights and locations, and of the strength of radar waves diffracted from the apex and bottom corners of the crevasses, we conclude that the crevasses are formed at discrete locations on the ice shelf. By comparing the locations of crevasse formation with ice thickness and bottom topography, we conclude that most of the crevasse sites are associated with ice rises. Hence we have postulated that six ice rises, in addition to Crary Ice Rise and Roosevelt Island, exist in the grid-western sector of the ice shelf. These “pinning points” may be important for interpreting the dynamics of the West Antarctic ice sheet.

Field Studies of Bottom Crevasses in the Ross Ice Shelf, Antarctica (Abstract only)

Surface and airborne radar sounding data were used to identify and map fields of bottom crevasses on the Ross Ice Shelf. Two major concentrations of crevasses were found, one along the grid-eastern grounding line and another, made up of eight smaller sites, grid-west of Crary Ice Rise.Based upon an analysis of bottom crevasse heights and locations, and of the strength of radar waves diffracted from the apex and bottom corners of the gridcrevasses, we conclude that the crevasses are formed at discrete locations on the ice shelf. By comparing the locations of crevasse formation with ice thickness and bottom topography, we conclude that most of the crevasse sites are associated with grounding. Hence we have postulated that six grounded areas, in addition to Crary Ice Rise and Roosevelt Island, exist in the grid-western sector of the ice shelf. These pinning points may be important for interpreting the dynamics of the West Antarctic ice sheet.

Field Studies of Bottom Crevasses in the Ross Ice Shelf, Antarctica (Abstract only)

Surface and airborne radar sounding data were used to identify and map fields of bottom crevasses on the Ross Ice Shelf. Two major concentrations of crevasses were found, one along the grid-eastern grounding line and another, made up of eight smaller sites, grid-west of Crary Ice Rise. Based upon an analysis of bottom crevasse heights and locations, and of the strength of radar waves diffracted from the apex and bottom corners of the gridcrevasses, we conclude that the crevasses are formed at discrete locations on the ice shelf. By comparing the locations of crevasse formation with ice thickness and bottom topography, we conclude that most of the crevasse sites are associated with grounding. Hence we have postulated that six grounded areas, in addition to Crary Ice Rise and Roosevelt Island, exist in the grid-western sector of the ice shelf. These pinning points may be important for interpreting the dynamics of the West Antarctic ice sheet.