Antartica - Victoria University

Project Proposal to Dhiresh Hansarajon
Meeting minutes: Friday 14th Dec

http://www.victoria.ac.nz/antarctic/

Dhiresh Hansaraj: MSc in Geophysics
Thesis title:Mapping Pliocene-Pleistocene seismic sequences in the Victoria Land Basin, Antarctica.
Project aim: To process and interpret new and existing seismic reflection data on the Ross Ice Shelf, adjacent to Ross Island, Antarctica.

Context of Research: Climate Change
Dhiresh was responding to:
John Mercer 1978- Prediction of 5-6m sea level rise
Milankovitch Cycles and Glaciation
Plus human influence

Base Data: marine seismic testing in McMurdo Sound
Seismic testing was to establish where sediment was well preserved
- not effected by ice advancing and receding in which sediment would be stripped
this stripping=stripping of "data" - like missing tree rings

Dhiresh classified his data as static - it could not be "strung together as moving snapshots"
It would also need to be stripped to be made user - friendly
Strong relationships could be made between seismic and the ice core data
The ice core reflected a 10cm record going back millions of years
The seismic data had ramification's for kms
the context was enlarged by other larger projects collecting seismic records in the basin (not just on the ice)

Marcia proposes visualizations of data through changing elevations
Dhiresh saw it through advancing receding coastline

Dhiresh is going to inform Peter Nash of the project and see what other data is available.
It is open to assist but is going overseas in the new year.

The larger aim of the Drilling on Ross Shelf is to understand how the Ross Shelf is behaving. So the pool of data - could involved: ice melt; temp; carbon - dioxide etc.


LINKS/REFERENCES FROM MEETING

http://www.homepage.montana.edu/~geol445/hyperglac/time1/milankov.htm
Milankovitch Cycles and Glaciation: The episodic nature of the Earth's glacial and interglacial periods within the present Ice Age (the last couple of million years) have been caused primarily by cyclical changes in the Earth's circumnavigation of the Sun.

Data Gathering: Stress-Triggering
Currently in California, Japan, Turkey
(would happen Wellington or NZ have this level)
Current Data Requests from GeoNet : http://www.geonet.org.nz/resources/basic-data/seismic-data/index.html

GNS Science Earthquake information
http://www.gns.cri.nz/what/earthact/earthquakes/index.html

Milankovitch Cycles and Glaciation:
http://www.homepage.montana.edu/~geol445/hyperglac/time1/milankov.htm

The episodic nature of the Earth's glacial and interglacial periods within the present Ice Age (the last couple of million years) have been caused primarily by cyclical changes in the Earth's circumnavigation of the Sun. Variations in the Earth's eccentricity, axial tilt, and precessionthe advance and retreat of Earth's glaciers. comprise the three dominant cycles, collectively known as the Milankovitch Cycles for Milutin Milankovitch, the Serbian astronomer who is generally credited with calculating their magnitude. Taken in unison, variations in these three cycles creates alterations in the seasonality of solar radiation reaching the Earth's surface. These times of increased or decreased solar radiation directly influence the Earth's climate system, thus impacting

It is of primary importance to explain that climate change, and subsequent periods of glaciation, resulting from the following three variables is not due to the total amount of solar energy reaching Earth. The three Milankovitch Cycles impact the seasonality and location of solar energy around the Earth, thus impacting contrasts between the seasons.

http://www.geonet.org.nz/resources/basic-data/seismic-data/index.html

Seismic Data
The GeoNet seismic data holdings may be queried, and data retrieved, using AutoDRM (Automatic Data Request Manager).

Broadband Guralp CMG-3ESP seismometer.

Introduction

AutoDRM is an email-based request tool for seismic data collected by the GeoNet project from broadband instruments of the New Zealand National Seismograph Network, the regional networks' (mainly) short-period seismometers, and the national strong motion network accelerographs. Request emails are to be addressed to autodrm @ geonet.org.nz. The station codes may be viewed on the network maps, and the site locations and operational dates may be found in DELTA.

Data Formats

The GeoNet AutoDRM supports three data formats for the extraction of waveforms; GSE2.0, SEED, and miniSEED. Data may be requested in these formats by supplying one of the following arguments to the WAVEFORM parameter of the request email: GSE2.0, SEED, MSEED.

Mercer, J.H. 1978.
"West Antarctic ice sheet and CO 2 greenhouse effect: a threat of disaster."
Nature 271:321-325.
http://www.nature.com/nature/journal/v271/n5643/abs/271321a0.html
http://citeseer.ist.psu.edu/contextsummary/1100856/0
West Antarctic ice sheet and CO2 greenhouse effect: a threat of disaster

J. H. Mercer

If the global consumption of fossil fuels continues to grow at its present rate, atmospheric CO2 content will double in about 50 years. Climatic models suggest that the resultant greenhouse-warming effect will be greatly magnified in high latitudes. The computed temperature rise at lat 80° S could start rapid deglaciation of West Antarctica, leading to a 5 m rise in sea level.
This paper is cited in the following contexts:

---

Assessing Climate Change: Co-evolution of Knowledge.. - Long, Iles (1997) (Correct)

....would likely cause catastrophic WAIS disintegration. He projected that, based on then current fossil fuel consumption, a rapid five meter rise in sea level caused by deglaciation of West Antartica may be imminent or in progress after atmospheric carbon dioxide concentrations have only doubled (Mercer, 1978). Mercer s (1978) article directed a great deal of attention to the possibility of WAIS disintegration and subsequent sea level rise (Oerlemans, 1989) As a result, sea level rise assessments during the late 1970s (e.g. the DOE AAAS workshop (DOE 1980) and Schneider and Chen (1980) referred to ....

....cause catastrophic WAIS disintegration. He projected that, based on then current fossil fuel consumption, a rapid five meter rise in sea level caused by deglaciation of West Antartica may be imminent or in progress after atmospheric carbon dioxide concentrations have only doubled (Mercer, 1978) Mercer s (1978) article directed a great deal of attention to the possibility of WAIS disintegration and subsequent sea level rise (Oerlemans, 1989) As a result, sea level rise assessments during the late 1970s (e.g. the DOE AAAS workshop (DOE 1980) and Schneider and Chen (1980) referred to and utilized ....