Statistical Engineering Division Seminar
Global Change Recorded in Mid-Latitude Ice Cores
from southern North America and Central Asia:
Implications for Environmental Stewardship and Decision Making
Dr. L. DeWayne Cecil
Chief Scientist
NASA Applied Sciences Program
Statistical Engineering Division Seminar
Thursday May 18, 2006, 2:00-3:00 PM
Administration Building, Lecture Room C
Abstract
A collaborative global research program in mid-latitude glacial
and cave environments is underway to
- study the effects of increased loading of anthropogenic
heavy metals and radionuclides on alpine ecosystems,
- determine the paleoclimate signals in the ice and the
timing of regional climate change, and
- establish the key limiting factors on future climate-change
projections on a watershed scale.
This research program includes the collection of isotopic and
geochemical data archived in ice deposits from the Upper Fremont
Glacier located in the Wind River Mountain Range, Wyoming, U.S.A.,
the Inilchek Glacier located in the Tien Shan Mountains in the
Republic of Kyrghyzstan in central Asia, and in a recently
discovered cave in the Salmon-Challis National Forest, Idaho.
Mid-latitude glacial sites also are being studied in China,
New Zealand, Nepal, and Russia. Geochemical records preserved in ice
and snow collected from these mid-latitude sites include seasonal
fluctuations of naturally produced stable isotopes such as
oxygen-18 and oxygen-16, anthropogenic radioactive fallout such
as plutonium, tritium, chlorine-36 (36Cl), and iodine-129 (129I),
and signals from global and regional events such as volcanic
eruptions, droughts, and forest fires. Organic matter preserved
in the ice also provides a means to age-date sections of ice cores
by using the carbon-14 inventory. Projected warming rates for
the 21st century in the western United States range from
approximately 0.2ºC to 0.6ºC per decade. Such changes, unless
offset by changes in precipitation, may cause large-scale retreat of
the extant glaciers and cave-ice deposits in the Rocky Mountain West.
To determine the likely response, a 2-D numerical model of
energy/snow balance and ice flow was used to simulate the impact of
projected climate changes on a glacier for which some relatively
long-term monitoring data are available: the Upper Fremont Glacier
(UFG) in Wyoming's Wind River Range. We demonstrate how the model
can be used to infer climatic characteristics of past glacial
advances and compare results to other paleoclimatic proxies
collected at and near the UFG. These proxies include isotopic and
geochemical profiles generated from ice cores and an archive of plant
growth from a tree core collected near this site. The isotopic and
geochemical data gained from analyses of these glacial and cave-ice
records have lead to a reevaluation of the timing of climate and
environmental changes. An example of the environmental implications
of the archived record in these snow and ice deposits and their
effect on decision support will be discussed. Additionally, the
requirement for characterization, quantification, and
communication of uncertainties associated with
this research will be introduced.
NIST Contact:
Will Guthrie,
(301) 975-2854.
Date created: 5/9/2006
Last updated: 5/9/2006
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