The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder easternberings00hood Year: 1981 KILOMETERS EAST Figure 5-3. Progressive Vector Diagrams (A) Outer regime, BC-13A 20 m. (B) Middle regime, BC-6A 50 m. (C) Coastal regime, BC-15A, 20 m. These figures are the displacement of a water parcel having the same velocity as measured by the current meter, and may be quite different from the actual trajectory of any parcel. The outer record showed tides (cusps), strong pulses, and a northward mean. The middle record showed strong tides (clockwise elli
The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder easternberings00hood Year: 1981 KILOMETERS EAST Figure 5-3. Progressive Vector Diagrams (A) Outer regime, BC-13A 20 m. (B) Middle regime, BC-6A 50 m. (C) Coastal regime, BC-15A, 20 m. These figures are the displacement of a water parcel having the same velocity as measured by the current meter, and may be quite different from the actual trajectory of any parcel. The outer record showed tides (cusps), strong pulses, and a northward mean. The middle record showed strong tides (clockwise ellipses), weak northward pulses, and perhaps a weak northeastward mean. The coastal record showed strong tides, westward pulses (extending the tidal circles like a loose spring or slinky toy), and a strong westward mean. Note different scales. (S signifies the start and F the finish of each plot.) vector indicating the time, the direction away from the base indicating the direction toward flow, and the length of the vector indicating speed. The record from BC-15A at a depth of 20 m shows generally westward flow at 5 cm/sec, with higher speeds later in the record. We found that during the generally low wind speeds (10 m/sec), especially in autumn when higher winds are common and we have many records, wind and currents were much better correlated. The record segments with close correlation seemed to occur for two to four days during the passage of atmospheric low-pressure centers through the area. Spectra Except for truly dominant frequency components (, tides), it is difficult to describe the frequency distribution of the records from the plots we have presented thus far. A useful technique for doing this (and the one used to make the estimates for Table 5-3) is spectral einalysis. A time series is mathemati- cally (Fourier) transformed, so that instead of veloc- ity as a function of time, we have kinetic energy as a 22 21 AUG 76 10 SEP 76 Figure 5-4. Low-frequency flow. Low
Size: 1767px × 1132px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
