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Visit the follow-on project web page here Page Contents:
Project Summary Page from original NSF proposalCollaborative Proposal with University of Washington and University of Texas: WAISCORE Site Selection
The U.S. ice core research community's WAISCORES
project calls for an ice core to be drilled from the inland flow divide
region of the West Antarctic Ice Sheet. The ice core program at the
inland site is in the planning stage; site-selection surveys have begun, but
a specific site still needs to be identified. We propose to contribute to
the inland site selection process by: The work we propose to carry out is one component of the site selection process. We will focus on finding sites where the climate record should be best preserved throughout its long ice dynamics history. Based on existing radar data and ice dynamical models, we will search for sites that optimize age resolution, and avoid potentially disturbed basal ice. We will work closely with members of the U.S. Ice Core Working Group and University of New Hampshire (UNH) who are identifying areas with good depositional environments and firn preservation, and with this combined approach we expect to identify the optimal site or sites meeting all the criteria for a high quality paleoclimate record. The proposed project is a collaboration between members at University of Texas Institute for Geophysics (UTIG) and University of Washington Geophysics program (UW). D. Morse will be primarily responsible for carrying out this project while on a post-doctoral appointment at UTIG. Radar data processing will be done at UTIG utilizing the expertise and resources assembled by D. Blankenship. Ice flow calculations will be performed at both UTIG and UW through collaboration between D. Morse and E. Waddington. Our schedule will be structured by seasons. During summers we will employ undergraduate-level personnel to pick internal layers from the radar data. We anticipate two summers of picking will be required to complete the internal layer data set. With some internal layer data in hand, we will begin flow modeling during the winter of 1997/98. Over the winter of 1998/99, we will complete the flow modeling survey and present our core site recommendations to the WAISCORES community. Project Status, 10/97: Presentation to Ice Core working group concerning FS97/98 AWS installations First, a review. The topic of site selction
came up at the Ice Core Working Group (ICWG) meeting held in conjunction
with the September 1997 WAIS meeting. Specifically, the long-range
plans calls for Chuck Stearns to intall a network of AWS units in the
vicinity of the inland coring site. If all goes well, Stearns may be
able to install the first of these stations during the next (1997/98) field
season. The question is, "where should it go?" Optimally, this
station would be installed at the location where the core is ultimately to
be drilled. This would give the longest instrumental record climate
record that is directly comparable to the core proxy record. This is a fine
goal but is perhaps unachievable at this point. Fom the perspective of this
particular project, a review of the radar transects and calculation of
timescales has not been completed, so to make a final site determination now
would be premature. Nevertheless, an AWS site needs to be selected.
Perhaps an alternative goal should be to select a site that has a climate
likely to be characteristic of as large a region as possible. To this
end, we present some preliminary data that we will ultimately use to support
our modelling efforts. Figure 1 is an overview of the West Antarctic Ice Sheet. In this figure, the coast lines and surface features, shown as black lines, were digitized from the SPRI folio. The dashed lines show the main ice flow divides. The surface elevation contour interval is 500 meters. The colored patch shows the region of CASERTZ/WAIS data coverage. This 222x222 km area was surveyed along transects covering a square grid at 5.3 km line spacing. Surface features within this region are shown in white. The ice surface elevation is contoured at 50 m, and bedrock elevations at 500 meter intervals. The scattered red and green dots in this figure show the locations of (some of the) accumulation rate measurements in the vicinity.
The morphology of the inland divide region is shown more clearly in Figure 2. The spine of the surface topographic ridge which separates ice flow into the Ross embayment (image down) and the Pine Island embayment (image up) is shown by the white, dashed line. A prominent dome exists along the ridge centered at about 115oW 79oS. This feature, which was not identified on the SPRI folio, rises more than 50 meters above the surrounding ridge. Shallow firn cores were collected at the three red accumulation rate sites shown, the northern-most of these was earlier identified as a likely coresite candidate based on a visual examination of airborne radar profiles. This site will be referred to as "RIDS95A". The surface topography is largely controlled by bed features. These new data show that the "sinuous ridge" identified in the SPRI folio is in fact bisected by a trench that connects to the Bentley Subglacial Trench (image down right). The saddle west of the prominent dome overlies this trench, while the dome itself overlies the mountainous terrain adjacent to this trench. In general, the base of the mountains is at -1000 to -1500 meters; the bed is rugged in regions above approximately -1000 meters, whereas the bed is smooth in regions with topography below about -1500 meters. For the purpose of initiating discussion on locating
the first of the AWS sites, I have identified four "straw-man" candidates.
These are (A) the large dome, (B) the saddle, (C) the small dome, and (D)
the "RIDS95A" site. Some of their merits are presented
below. So how about it folks, where should we put this station? [Meteorologists, your input especially is urgently needed now]. - D. Morse 11/97 March 1999 MGM/ITASE/ICWG presentation graphicsFor all of you who were there, and those of you who weren't, here are some splashy graphics that I showed at these meetings. They include attribution for us, UTIG, and NSF. I'd be happy for anyone to use them to assist in their work and for their presentations. I'd appreciate hearing about it if anyone does grab a copy of these and uses them. - D. Morse 3/99
Site assessment for WAISCORES planning documentThe WAISCORES Science and Implementation Plan endorsed by the U.S. Ice Core Working Group in June, 2000, presented a discussion on site selection activities. For the purpose of that discussion, we identified two example sites, "North" and "South", that are ice thickness end-menbers for the extremes likely to be encountered at the eventually chosen site. Visit the link above to see the whole document, for a more complete presentation of all the sites we've considered so far, visit our WAIS 2000 poster below. Poster presented at Sept., 2000 WAIS meeting.This is what the poster looked like:
... click here for a tour of the poster contents. - D. Morse, 10/00 Manuscript in pressYes all this work finally became a paper that was presented at the IGS Symposium on Ice cores and Climate, held in Kangerlussuaq, Greenland, August 19-23, 2001 and submitted to the accompanying volume of Annals of Glaciology. We all know how agonizingly slow the wait can be for Annals volumes to actually come out, so for the benefit of keeping the site-selection process moving along, I'm violating the IGS/Annals copyright agreement and making the materials available now. Click here for an Adobe "pdf" document that I've formatted to look something like how a reprint might. Can't wait to download the manuscript and read the conclusions? Well here's the bottom line: deep ice make mo better core. A primary motivation for deep coring in West Antarctica is to recover a climate record that has sufficient temporal resolution for examining the hemisphere lead-lag question, an a core extracted from the thick-ice sites such as B or E will give better time resolution and core integrity during the glacial.
More events in the news:We've been funded to continue this line of work under new collaborative grant with the University of Washington to carry our ground based radar and ice motion surveys in the divide region. Visit the follow-on project web page here. Also, Ken Taylor at the University of Nevada, Desert Research Institute has been funded to oversee design and construction of a drill to do the deed. Visit the WAISCORES website at DRI Here. 2003 ICWG MeetingIn preparation for discussions at the 2003 Ice Core Working Group meeting, a question came up: Can the EPICA drill do the job? The drill has operational requirement of less than -8 degrees C. So, is this a constraint on the age of recoverable core? Lets take a closer look at the models.
Figure above: Temperature, annual layer thickness and timescale for sites B, E and G Table below: revised model summary including age at -8 C.
... so, what's the upshot? Looks to me that even considering the limitations of the EPICA system, it is clearly sufficient for recovering an ice core with age span and resolution to achieve the science priorities established by the WAISCORES community.
- DLM 3/03 Final Manuscript published, check it out: Morse, D.L., D.D. Blankenship, E.D. Waddington, T.A. Neumann. 2002. A site for deep ice coring in West Antarctica: Results from aerogeophysical surveys and thermo-kinematic modeling. Annals of Glaciology, 35: 36-44. Visit the follow-on project web page for more current information.
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