COLD HAWAII
1
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Airborne LIDAR measurements
around the APLIS camp
Henriette Skourup hsk@space.dtu.dk
Rene Forsberg, Susanne Hanson and Sine M. Hvidegaard
1
Height measurements of Sea Ice
Resolution: 1x1 m
40 Hz scan rate
Infrared 900 nm
300 m swath at 300 m altitude
SEA SURFACE
ICE
3
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Conversion of freeboard to thickness
Conversion of measured sea ice
freeboard heights (F) into
ice thicknesses (T) depends on:
- Snowdepth
- Density of the ice, water and snow
The snowdepth and density changes locally
and can be determined from:
- Climatic Models
- In Situ measurements (e.g. by drilling)
- Coincident draft and surface measurements
(AUV/ULS/EM versus laser)
T = K *F
K = 1+
ρi hi + ρ s hs
hi ( ρ w − ρ i ) + hs ( ρ w − ρ s )
K 2006 = 6.1
F
S
Snow
T
Ice
Water
4
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
2
Flight Tracks 2007
April 9-10
April 10-12
April 12
April 13
April 14
April 15
April 16
April 17-20
April 21
April 22
April 23 -27
April 27
April 28-30
May 1
May 2
May 3
May 4
May 5
May 6
May 7
5
DTU Space, Technical University of Denmark
Re-Installation of equipment, Calgary
Flight to APLIS07
Local survey at APLIS07
APLIS07 to Resolute
No flying due to bad weathe
Resolute to St. Nord: fuel pump to
DC-3, no survey
Medivac Borneo
No flying due to snow storm at St. Nord
St. Nord to Alert
Alert to Tara via Borneo
Local flights out of Tara, Buoy drops etc.
Breakup of runway. Tara to St. Nord
Shuttle service Tara to new DC-3 runway
Local survey out of St. Nord
St. Nord to Longyearbyen
Installation of radar equipment
Local flight Austfonna and Kronebreen
Uninstallation of radar
Longyearbyen to Alert
Local survey out of Alert, submarine survey
No flying due to bad weather at Alert
Local flight nord of Alert, Alert to Resolute
Unistallation of equipment
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Installation Calgary March 2007
6
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
3
Local survey at APLIS, JD 102 April 12, 2008
Submarine Track
ICESat Track
EM-bird
Mow-the-lawn
ICESat
EM-bird
7
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Calibration of scanner data
8
DTU Space, Technical University of Denmark
4
Mow-the-lawn
Mean:
0.61 m
St. Dev.:
0.25 m
9
DTU Space, Technical University of Denmark
Corrected for drift by GPS
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Overflight of ice camp
Runway
10
DTU Space, Technical University of Denmark
5
AUV area 1x1 resolution
Statistics:
Probability Density Function (PDF)
Ridge Statistics
11
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Inner Buoy Array ~10 km
Freeboards:
Mean:
0.61 m
If compared to EM conversion-
Std. dev.:
0.26 m
factor K ~ 4.3
0,25
0,2
0,15
0,1
0,05
4,
8
4,
5
4,
2
3,
9
3,
6
3
3,
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
0,
3
0
Inner buoy array
Mean
[m]
Median St. Dev. Open Water
[m]
[m]
Fraction [%]
Length
[km]
EM
April 5
2.61
2.46
1.25
111.4
EM
April 9
2.59
2.40
1.23
112.0
12
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
6
Crossings at Inner Buoy Array
13
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Upward looking Sonar (ULS)
HMS Tireless – inner buoy array
TIMES March 16-20 ?!?
14
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
7
Inner buoy array ~ 10 km
0,25
74356-74359
0,2
0,15
0,1
0,05
4,
8
4,
5
4,
2
3,
9
3
3,
6
3,
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
0,
3
0
0,25
74358-74364
0,2
0,15
0,1
0,05
4,
8
4,
5
4,
2
3,
9
3,
6
3
3,
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
0,
3
0
0,25
74363-74354
0,2
0,15
Mean [m]
Std. dev. [m]
Min. [m]
Max. [m]
74356-74359
0.58
0.24
-0.12
3.06
74358-74364
0.53
0.25
-0.06
3.87
74363-74354
0.67
0.26
-0.15
3.98
0,1
0,05
DTU Space, Technical University of Denmark
4,
8
4,
5
3,
9
4,
2
3,
6
3
3,
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
15
0,
3
0
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
APLIS – 74311 ?!?
16
DTU Space, Technical University of Denmark
8
Outer buoy array ~ 70 km
0,25
APLIS - 74361
0,2
0,15
ICE 1
0,1
0,05
0,25
4,
8
4,
5
4,
2
3,
9
3,
6
3
3,
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
74361
0,
3
0
74361 – ICE 1
0,2
0,15
0,1
0,05
0,25
4,
8
4,
5
4,
2
3,
9
3,
6
3,
3
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
0,
3
0
APLIS
ICE 1 – ICE 2
0,2
0,15
ICE 2
0,1
0,05
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
4,
8
4,
5
4,
2
3,
9
3,
6
3,
3
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
17
0,
3
0
October 27-31, 2008
EM-bird
Mean [m]
0.55
Std. dev. [m]
0.26
Min. [m]
-0.11
Max. [m]
4.98
74361 – ICE1
0.54
0.25
-0.09
4.22
ICE 1 – ICE 2
0.59
0.26
-0.11
5.68
APLIS – 74361
Outer buoy array
Mean Median [m] St. Dev.
[m]
[m]
Open Water Length [km]
Fraction [%]
EM
April 4-5
2.70
2.51
1.26
0.02
533.7
EM
April 11-12
2.59
2.43
1.42
0.40
613.3
If compared to EM on April 11-12: K ~ 4.7
18
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
9
ICESat track ~70 km
19
DTU Space, Technical University of Denmark
Nearest ICESat Track:
JD 76
Laser scanner flight:
JD 102
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Regional study Inuvik-APLIS, April 12
0,35
0,3
0,25
Mean:
0.43 m
Std. dev.:
0.27 m
0,2
0,15
0,1
0,05
DTU Space, Technical University of Denmark
4,
8
4,
5
4,
2
3,
9
3,
6
3
3,
3
2,
7
2,
4
2,
1
1,
8
1,
5
1,
2
0,
9
0,
6
0
20
0,
3
0
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
10
Regional study APLIS-Sach Harbour, April 13
0,25
0,2
0,15
Mean:
0.49 m
Std. dev.:
0.27 m
0,1
0,05
DTU Space, Technical University of Denmark
4,
8
4,
5
4,
2
3,
9
3
3,
6
3,
3
2,
7
2,
4
2,
1
1,
8
1,
2
1,
5
0,
9
0,
6
0
21
0,
3
0
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
Comparisons ?!?
•
•
•
•
•
•
•
22
ULS comparison, inner array – ... Peter Wadhams
EM comparison ...
Ben Holt L-band ridge detection
AUV comparison .. Martin Doble/Peter Wadhams
ICESat ?!?!
Insitu measurements for k-factor ... Freeboard/thickness conversion
Ridge statistics ?!?
DTU Space, Technical University of Denmark
SEDNA Workshop, Henriette Skourup
October 27-31, 2008
11