Sea Ice Thickness Measurement in the Chukchi Sea using a Shipborne ElectroMagnetic Inductive Devise

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Sea Ice Thickness Measurement in the Chukchi Sea
using a Ship-borne Electro-Magnetic Inductive
Devise (SEM)
K. Tateyama (Kitami Inst. Of Tech., Japan)
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SEM Result
Sea ice thickness changes in Arctic
-Method - Ice thickness distribution - Problems
Satellite remote sensing
-Comparison between ice thickness data taken by
SEM and past submarine
-Validation of sea ice type detecting algorithm -
effect of surface melting
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Sea-ice thickness measurements
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Problem in the video method

• Needs breaking ice

Video Method
Ice- breaker
Thickness
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Principle of shipborne EMI
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Outline of SEM set up on the ice-breaker
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SBI-04 observation 2004/5/15-6/20
Alaska
Ship track
Coastline
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Result Calibration
Method Changing height of SEM (0.15m int.) Over
the MY and FY ice ? Taking ice cores to
measure ice temp. and salinity. Measuring ice
thickness and water temp and salinity. ?
sa-ZE conversion formula
Ice-free model Uto et. Al., 2001
Error within 5
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Comparison of calibrations between the Chukchi
Sea, the Eastern Antarctic Sea and the Sea of
Okhotsk
Fresh, cold
Saline, cold
Saline, warm
Derived from ice core analysis and CTD
measurements
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Result Ice thickness distribution 1hr ave
Have1.68m
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Problem Effect of ramming
Pack ice area
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Comparison with sea ice thickness record
1989
1988
1987
1986
Submarine 1986-1994 (NSIDC)
2004, SBI-04 1.5-2.5m
1993
1994
1992
1991
Thinning?
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Validation of satellite remote sensing
AMSR-E NASA Team algorithm
6/15
5/15
6/21
6/28
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Ice type change B FYgtMY, O MYgtFY
AMSR-E NASA Team algorithm
5/15
6/15
6/21
6/28
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Ice type change B FYgtMY, O MYgtFY, R Melt
AMSR-E TB index (in this study)
5/15
6/15
6/28
6/21
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Air temp from ship sensors, Microwave
radiometer (AMSR-E), SEM
M Y
M Y
M Y
F Y
F Y
F Y
MELT
F Y
F Y
M Y
F Y
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RESULT Relationship between Air temp and TB
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Brightness Temperature TB Emissivitye
Physical temperature T
TB index TB(6-37GHz)/TB(89GHz)
TB index gt 1.05 ? MY 0.95?TB index
?1.05 ? FY TB index lt 0.95 ? Melt
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RESULT TB index
First-year ice Multi-year ice Melting on FY
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RESULT Relationship between SEM thickness and TB
index
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Summary

• In the Chukchi Sea, the Ice-free model can be
  used.
• The accuracy of this model showed within 5.
• Sea ice conductivity is low as compared with the
  
• Antarctic Sea and the Sea of Okhotsk.
• The ratio of thinner ice has been increased in
  the
• Arctic region.
• These data will be used for developing global
  sea
• ice thickness estimation method by satellite
• passive microwave radiometer.