International Symposium on Radioglaciology and Immediate Past President: E.M
Total Page：16
File Type：pdf, Size：1020Kb
Load more
Recommended publications
-
Dustin M. Schroeder
Dustin M. Schroeder Assistant Professor of Geophysics Department of Geophysics, School of Earth, Energy, and Environmental Sciences 397 Panama Mall, Mitchell Building 361, Stanford University, Stanford, CA 94305 [email protected], 440.567.8343 EDUCATION 2014 Jackson School of Geosciences, University of Texas, Austin, TX Doctor of Philosophy (Ph.D.) in Geophysics 2007 Bucknell University, Lewisburg, PA Bachelor of Science in Electrical Engineering (B.S.E.E.), departmental honors, magna cum laude Bachelor of Arts (B.A.) in Physics, magna cum laude, minors in Mathematics and Philosophy PROFESSIONAL EXPERIENCE 2016 – present Assistant Professor of Geophysics, Stanford University 2017 – present Assistant Professor (by courtesy) of Electrical Engineering, Stanford University 2020 – present Center Fellow (by courtesy), Stanford Woods Institute for the Environment 2020 – present Faculty Affiliate, Stanford Institute for Human-Centered Artificial Intelligence 2021 – present Senior Member, Kavli Institute for Particle Astrophysics and Cosmology 2016 – 2020 Faculty Affiliate, Stanford Woods Institute for the Environment 2014 – 2016 Radar Systems Engineer, Jet Propulsion Laboratory, California Institute of Technology 2012 Graduate Researcher, Applied Physics Laboratory, Johns Hopkins University 2008 – 2014 Graduate Researcher, University of Texas Institute for Geophysics 2007 – 2008 Platform Hardware Engineer, Freescale Semiconductor SELECTED AWARDS 2021 Symposium Prize Paper Award, IEEE Geoscience and Remote Sensing Society 2020 Excellence in Teaching Award, Stanford School of Earth, Energy, and Environmental Sciences 2019 Senior Member, Institute of Electrical and Electronics Engineers 2018 CAREER Award, National Science Foundation 2018 LInC Fellow, Woods Institute, Stanford University 2016 Frederick E. Terman Fellow, Stanford University 2015 JPL Team Award, Europa Mission Instrument Proposal 2014 Best Graduate Student Paper, Jackson School of Geosciences 2014 National Science Olympiad Heart of Gold Award for Service to Science Education 2013 Best Ph.D. -
Mass Balance of East Antarctic Glaciers and Ice Shelves from Satellite Data
Annals of Glaciology 34 2002 # InternationalGlaciological Society Massbalance ofEast Antarctic glaciers and ice shelves fromsatellite data Eric Rignot JetPropulsion Laboratory,California Institute ofTechnology,4800OakGrove Drive,Pasadena, CA9 1109-8099,U.S.A. ABSTRACT.Thevelocity and mass dischargeof nine ma jorEast Antarcticglaciers not draininginto the Ross orFilchner^R onneI ce Shelvesis investigatedusing interferometric synthetic aperture radar(InSAR) datafrom the EuropeanR emote-sensing Satellite1and2 (ERS-1/2)andRAD ARSAT-1.Theglaciers are: David, Ninnis, Mertz,Totten,Scott, Denman, Lambert, Shiraseand Stancom b-Wills. InSARis used tolocate their groundingline with pre- cision.Ice velocityis measured witheither InSARor aspeckle-trackingtechnique. Ice thickness is deducedfrom prior -determined ice-shelf elevationassuming hydrostatic equi- librium.Mass fluxesare calculated both at the groundingline and at a fluxgate located downstream.The grounding-line flux is comparedto a mass inputcalculated from snow accumulationto deduce the glaciermass balance.The calculation is repeatedat the flux gatedownstream of the groundingline to estimate the averagebottom melt rate ofthe ice shelf understeady-state conditions.The main results are:( 1)Groundinglines arefound severaltens ofkm upstream ofprior-identified positions, not because of a recent ice-sheet retreat butbecause of the inadequacyof prior-determined grounding-linepositions. ( 2)No grossim balancebetween outflow and inflow is detected onthe nineglaciers being investi- gated,with an uncertainty of 10^20%.Prior-determined, largelypositive mass imbalances weredue to an incorrect localizationof the groundingline. ( 3)High rates ofbottommelting (24 7 m ice a^1)areinferred neargrounding zones, where ice reaches the deepest draft.A few§glaciers exhibit lower bottom melt rates (4 7 m ice a^1).Bottommelting, however , appearsto be a majorsource ofmass loss onAntarctic § ice shelves. -
Profile of Eric Rignot PROFILE Brian Doctrow, Science Writer
PROFILE Profile of Eric Rignot PROFILE Brian Doctrow, Science Writer Sometimes taking a step back helps to see things more clearly. Eric Rignot, a glaciologist at the Univer- sity of California, Irvine, has found that when studying the behavior of glaciers and ice sheets, it helps to take a giant step back, all of the way into space. His use of satellite radar imaging has provided extraordinarily detailed information about how fast the ice sheets are melting and how much they contribute to sea-level rise. Rignot’s findings have shown the impact of cli- mate change on the ice sheets and how little time there may be to stop it. His work has earned him nu- merous honors, including fellowship in the American Geophysical Union in 2013 and membership in the National Academy of Sciences in 2018. Finding His Calling Eric Rignot grew up in what he describes as a rugged part of the French countryside, near the city of St. Etienne. Rignot partly attributes his interest in polar environments to the rough winter weather he experi- enced growing up. As a child, he enjoyed reading novels about polar adventures. He also recalls reading about Nobel Prize winners in an encyclopedia as a kid, which exposed him to the explosion of scientific knowledge that emerged in the early 20th century. Eric Rignot. Image credit: Ian Fenty (NASA/JPL-Caltech, Pasadena, CA). This kindled a lifelong fascination with science and the natural world. to realize the value of having an education with a broad As a student, Rignot pursued studies in mathe- foundation, because it gave him the flexibility to branch matics, in part because in the French educational out into new fields. -
Observing Antarctic Glaciers
Observing Antarctic glaciers Eric Rignot Dept. Earth System Science University of California Irvine & Caltech’s Jet Propulsion Laboratory Pasadena CA “The Antarctic ice sheet is likely to gain mass because of enhanced precipitation, while the Greenland ice sheet is likely to lose mass because the increase in runoff will exceed the precipitation increase.” IPCC 2001. MWP1a: SLR > 40 mm/yr Alley et al. 2005 P ~ 24 cm/yr SLR ~7 m Annual TO ~ 510 Gt/yr or 1.4 mm/yr SLR P ~ 17 cm/yr 1.5 xUSA SLR ~ 60 m7 xGrIS Annual TO ~ 2,500 Gt/yr or 6 mm/yr SLR Ice sheet mass balance techniques Radar/Laser Altimetry Time-variable gravity Perimeter flux vs snow accumulation Davis et al., 2005 Velicogna and Wahr, 2006 Rignot and Thomas, 2002 Height change: Time-variable gravity: SMB – Discharge 1992-2012 ERS + Envisat SRA 2002-present (GRACE) 1957/1975 IGY-Landsat 2003-2008 ICESat 1992-present (InSAR-RACMO) 2009-2016 OIB GRACE follow-on 2017? 2010-present Cryosat Sentinel-1 2014; DESDynI 2020 2016 ICESat-2; 2016 Sentinel-2 ALOS-2 2014 Satellite Radar Altimetry: 1992 Wingham et al., 1998 Shepherd et al., 2001 Laser altimetry over ice sheets: 2003 Pritchard et al., 2012 Pritchard et al., 2011 SAR Interferometry Goldstein et al., 1993 Grounding lines Rignot et al., 2011 Rignot, 1998 Collapse of Larsen A: 1995 Rott et al., 2002 Acceleration of major Antarctic glaciers Rignot et al., 2002 Amundsen Bay Embayment collapse: 1996‐2008 2008‐1996 Glacier response to ice shelf collapse De Angelis and Svarka, 2003. Rignot et al. -
Ice News Bulletin of the International
ISSN 0019–1043 Ice News Bulletin of the International Glaciological Society Number 172 3rd Issue 2016 Contents 2 From the Editor 18 Presentation of Honorary Membership to 4 Blog: New Chief Editor for the Professor Keiji Higuchi International Glaciological Society 19 New office for the IGS 5 International Glaciological Society 20 Second Circular: International Symposium 5 Journal of Glaciology on Polar Ice, Polar Climate, Polar Change, 7 Creative Commons licensing Boulder, CO, USA, August 2017 8 Report on the IGS Symposium La Jolla, CA, 32 First Circular: International Symposium on July 2016 Cryosphere and Biosphere, Kyoto, Japan, 13 Report on the British Branch Meeting, March 2018 Southampton, September 2016 36 Glaciological diary 15 News 39 New members 15 Report from the Summer School, McCarthy, Alaska, June 2016 Cover picture: Glacier de Gébroulaz, Vanoise, France, August 2015. Measurements of flow velocity, thickness variation and mass balance are taken several times a year on this glacier by Glacioclim (Laboratoire de Glaciologie et Géophysique de l’Environnement, Grenoble, France). Photo by Coline Bouchayer. EXCLUSION CLAUSE. While care is taken to provide accurate accounts and information in this Newsletter, neither the editor nor the International Glaciological Society undertakes any liability for omissions or errors. 1 From the Editor Dear IGS member Welcome to the third and last issue of ICE breaks (as opposed to running across the for 2016. In this editorial I would like to street looking for a Starbucks and once discuss IGS symposia and in particular our there waiting in line for half an hour) so registration fees. We are regularly criticized this is an excellent opportunity to grab the for setting the registration fees too high and speakers from the previous session and told that people will be unable to attend discuss their presentations. -
Non-Gaussian Statistical Analysis of Polarimetric Synthetic Aperture Radar Images
FACULTY OF SCIENCE AND TECHNOLOGY DEPARTMENT OF PHYSICS AND TECHNOLOGY Non-Gaussian Statistical Analysis of Polarimetric Synthetic Aperture Radar Images Anthony Paul Doulgeris A dissertation for the degree of Philosophiae Doctor February 2011 Abstract This thesis describes general methods to analyse polarimetric synthetic aperture radar images. The primary application is for unsupervised image segmentation, and fast, practical methods are sought. The fundamental assumptions and statistical modelling are derived from the phys- ics of electromagnetic scattering from distributed targets. The physical basis directly leads to the image phenomenon called speckle, which is shown to be potentially non- Gaussian and several statistical distributions are investigated. Speckle non-Gaussianity and polarimetry both hold pertinent information about the target medium and methods that utilise both attributes are developed. Two distinct approaches are proposed: a local feature extraction method; and a model-based clustering algorithm. The local feature extraction approach creates a new six-dimensional description of the image that may be used for subsequent image analysis or for physical parameter extraction (inversion). It essentially extends standard polarimetric features with the addition of a non-Gaussianity measure for texture. Importantly, the non-Gaussianity measure is model independent and therefore does not unduly constrain the analysis. Unsupervised image segmentation is demonstrated with good results. The model-based approach describes a Bayesian clustering algorithm for the K- Wishart model, with fast moment based parameter estimation, and incorporates both non-Gaussianity and polarimetry. The initial implementation requires the number of classes, and initial segmentation, and the effective number of looks (an important model parameter) to be given in advance. -
Five Decades of Radioglaciology
Annals of Glaciology Five decades of radioglaciology Dustin M. Schroeder1,2, Robert G. Bingham3, Donald D. Blankenship4, Knut Christianson5, Olaf Eisen6,7 , Gwenn E. Flowers8 , Nanna B. Karlsson9 , Michelle R. Koutnik5, John D. Paden10 and Martin J. Siegert11 Article 1Department of Geophysics, Stanford University, Stanford, USA; 2Department of Electrical Engineering, Stanford University, Stanford, USA; 3School of GeoSciences,University of Edinburgh, Edinburgh, UK; 4Institute for Cite this article: Schroeder DM et al. (2020). Geophysics, University of Texas, Austin, USA; 5Department of Earth and Space Sciences, University of Washington, Five decades of radioglaciology. Annals of 6 Glaciology 61(81), 1–13. https://doi.org/ Seattle, USA; Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 7 8 10.1017/aog.2020.11 Germany; University of Bremen, Bremen, Germany; Department of Earth Sciences, Simon Fraser University, Vancouver, Canada; 9Geological Survey of Denmark and Greenland, Copenhagen, Denmark; 10Center for the Received: 2 December 2019 Remote Sensing of Ice Sheets, University of Kansas, Lawrence, USA and 11Grantham Institute, and Department Revised: 11 February 2020 of Earth Science and Engineering, Imperial College London, London, UK Accepted: 11 February 2020 First published online: 9 March 2020 Abstract Keywords: Radar sounding is a powerful geophysical approach for characterizing the subsurface conditions glaciological instruments and methods; ground-penetrating radar; radio-echo of terrestrial and planetary ice masses at local to global scales. As a result, a wide array of orbital, sounding; remote sensing airborne, ground-based, and in situ instruments, platforms and data analysis approaches for radioglaciology have been developed, applied or proposed. Terrestrially, airborne radar sounding Author for correspondence: has been used in glaciology to observe ice thickness, basal topography and englacial layers for five Dustin M. -
Krista Marie Soderlund the University of Texas at Austin Institute for Geophysics, John A
Krista Marie Soderlund The University of Texas at Austin Institute for Geophysics, John A. & Katherine G. Jackson School of Geosciences J.J. Pickle Research Campus, Bldg. 196 (ROC), 10100 Burnet Rd. (R2200), Austin, TX 78758-4445 [email protected], Office: 512-471-0449, Cell: 218-349-3006, FAX: 512-471-8844 Research Interests Geophysical Fluid Dynamics, Magnetohydrodynamics, Planetary Science, Cryosphere Education University of California, Los Angeles Ph.D., Geophysics and Space Physics, 2011 M.S., Geophysics and Space Physics, 2009 Florida Institute of Technology B.S., Double major in Physics & Space Science, 2005, Summa Cum Laude Employment University of Texas at Austin, Institute for Geophysics Research Associate, September 2014-Present UTIG Postdoctoral Fellow, October 2011-September 2014 University of California, Los Angeles, Department of Earth and Space Sciences Graduate Student Researcher, Advisor: Dr. Jonathan M. Aurnou, 2006-2011 California Institute of Technology, Division of Geological and Planetary Sciences Summer Undergraduate Research Fellow, Dr. Joann M. Stock, 2005 NASA Jet Propulsion Laboratory, CA Consultant, Dr. Bonnie J. Buratti, 2006 Planetary Geology & Geophysics Undergrad Research Program, Dr. B.J. Buratti, 2004 Florida Institute of Technology, Department of Physics and Space Science Undergraduate Researcher, Dr. Niescja E. Turner, 2004-2005 Naval Oceanographic Office, Hydrology Code, Stennis Space Center, MS Physical science aid, 2003 Mission Experience Saturn Probe Interior and aTmosphere Explorer (SPRITE) -
Chapter 16 Glaciers As Landforms: Glaciology
Chapter 16 j Glaciers as Landforms: Glaciology Of all thewater near the surface of the earth, only about by the rheidity of ice (p. 13), important differences are 2 percent is on the land, in the solid state as glacier ice to be noted whether flow is confined or unconfined. (Figure 2-5). Even this small fraction is sufficient to Glaciers originate in regions where snow accumu cover entirely one continent (Antarctica) and most of lation exceeds loss, and they flow outward or down the largest island (Greenland) with ice to an average ward to regions where losses exceed accumulation thickness of 2.2 km over Antarctica and 1.5 km over (Figure 16-2). The terminus, or downglacier extremity, Greenland. At the present time, about 10 percent of the represents the line where losses by all causes (melting, earth's land area is ice covered. An additional 20 per sublimation, erosion, and calving into water: collec cent has been ice covered repeatedly during the glacia tively termed ablation) equal the rate at which ice can tions of the Pleistocene Epoch, much of it as recently as be supplied by accumulation and forward motion. 15,000 to 20,000 years ago. Glaciation has been the Some valley glaciers have steep ice faces at their ter dominant factor in shaping the present landscape of mini, but others end deeply buried in transported rock North America northward of the Ohio and Missouri debris, so that the exact location of the terminus is rivers and of Eurasia northward of a line from Dublin uncertain. -
Evidence for Possible New Subglacial Lakes Along a Radar Transect Crossing the Belgica Highlands and the Concordia Trench
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Earth-prints Repository Terra Antartica Reports 2008, 14, 000-000 (4 pp - 2 colour p) Evidence for Possible New Subglacial Lakes along a Radar Transect Crossing the Belgica Highlands and the Concordia Trench A. FORIERI1*, I.E. TABACCO1, L. CAFARELLA2, S. URBINI2, C. BIANCHI2, A. ZIRIZZOTTI2 1Università degli Studi di Milano, Sez. Geofi sica, Via Cicognara 7, 20129 Milano - Italia 2Istituto Nazionale Geofi sica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma - Italia *Corresponding author ([email protected]) INTRODUCTION Subglacial lakes are of great interest to the scientifi c community, and more than 140 lakes have been identifi ed in Antarctica and catalogued (Siegert et al., 2005, Cafarella et al., 2006). We report on the possible existence of 5 new subglacial lakes in the area between the Belgica HighLands and the Concordia Trench. Analysis of radar data collected during the 2003 Antarctic fi eld survey reveals particularly strong radar echoes coming from the subglacial interface. As radar surveys are only one of the methods used to identify subglacial lakes, the presence of these 5 new lakes must be discussed and confi rmed through other geophysical investigations. DATA COLLECTION AND PROCESSING During the Italian Antarctic fi eld survey in 2003, airborne radar measurements were made around Dome C (Fig. 1) to better defi ne geological structures such as the Concordia and Aurora trenches and the Concordia, Aurora and Vincennes subglacial lakes (Forieri et al., 2004). Data were collected with a radar system operating at 60 MHz frequency and acquiring 10 traces s-1 with a pulse length of 1 μs. -
Instruments and Methods an Improved Coherent Radar Depth Sounder
Journal of Glaciology, Vol. 44, No. 148, 1998 Instruments and Methods An improved coherent radar depth sounder 2 3 1 S. GoGINENI,1 T. CHUAH, C. ALLEN,1 K. jEZEK, R. K. MooRE 1Radar Systems and Remote Sensing Laboratory, The University of Kansas, 2291 Irving Hill Road, Lawrence, Kansas 66045-2969, US.A. 2Silicon Wireless, 2025 Garcia Avenue, Mountain View, California 94043, US.A. 3 Byrd Polar Research Center, The Ohio State University, 108 Scott Hall, 1090 Carmack Road, Columbus, Ohio 43210-1002, US.A. ABSTRACT. The University of Kansas developed a coherent radar depth sounder during the 1980s. This system was originally developed for glacial ice-thickness measure- ments in the Antarctic. During the field tests in the Antarctic and Greenland, we found the system performance to be less than optimum. The field tests in Greenland were per- formed in 1993, as a part of the NASA Program for Arctic Climate Assessment ( PARCA ). We redesigned and rebuilt this system to improve the performance. The radar uses pulse compression and coherent signal processing to obtain high sensi- tivity and fine along-track resolution. It operates at a center frequency of 150 MHz with a radio frequency bandwidth of about 17 MHz, which gives a range resolution of about 5 m in ice. We have been operating it from a NASA P-3 aircraft for collecting ice-thickness data in conjunction with laser surface-elevation measurements over the Greenland ice sheet during the last 4 years. We have demonstrated that this radar can measure the thick- ness of more than 3 km of cold ice and can obtain ice-thickness information over outlet glaciers and ice margins. -
Basal Conditions at the Grounding Zone of Whillans Ice Stream, 10.1002/2015JF003806 West Antarctica, from Ice-Penetrating Radar
Journal of Geophysical Research: Earth Surface RESEARCH ARTICLE Basal conditions at the grounding zone of Whillans Ice Stream, 10.1002/2015JF003806 West Antarctica, from ice-penetrating radar Key Points: 1 2 3 4 4 • Radar basal reflectivity in a grounding Knut Christianson , Robert W. Jacobel , Huw J. Horgan , Richard B. Alley , Sridhar Anandakrishnan , zone embayment is lower than David M. Holland5, and Kevin J. DallaSanta5 that expected from an ice-seawater interface 1Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA, 2Physics Department, • Radar amplitude and waveform Saint Olaf College, Northfield, Minnesota, USA, 3Antarctic Research Centre, Victoria University of Wellington, Wellington, modeling suggests that basal 4 reflectivity is reduced by entrained New Zealand, Department of Geosciences and Earth and Environmental Systems Institute, Pennsylvania State University, sediment and basal roughness University Park, Pennsylvania, USA, 5Courant Institute of Mathematical Sciences, New York University, New York, • A reflectivity increase downflow of New York, USA the grounding line suggests that sediment deposition in grounding zones occurs via basal debris melt-out Abstract We present a comprehensive ice-penetrating radar survey of a subglacial embayment and adjacent peninsula along the grounding zone of Whillans Ice Stream, West Antarctica. Through basal Correspondence to: waveform and reflectivity analysis, we identify four distinct basal interfaces: (1) an ice-water-saturated till K. Christianson, [email protected] interface inland of grounding; (2) a complex interface in the grounding zone with variations in reflectivity and waveforms caused by reflections from fluting, sediment deposits, and crevasses; (3) an interface of anomalously low-reflectivity downstream of grounding in unambiguously floating areas of the embayment Citation: Christianson, K., R.