pressed into glacial ice) over various
Met.
Bladder
OCAF
Tower
depths, and to locate or delineate sub-
Z
Grid North
surface facilities and utilities, or both.
S
(Greenwich
Meridian)
Taxiway
Figure 5 shows the general layout of
U
Fuel
W
South Pole Station and the surveys. The
Arch
Fuel Hut
R
WARR
facilities discussed are the present water
T
Biomed
V
X
well, several sewage sumps produced
Arch
over the years (indicated as sump 1,
Arch
sump 2 and far sump), a utilidor and the
Skylab
Garage
buried Old Clean Air Facility (OCAF).
Arch
Dome
Cargo
Each survey line is lettered (e.g., FG)
Arch
L
with the alphabetical order indicating
P
J
Far Sump
Balloon
the direction of the line. Several
0
H
B
Inflation
transects are indicated at each site, but
D
Elevated
N
E
not all are presented in this report as
Utilidor
Sewer Line
M
Vent
K
some did not traverse the features of in-
A Sump 1
I
C
terest. One Wide-Angle Reflection and
G
F
Water
Sump 2
receiver antenna offset constantly in-
Well
creased: on the diagram) was made near
the OCAF to evaluate the refractive in-
0
50
100
150
200 m
dex of the surface snow. Dielectric
information was gathered from all sur-
Q
veys. The weather during all profiles
was clear with light winds and tempera-
Figure 5. Layout of facilities and radar survey lines (end points
tures between 13 and 26C, which ne-
alphabetically marked) at South Pole Station, January 1993. Line
cessitated placing the radar control unit
marked WARR is a wide angle survey.
within an insulated box.
Near the surface, snow density is ap-
proximately 0.35 g/cm3 and increases to
a firn density of about 0.8 by 100 m
depth (Bogorodsky et al. 1985). About 1520 cm
Also apparent in all the records are diffractions
of new snow accumulates each year at the South
unrelated to the feature of interest. We expect that
Pole. The snow that was on the surface during the
these "clutter" events are generated by buried
beginning of the International Geophysical Year
objects including trash, spills, vents, cables and
(IGY; 1957) when the South Pole was first perma-
nently occupied was about 45 m below the sur-
face at the time of our surveys. Over the years ob-
Metal utilidor
jects have been buried. Some objects are even
The metal utilidor leading south from the main
deeper, since pits were dug to bury waste as far
station (Dome in Fig. 5) was first surveyed (line
back as the IGY. In the early 1970s, a second sta-
DE) to establish a calibration value for the snow
tion was built 1.4 km from the original IGY sta-
velocity since the exact depth (5.65 m) from the
tion, creating heavy vehicular traffic between the
snow surface to the crown of the metal tunnel
two stations. This created a hard, compacted lay-
was known. The utilidor tunnel itself is 2.0 m
er that, at the time of our surveys, was 3 to 4 m
high (Fig. 6). Figure 6 also shows the radar pro-
below the snow surface. That traffic area crosses
file, acquired with the 400-MHz transducer. The
routes proposed for a tunnel and is evident in
prominent but distorted hyperbolic diffraction
many of the radar surveys. Extra snow accumula-
under the centerline symbol and whose apex is at
tion around the main station places that layer 4 to
49-ns delay is the response to the utilidor roof.
5 m deep there and it is also visible in the radar
The reflected wavelet at the apex is the large re-
records. However, since all snow above it has
flection shown in Figure 1. Several other hyper-
since been compacted by annual snow control op-
bolas appear in the profile and are generated by
erations, other layers are also evident in the radar
buried objects whose depth and placement rela-
survey.
tive to the vertical plane of the survey line is not
6
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