Low to Mid frequency propagation through Internal Waves during SW06 experiment M. Badiey B. Katsnelson J. Lynch

Objectives 3D effects of environment on the broadband propagation Establish different regimes of propagation, adiabatic, horizontal refraction, mode coupling Azimuthal dependency of the field due to IW propagation Geoacoustic inversion

Experimental Layout Sea floor Water depth ~80m ~1000 lb anchor WHOI VLA Thermistor string G 56 G 34 J15-3 SMH 0.3m 0.4m Variable range (5 to 40 km) Ship winch

Source: J15-3 –Freq. range: Hz –Long range Source: Three G34s –Frequency range: 1-3 KHz –Short range Sound sources

Low freq. band (<600Hz) from J15-3 –LFM or chirps –Sinc pulse –CW at multiple freq. points –M-sequence Middle freq. band (1-3 KHz) with three sources G34s –LFM –BPSK Signals Tested

MSM, NRL 300Hz NRL 500Hz WHOI 224Hz WHOI 400Hz WHOI VLA/HLA SHARK – A1 B1A B1 B1B C5A B5A A5A A3 B3 C1D C1A C1C J15: 79.3m J15: 75m J15: 50m C J15: 40.3m UD-L: 40m R/V HUGH R. SHARP ACOUSTIC RECEPTIONS C1B

Sample of received signal on the receiver array

Direction of dominant IW regimes observed during 21 days.

Tracks for Geoacoustic Inversion

Towed CTD data taken from the web for 8/9/06

 ww ss usus uwuw Surface Clutter NORTH VLA Source path IW “crests” Source

Depth (m) CTD#143CTD#144 Messured SSP Event#29 Geotime (Local)