168
M.R. DRINKWATER
Ice velocity acvf
Wind velocity acvf
Velocity ccvf
1.0
1.0
1.0
0.8
0.8
0.8
0.6
J
-0.2
-0.4
-0.4
-0.4
0
2
4
6
0
2
4
6
-6 -4 -2 0 2 4 6
time lag, day
time lag, day
time lag, day
Ice velocity
Wind velocity
Cross amplitude
auto spectrum
auto spectrum
spectrum
4
4
4
3
3
3
~
~
\ 2
' 2
\ 2
U
U
U·
10
100
1000
10
100
1000
10
100
1000
period, h
period, h
period, h
Coherency spectrum
Phase spectrum
1.0
100
,go
~
-100
10
100
1000
10
100
1000
period, h
period, h
Fig.9. a-h. Auto-covariance functions and normalized variance spectra of Argos-derived ice drift and
wind speeds for free drifting buoy in the central Weddell Sea during WWGS'92. For further details,
see text
level (900 mB) winds (Le., ageostrophic angle of the atmospheric boundary layer).
Thus ice drifts with an angle of approximately 25· to the left of the surface wind in this
July period. This turning angle is fairly typical of previous results observed by Martinson and Wamser (1990) for drifters in the eastern Weddell Sea in 1986.
M.R. DRINKWATER
Ice velocity acvf
Wind velocity acvf
Velocity ccvf
1.0
1.0
1.0
0.8
0.8
0.8
0.6
J
-0.2
-0.4
-0.4
-0.4
0
2
4
6
0
2
4
6
-6 -4 -2 0 2 4 6
time lag, day
time lag, day
time lag, day
Ice velocity
Wind velocity
Cross amplitude
auto spectrum
auto spectrum
spectrum
4
4
4
3
3
3
~
~
\ 2
' 2
\ 2
U
U
U·
10
100
1000
10
100
1000
10
100
1000
period, h
period, h
period, h
Coherency spectrum
Phase spectrum
1.0
100
,go
~
-100
10
100
1000
10
100
1000
period, h
period, h
Fig.9. a-h. Auto-covariance functions and normalized variance spectra of Argos-derived ice drift and
wind speeds for free drifting buoy in the central Weddell Sea during WWGS'92. For further details,
see text
level (900 mB) winds (Le., ageostrophic angle of the atmospheric boundary layer).
Thus ice drifts with an angle of approximately 25· to the left of the surface wind in this
July period. This turning angle is fairly typical of previous results observed by Martinson and Wamser (1990) for drifters in the eastern Weddell Sea in 1986.