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exploration. A continent-wide mosaic of Advanced Very
High Resolution Radiometer (AVHRR) satellite imagery
prepared by the USGS in 1991 and revised in 1996
afforded a similar leap forward [ Ferrigno et al. , 1996].
Although significantly poorer in resolution than Landsat
(about 1 km per pixel), the AVHRR satellite map
removed the latitude restriction and documented the East
Antarctic ice sheet in its entirety. This in turn led to the
discovery of  several key icefields distant from the
Transantarctic Mountains, notably the informally named
LaPaz icefields. In the same time frame, Radarsat imagery
also proved useful to ANSMET. It too was relatively
limited in resolution (around 125 m per pixel) but had no
latitude restrictions and when properly processed distin-
guished dense, bubble-free blue ice from surface snow.
Comparisons of Radarsat and AVHRR datasets proved
valuable in the identification of many of the icefields
studied by ANSMET, particularly those in the most
southerly Transantarctic Mountains.
Today ANSMET relies on two current-generation
products for its remote sensing needs, both provided
through the USAP-supported Polar Geospatial Center
(PGC) at the University of Minnesota. First is imagery
from the MODIS (Moderate Resolution Imaging
Spectroradiometer) Rapid Response System [ Justice et al .,
1998]. MODIS instruments aboard both the Terra and
Aqua satellites image the entire Earth's surface every one
to two days at ~250 m/pixel, acquiring data in 36 different
spectral bands. The Rapid Response System provides
daily images of Antarctica in true color. These images
have proven exceptionally useful for direct confirmation
of the presence of blue ice, and their daily recurrence
allows selection for cloud-free views with limited snow
cover and maximum Sun angles, helping us identify many
smaller icefields throughout the Transantarctics and
reducing our dependence on reconnaissance overflights.
When localized detail is needed, such as to serve as a
base map for meteorite searches, the PGC also provides
ANSMET with high-resolution satellite imagery. This
imagery, licensed by the PGC from GeoEye, Digital
Globe, Ikonos, and other sources, can have resolutions as
high as 1 m/pixel. The main value of such images is in the
tremendous geographical control they provide when used
in concert with GPS-derived meteorite and base station
locations.
Planning for individual seasons typically begins about
eight months before any given austral summer, with the
preparation and submission of a detailed support request
to USAP. Called the Support Information Package (SIP),
this document summarizes and formalizes ANSMET's
needs across a broad spectrum of categories, including
the specific targets for field work; a schedule of support
events; participant lists; permitting needs (to comply with
Antarctic treaties and federal regulations); shipping and
cargo handling; potential environmental impacts; staging
and storage needs; field equipment requests; laboratory,
computing, and communication needs; food and fuel
requirements; and myriad other details. This document,
often 70+ pages for each field party, becomes the basis for
negotiations between the project and USAP contractors,
eventually leading to concurrence before the start of
fieldwork in November.
Field party selection typically takes place in the same
time frame as the support request SIP preparation.
ANSMET field teams typically consist of a science leader
(ANSMET project personnel), a mountain guide who
also serves as camp manager, and a mixture of ANSMET
veterans and first-time volunteers, with a targeted ratio
of experienced to first-time field party members around
50:50. ANSMET is relatively unique among Antarctic
field projects in that we welcome the involvement of vol-
unteers from the research community, including interna-
tional participants. Preference is given to those whose
research involves Antarctic meteorites, but individuals
with related research and/or significant related experience
are also considered. After selection by the ANSMET
principal investigator, all applicants must pass a set of
qualifying medical and dental screening exams required
by USAP due to the limited emergency treatment avail-
able in Antarctica. Inclusion of volunteers from the
planetary research community does pose challenges,
given that some have limited field experience in isolated
or cold weather environments. However, the payback has
been significant, since inclusion of volunteers reinforces
the altruistic nature of the Antarctic meteorite program
as a whole, encourages continuous and conservative field
safety training, promotes highly efficient and robust field
practices, lowers costs, and perhaps most importantly,
injects new energy into the fieldwork each season. As of
this writing, more than 170 scientists have participated in
ANSMET fieldwork, and our record of safe field opera-
tions and continuous recoveries validates the inclusion of
newcomers to the program.
2.2.3. Field Season Structure and Logistics
The basic unit of ANSMET activity is the field season:
the annual period when one or more teams are deployed
to target icefields for as long as six weeks. Fieldwork typ-
ically begins in early December, when the Sun is at its
highest and the lack of diurnal atmospheric cooling helps
to minimize katabatic winds on the East Antarctic
Plateau. The season often continues until late January,
when logistical support in the McMurdo region shifts
away from science and toward preparations for the com-
ing Antarctic winter.
McMurdo Station, the largest U.S. base in Antarctica,
serves as USAP's hub for operations in the Transantarctic
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