Transcript Ellesmere Island coast in Kennedy Channel, Aug.-12, 2009 1 of 27

Ellesmere Island coast in Kennedy Channel, Aug.-12, 2009
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Velocity:
Long-Range
Sonars
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Sonars send and receives acoustic waves
Measured Doppler shift proportional to
velocity
75 kHz transducers
Rigid Backbone allowed to
Pitch and Roll, but NOT
Change Heading
Magnetic Compass unusuable:
Kennedy Channel ~2800 nT
Fram Strait
~ 5800 nT
magnetic field strength
Low-Pass Filtered Current Vectors at Center of Channel
High-resolution Power-spectra of Depth-averaged Flow at KS10
Semi-diurnal band
Diurnal band
All frequencies
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Mean Along-Channel Velocity
(cm/s)
Along-Channel Freshwater Flux
(mSv per km per meter rel. to 34.8)
Along-Channel velocity fluctuations
(cm/s)
Three-year along-channel currents from ADCP mooring (KS02)
Depth (m)
2003/04
2004/05
2005/06
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10 Days
Spectral Density
(cm/s)^2 per cpd
Winter
(Landfast Ice)
Summer
(Mobile Ice)
Selection of Time Scale:
Cumulative Variance
by time scale (1/frequency)
Cumulative Variance
by frequency
Spectral Density
Volume Flux
Spectral Density
Along-Channel Sealevel Difference
Chosen Cut-Off
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Filter Design
Cut-Off: ~20 Days
Good Filter:
Lanczos Raised Cosine
Bad Filter:
Running Average
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Residual root mean square:
0.19 Sv
Correlation: r2=0.71
Regression: a= -0.84 Sv
Regression b=8.54 Sv/m
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2-D Power-Spectrum
[Time Scale]
(dispersion curves?)
From: Max-Planch Institute
Solar Systems Research
[Space Scale]
http://www.mps.mpg.de/projects/seismo/NA4/SW/power_spectrum.html