Post on 23-Jan-2016
description
Ice studies off West Greenland 2006
Bureau of Minerals and Petroleum
Government of Greenland
Data compiled bySine M Hvidegaard, Rene Forsberg, Susanne Hanson
Danish National Space CenterLeif Toudal
Ørsted • DTU
West Greenland ice studies 2006
Basic objectives– Measure ice thickness
and ridging– Calibrate airborne
measurements by in-situ drilling
– Compile historic data on ice distribution and drift
– Measurement of ice drift with buyo
QAARSUT
KANGERLUSSUAQ
T12
West-Ice flight tracks 21/25 April 2006
Southern line – approx 3 km section. Numerous thick floes and ridges
The swath shows colour-coded sea ice thickness data including the snow depth on top of the ice
Laser ice thickness measurement
68.014
68.012
-57.900
-57.880
-57.860
-57.840
0.0 1.0 2.0 3.0m
.
Laser ice thickness measurement
Northern line – approx 2 km section. V10 is helicopter drill site position
71.025
71.020-56.32 -56.30 -
56.28-56.25
0.0 1.0 2.0 3.0m
Average laser ice thickness
1.39 m
70.6 %1.40 m
80.0 %
1.19 m
67.6 %
1.23 m
66.0 % 1.10 m
65.8 %
2.13 m
77.2 %1.78 m
83.3 %
1.28m
72.9 %
1.63 m
73.5 %1.29 m
66.1 %
1.33 m
63.8 %
1.32 m
83.6 %
V1 – V2
V3 – V4
V5 – V6
• Plot shows mean ice thickness for the E-W laser survey lines, for each 2° in longitude
• Numbers shown are the average thickness in meter and the % of ice thickness above 80 cm.
• The thickness includes snow depth and pressure ridge heights; floe ice thickness is therefore significantly less.
• Average of helicopter measurements on flat floes: 65 cm, with 40% > 80 cm
V3-V4
00,020,040,060,08
0,10,120,14
0 2 4 6 8 10
Ice thickness, m
Pd
f
V1 - V2
0
0,02
0,04
0,06
0,08
0,1
0,12
0 2 4 6 8 10
Ice thickness, m
Pd
f
Ice-thickness distribution
Helicopter overflight, V5 - V6
0
0,05
0,1
0,15
0,2
0 2 4 6 8 10
Ice thickness, m
Between Helicopter overflight and coast line,
0
0,05
0,1
0,15
0,2
0,25
0,3
0 2 4 6 8 10
Ice thickness, m
Pd
f
In-situ ice-thickness measurements
• 40x40 m area selected corresponding approx. to in-situ measuring site
• Average of laser-scanner-derived ice thickness in area compared to average of drillings
• In-situ: 0.56 m• Scanner: 0.79 m ± 0 .30 m
(std. dev.)• Large variation in area is
the main cause of the difference
Point Ice thickness
range (cm)
Average thickness,
(cm)
Aver. snow
depth, (cm)
V10 45-60 53 3
V11 22-40 32 1
V13 42-140 (two floes)
91 5
V14 39-60 45 2
V15 98-105 102 3
Uummannaq fast ice(6 pts)
25-52 44 4
In-situ ice-thickness measurements
In-situ/laser measurement comparison
In-situ: 1.05 mScanner: 1.44 m
In-situ: 0.96 mScanner: 0.78 m
In-situ: 0.56 mScanner: 0.79 m
End of the ice season (end of June)
AMSR-E ICE 20050701 AMSR-E ICE 20060628
Distribution of sea ice 2004–2006
• Amimations of sea-ice distribution and cover 2004–05 (left) and 2005-06 (right)
• Sea ice cover:Purple:~100 %Red: > 90 %Orange: > 70–85 %Yellow: > ~50 %Green: ~30 %Blue-green: 10–20 %Blue: no ice or noise
Drift of polar multi-year ice
• Polar multi-year ice has a higher roughness than first-year ice – seen as bright green or yellow areas along the east coast of Canada
• Note that this ice does not drift into Greenland waters
25-year statistics
Minimum number of ice-free days Average number of ice-free days
Recent statistics
Minimum number of ice free days
25-year statistics
Minimum number of ice free days
2000–2005 statistics
Ice stations 2006/04/26
Drift track2006/04/26–2006/06/12
Sea ice studies 2006
Radar image June 12, 2006
20060426
20060612
50 km
2006 drift buyo experiment
• Comparison between buoy drift statistics 2006 and the 20 year satellite ice drift statistics
• Good correspondence, but satellite may under-estimate extreme values
Percentage of days in May where ice drift exceeds 10 km/dayYellow areas have few datapoints!
Ice drift in May
2006 buoy
20-year average
Pechora Sea
Beaufort Sea
Sakhalin
Caspian Sea
PrirazKara
Oil production in ice-infested waters
White Rose
Ice free
(# of days)Velocity
(>10 km/day) Area definition
mean
[min-max] [% of days with data]
Sakhalin
200 [180-245] 49 53-54N 143-145E
Baffin Bay [2000-2005]
60-250[100–250]
27
68-71N 54-61W
Pechora
193 [112-278] 11 69-70N 52-55E
Priraz
160 [98-223] 11 69-70N 56-58E
Kara
122 [50-192] 12 71-72N 62-65E
Beaufort
51 [0-140] 6 70.5-71.5N 145-150W
Comparison with other areas
Conclusions