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Chapter 1 Introduction The monitoring of o w surface currents is an important coastal management problem in the ares of ashore oil development. Gsheties research and maaward appli- cations. O'i spill trajectories from tankers and offihare fields are lmgely determined by the motion of the surface layer. The tr-port of nutrients and Bh larvae require knowledge of water mwement for fisheries preservation research. Timely and am- rate surface ment data is & required for search and rmue models to optimize the size of search region zones when traekhg drifting vessels. However, the surface current measurements obtained by conventionsl devi- such as furrent meters and hiners may not give the required spatii or temporal detail to be optimal for the ahwe purposes. In addition. the lo*ties mciated with deploying these devices is difficult. t i consuming and very expensive. An almtiw to these in sihr tffhniqum is provided by H&h Requency (HF) radar using the ground wave mode of propagation. The HF hand ranges fmm about 3 to 30 MHz, and at these bequendes the relatively high conductiviQ of the sea water enables the radar tr-mission to extend well beyond the line-of-sight range experienced by traditional microwave season. Because of the HF band's dekametric wavelengths, the dominant interanion is with the energy carrying long-wavelength gravity waves. Thm waves are usually of mneern to &shore developers for structural de@ purpcees. Howwer, the analysis of -uttered radio warn fmm these ocean
wae is also useful for the estimation of surf- layer physical mography and, in particular, surface currents. Scattermg of eiectromsgoetie w ae hm rough surfaces is a classical problem in radio science, and the scattering of surf- or pund waves hm the sea is a special -. If ones m e s that theom hurfaeeem be represented by a threedimensional Fourier tramform, then the scattered wave energy can be modelled. Using this a p proach, the theory of ground wave radar, h m an oceanopphic perspective, has been well establhed. Barrick [I] formulated the ht and second order radar cr- sections of the acean surf-. Mare recently, Walsh and Donnelly [2] have addressed hmdamental eieekonmpetic scattering and propagation problems relating to HF ground wave radar (GWR) operation in an oeean environment. The latter work hz led to the development of new radar crcswenions of the ocean surf- to thrd aider (Walsh et el. (31). These efforts have provided the bais for the fmherance of GWR techlogy and haw led to signi6eant ad-- in the use of HF Doppler radar. for the remote sensing of various oceanic surface parame-. In pwticular, narmw- and broad-beam arrays, operating in the ground wave mode, have been sue-fully employed in the determination d oeean eUTTMb, surface winds, and directional and noodirectional wave parameters (Hickey and Khan 141, Hall and Walsh [S], Gill and Walsh [6]). Such initiatives have been spurred on by the the fact that HF radars, as compared to in rttudevices such as current meters or wave buoys, are able to provide comprehensive synoptic oeeanopphic information over a v w 1- area. HF radar surface current measurements are representative of the total current (i.e. the interactive sum of g-tropic, tidal, wave, and wind generated components). AU HF radars indirectly measure the component of the average current lying along the ~adar Line of sight. For example, if the radar is directed at a patch of the oeean surface, ~t will o b the component of the surface current along the direction of obenatim. This is illustrated in Figure 1.1 where a uniform current is Rowing
Page 1: CENTRE FOR NEWFOUNDLAND STUDIES TOT
Page 6 and 7: Abstract Esrlm=r#oo of ocean surf-
Page 8 and 9: Acknowledgements Quite a number of
Page 10 and 11: Contents Abstract List of Figures L
Page 12 and 13: 5.2 Direct Radial Surface Current C
Page 14 and 15: 3.4 System architecture of Cape Rae
Page 16 and 17: List of Tables 5.1 Summary of stati
Page 18 and 19: List of Symbols d : Distance irom r
Page 22 and 23: southward. In t k example the same
Page 24 and 25: 1.2 Conventional Methods for Measur
Page 26 and 27: iceberg motion, a better relationsh
Page 28 and 29: magnitude of the radid component is
Page 30 and 31: Rice 1241, Barrick [I] developed an
Page 32 and 33: ange broad and narrow-ham systems (
Page 34 and 35: the shon-r- radar is quite diEerent
Page 36 and 37: of a chapter. Thig dso provides an
Page 38 and 39: 2.2 Radial Surface Currents 2.2.1 T
Page 40 and 41: Figure 2.1: Radw Spectrum (solid li
Page 42 and 43: intervals of Ar and A.9, where thee
Page 44 and 45: Figure 2.3: Wan Q is mbdivided into
Page 46 and 47: The abwe system of equations is swe
Page 48 and 49: Chapter 3 Experimental Data 3.1 Int
Page 50 and 51: e built at other eoastd sites such
Page 52 and 53: Since the mean currents within mast
Page 54 and 55: Figure 3.4: System architecture of
Page 56 and 57: spatid variability and to check sys
Page 58 and 59: oth of these techniques ean then be
Page 60 and 61: the dominant, or 9-, peaks of the s
Page 62 and 63: modelled, since they are known quan
Page 64 and 65: Sine the drifter estimates m e mnst
Page 66 and 67: 4.6.2 Selection of Algorithmn Param
Page 68 and 69: subtended by the b- increases in sb
Page 70 and 71:
simplib the analysis by converting
Page 72 and 73:
for then beams is therefore 3, 5 an
Page 74 and 75:
with the graphs are from a linear r
Page 76 and 77:
Fiere 5.2: Scattergrams of radid su
Page 78 and 79:
Table 5.2 that the SNR eases of 10
Page 80 and 81:
m-ments deliwred by radar and buoys
Page 82 and 83:
Figure 5.6: Scattergrams of simulat
Page 84 and 85:
Figure 5.7: Scattergrams of -tor me
Page 86 and 87:
size. In other words, the algorithm
Page 88 and 89:
tem, which is a programmable fsture
Page 90 and 91:
Radii vetocify [cws) - Radar Figure
Page 92 and 93:
ocean surface m nts where the curre
Page 94 and 95:
Chapter 6 Conclusions 6.1 Direct Ra
Page 96 and 97:
gential component estimate, wen wit
Page 98 and 99:
One of the goals of this thesis has
Page 100 and 101:
Future work dl also deal with the f
Page 102 and 103:
[I4 D. Diemand, E. Faemer, and J. B
Page 104 and 105:
(461 D. Barriek, M. Evans, and B. W
Page 106 and 107:
DATE (LOCAL) EVENT Comments shorn 6
Page 108 and 109:
TIME - DATE (LOCAL) EVENT Comments
Page 110 and 111:
The tape was mated by using the DEC
Page 112 and 113:
Where DATLOG - Array of 32x3 bytes
Page 114 and 115:
Appendix C Catalogue of the NRSL Ra
Page 116 and 117:
Date (1992) 11/11 12/11 13/11 14/11
Page 118 and 119:
Time I FFT 1 - Date 01/11/92 02/11/
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