Airborne Magnetic Measurements Associated with SW06 Experiment Will Avera Pat Gallacher, Wayne...
-
Upload
shannon-andrews -
Category
Documents
-
view
216 -
download
0
Transcript of Airborne Magnetic Measurements Associated with SW06 Experiment Will Avera Pat Gallacher, Wayne...
Airborne Magnetic Measurements Associated with SW06 Experiment
Will AveraPat Gallacher, Wayne KinneyNaval Research Laboratory
And
Brad NelsonDefence Research and Development Canada
SW06 Post-Experiment Meeting
Objective / Purpose
• Measure magnetic fields in the vicinity of NLIW’s
• Test theoretical predictions – Internal waves can produce measurable magnetic
signatures
Plan / Measurements
• 12 flight lines were collected over NLIWs on August 2, 2006– 4 lines @ 300’ (Lines 1,2,3,4)– 4 lines @ 500’ (Lines 5,6,11,12)– 2 lines @ 1000’ (Lines 7,8)– 2 lines @ 2000’ (Lines 9,10)– each line was ~ 10 minutes in length (~ 60 km) + 3 minutes per
corner– All lines were along the same track
• 39.5317 N , 73.6478 W to 38.9560 N , 73.0213 W
• Start point and bearing for this line were given to us by Jim Moum who was on the OCEANUS
• OCEANUS was in the middle of one NLIW packet
SW06
NRC Convair flight line
Simulations and Analysis -Very high resolution -MITgcm nonhydrostatic simulation -Forced with nested NCOM -Focus on nonlinear internal wave -Based on previous work including -MITgcm simulations of Hudson Canyon generation area -Nested NCOM simulations of high amplitude internal waves on shelf and slope in SW06
SW_06_new Domain (0.5km)current simulations
LBSF Domain (0.5km)future simulations
SW06 Moorings
The NRC Convair
• Convair data acquisition system – 3 Cesium total-field magnetometers– 2 vector magnetometers for compensation– Attitude and noise sensors– Post-processed DGPS navigation @ 4 Hz
500’ Results: Track Reproducibility : Lines 5,6,11,12
• Excellent reproducibility => Good geologic noise removal
All 4 Lines OverlyLine 11
Unfiltered
So
uth
No
rth
Magnetic Results: 500’ Alt - Lines 5, 6, 11, 12
• OCEANUS located near the internal wave activity • OCEANUS location sufficiently distant not to be disturbing measurements
NLIW ?
OCEANUS
Lt. Blue = Line 11
Ships > 1 mile off line
Black = Line 5
Blue = Line 6
Green =Line 12
Magnetic DataModel : U Velocity
1700 UT
1600 UT
1500 UT
Magnetic Results: 500’ Alt - Lines 5, 6, 11, 12
• OCEANUS located near the internal wave activity • OCEANUS location sufficiently distant not to be disturbing measurements
NLIW ?
OCEANUS
Lt. Blue = Line 11
Ships > 1 mile off line
Black = Line 5
Blue = Line 6
Green =Line 12
Magnetic DataModel : W Velocity
1700 UT
1600 UT
1500 UT
Conclusions (So Far)
• Data processing techniques – Appear to work for external magnetic noise reduction
• Anomalous residual noise on east side of the line is good candidate for NLIW – Jim Moum claimed the ship was in the middle of the NLIW– Residual noise correlated with OCEANUS position