Geoscience Reference
In-Depth Information
LAKE GEORGE
AUSTRALIA
N
Sydney
Canberra
Melbourne
Experimental
site
2 km
Figure 3.6 Location of the Lake George field experiment site. Figure is reproduced from
Babanin
et al.
(
2001
) by permission of American Geophysical Union
extremely flat, Lake George is an ideal location to study
in situ
fetch-limited behaviour of
wind-generated waves in a constant finite-depth environment.
The predominant wind directions at Lake George are westerly and north-westerly, and
therefore the site was located near the eastern shore as seen in
Figure 3.6
. Under typi-
cal meteorological conditions the range of values of inverse wave age
U
10
/
c
p
and non-
dimensional depth
k
p
d
expected at the site were 1
.
0
<
U
10
/
c
p
<
3
.
5 and 0
.
7
<
k
p
d
<
2
0, respectively. At the extreme end, wind-wave records at wind forcing as strong as
U
10
/
.
8 were taken (
Donelan
et al.
,
2006
;
Babanin
et al.
,
2007b
). Here,
k
p
is the
wavenumber corresponding to the spectral peak, and
d
is the mean water depth. For
linear waves these experimental conditions are representative of intermediate-depth
wind seas.
The experimental site included an observational platform with a shelter to accommodate
equipment and researchers during observations (see
Figure 3.7
for a general view). The
platform was located 50m from shore and was accessible via an elevated walkway. The site
was equipped with a comprehensive instrumentation system for the study of finite-depth
wind-wave energy sources and sinks. The measurements described here were made from
a 10m-long measurement bridge located to the side of the platform (
Figure 3.7
shows a
general view). Approximately half-way along the bridge, the water surface elevations were
measured using an array of capacitance gauges (see also
Figures 3.2
,
3.3
). A hydrophone
was located directly below the wave probes and sensed the noise generated by individ-
ual breaking waves. The water surface around the capacitance array and hydrophone was
c
p
≈
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