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Woods Hole Coastal and Marine Science Center

The Massachusetts Bay Internal Wave Experiment, August 1998: Data Report

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Scatter Plots

Scatter plots of the one minute and low-passed currents (calculated from hourly averaged data and subsampled by 6) visually show the distribution of the current speed and direction. Superimposed on the scatter plots are the mean vector current over the entire deployment (red arrow), and the principal axes of the currents (red ellipse centered at end of mean vector).

Site B Horizontal Array (FSI)
Site B Subsurface (FSI, VMCM)
Site B Tripod (ADCP, BASS)
Site C Subsurface (VMCM)
Site C Tripod (ADCP)
Site D/MBLT-B Tripod (ADCP)

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Principal axes of the currents were computed for the entire data record (using data at the basic sampling interval). Major (Maj) and minor (Min) axes, orientation (OR), and ellipticity (EL) were computed from the east (u) and north (v) current components as:

major axis = [0.5 (UU + VV) + R] / n}(1/2)
minor axis = [0 5 (UU + VV) - R] / n}(1/2)
orientation = 90° - 0.5 tan-1 [2 UV / (UU - VV)]
ellipticity = 1 - (minor axis / major axis)

where

UV = Sum(u*v) - n*U*V

UU = Sum(u*u) - n*U*U
VV= Sum(v*v) - n*V*V
R = [ (0.5 (UU - VV) )2 + (UV)2 ](1/2)

and U and V are the means of the east and north velocity components (in cm/s), respectively. The orientation (OR) is measured clockwise from true north. 0° is true north, and 90° is east. The depth is measured in meters below the surface, and the sampling interval (SI) is in minutes. EL is ellipticity.

Site Inst. Depth Start Time End Time SI Maj Min OR EL
B FSI 1467 20 8/6/1998
20:26
8/30/1998
2:29
1.5 11.99 5.72 252 0.52
B FSI 1468 20 8/6/1998
20:36
8/30/1998
2:27
1.5 12.24 5.67 252 0.54
B FSI 1469 20 8/6/1998
20:26
8/30/1998
2:27
1.5 12.13 5.77 252 0.52
B VMCM 0014 50 7/30/1998
21:18
9/9/1998
19:07
1 8.23 3.35 266 0.59
B VMCM 0009 75 7/30/1998
20:02
9/9/1998
18:57
1 8.64 2.53 267 0.71
B FSI 1428 80 8/6/1998
15:59
9/1/1998
9:59
1.5 11.14 3.17 262 0.72
B ADCP 5372 76 8/4/1998
13:31
9/2/1998
0:00
1 10.47 3.02 264 0.71
B BASS 5371 84 8/4/1998
13:30
9/2/1998
12:38
1 8.11 2.88 264 0.64
B BASS 5371 84.6 8/4/1998
13:30
9/2/1998
12:38
1 6.69 2.36 261 0.65
C VMCM 5344 45 8/5/1998
11:30
9/1/1998
18:30
1 11.71 4.84 253 0.59
C ADCP 5352 45 8/4/1998
10:31
9/1/1998
19:11
1 11.80 4.96 246 0.58
D ADCP 5322 5 6/17/1998
22:12
9/30/1998
16:12
15 11.55 8.10 23 0.30
D ADCP 5322 16 6/17/1998
22:12
9/30/1998
16:12
15 8.51 5.02 290 0.41

Table in Excel Format

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This page last modified on Monday, 14-Jan-2013 12:50:00 EST