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

Magnetic Compass unusuable:

Kennedy Channel ~2800 nTFram Strait ~ 5800 nT

magnetic field strength

Velocity:Long-Range

Sonars• Sonars send and receives acoustic waves• Measured Doppler shift proportional to

velocity• 75 kHz transducers

Rigid Backbone allowed toPitch and Roll, but NOTChange Heading

Low-Pass Filtered Current Vectors at Center of Channel

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High-resolution Power-spectra of Depth-averaged Flow at KS10

All frequencies

Diurnal band

Semi-diurnal band

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)

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2004/05

2003/04

2005/06

Three-year along-channel currents from ADCP mooring (KS02)D

epth

(m)

Winter(Landfast Ice)

Summer(Mobile Ice)

Spectral Density(cm/s)^2 per cpd

10 Days

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Spectral DensityVolume Flux

Spectral DensityAlong-Channel Sealevel Difference

Cumulative Varianceby frequency

Cumulative Varianceby time scale (1/frequency)

Chosen Cut-Off

Selection of Time Scale:

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Good Filter:

Bad Filter:

Filter Design

Lanczos Raised Cosine

Running Average

Cut-Off: ~20 Days

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Residual root mean square:0.19 Sv

Correlation: r2=0.71Regression: a= -0.84 SvRegression b=8.54 Sv/m

2-D Power-Spectrum(dispersion curves?)

http://www.mps.mpg.de/projects/seismo/NA4/SW/power_spectrum.html

From: Max-Planch InstituteSolar Systems Research

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