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Using Flubber to Study Glaciers
A Hands-on Experience
Making a glacier from Flubber
Sources: Left: http://polenet.org/?page_id=137Right: http://www.geology.um.maine.edu/user/Leigh_Stearns/teaching/flubber.html
GPS
Diagram of what happens
This is land
Figures courtesy: John Wahr (U of Colorado)
Add load, perhaps a glacier
GPS
What’s going to happen to the GPS? Will it go up/down, closer/further from
the glacier?
Add load GPS
GPS moves downward and towards the load
The land flexes downward; the GPS moves downward and closer to the
glacier
GPS
Now the glacier melts. How will the GPS move?
remove load GPS
GPS receiver moves upward and away from the load
As the glacier melts, the GPS moves…
Measuring the Crust and Mantle Move
SourcesIce• Ice-age melting• Present-day
melting
Water • Ocean tides• Wind-driven surges• Reservoir depletion
Air• Water Vapor• Weather systems
as noise and signal (information)
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Measuring the Land Rebound (or Sink)
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Glacial Isostatic Adjustment
Vertical changes measured by GPS
Sel
la, G
. F.,
S. S
tein
, T. H
. Dix
on, M
. Cra
ymer
, T. S
. Jam
es, S
. Maz
zotti
, an
d R
. K. D
okka
(20
07),
Obs
erva
tion
of g
laci
al is
osta
tic a
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“sta
ble”
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orth
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eric
a w
ith G
PS
, Geo
phys
. Res
. Let
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4, L
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oi:
10.1
029/
2006
GL0
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1.
Green line shows 0 mmyr vertical “hinge line” separating uplift from subsidence.(left) Vertical GPS site motions (right) Horizontal motion Red vectors represent sites primarily affected by GIA. Purple vectors represent sites that include effects of tectonics.
Horizontal motions measure by GPS
GPS horizontal velocities with motion of rigid North America removed. Interpolated velocity field based on these data derived using GMT
Sel
la, G
. F.,
S. S
tein
, T. H
. Dix
on, M
. Cra
ymer
, T. S
. Jam
es, S
. Maz
zotti
, an
d R
. K. D
okka
(20
07),
Obs
erva
tion
of g
laci
al is
osta
tic a
djus
tmen
t in
“sta
ble”
N
orth
Am
eric
a w
ith G
PS
, Geo
phys
. Res
. Let
t., 3
4, L
0230
6, d
oi:
10.1
029/
2006
GL0
2708
1.
Horizontal GPS Motions
Fig. 5. Assessment of core station selection. Velocities of core stations (with yellow circles) are shown together with other frame stations, indicating the effects of plate boundary deformation in the west, and post-glacial rebound in the northeast. To compar... G
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a, J
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dyna
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s, V
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e 72
, 201
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1–24
. http
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/10.
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13.0
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Weighing the ice sheets
13
Continuous GPS in the Arctic
Short-term elastic deformation of the ice load, providing a measure of large-scale melting, and hence contribution to sea-level rise
Open circles are the POLENET network
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