EM 1110-2-1100 (Part II)
30 Apr 02
WIS ATLANTIC REVISION 1956 - 1975
LAT: 36.00 N, LONG: 75.25 W, DEPTH: 37M
OCCURRENCES OF WAVE HEIGHT AND PEAK PERIOD FOR 45-DEG DIRECTION BANDS
STATION: 55
( 67.50 - 112.49) 90.0 DEG
Tp (sec)
Hmo (m)
TOTAL
3.0-
5.0-
7.0-
9.0-
11.0- 13.0- 15.0- 17. 19. 21.0-
0-
0-
4.9
6.9
8.9
10.9 12.9 14.9 16.9 18.9 20.9 LONGER
0.00 - 0.99
381 784 2655 1809 667
267
46
11
4
.
6624
1.00 - 1.99
58 1344 1327 1197 990
347
48
8
1
.
5320
2.00 - 2.99
.
44 429 180 161
67
.
.
.
.
881
3.00 - 3.99
.
.
55 156
54
30
5
.
.
.
300
4.00 - 4.99
.
.
3
64
33
9
5
.
.
.
114
5.00 - 5.99
.
.
.
6
21
4
2
.
.
.
33
6.00 - 6.99
.
.
.
.
6
5
.
1
.
.
12
7.00 - 7.99
.
.
.
.
.
3
2
.
.
.
5
8.00 - 8.99
.
.
.
.
.
7
3
.
.
.
10
9.00-GREATER
.
.
.
.
.
.
.
.
.
.
0
Total
439 2172 4469 3412 1932
739
111
20
5
0
13299
Figure II-8-15.
Wave climate summary (Hubertz et al. 1993)
(3) Storms.
(a) Storms are a natural part of the wave climate at a site. On the order of 20-50 storm events can be
expected at a site during a year of record. The upper portion of the distribution of Hs is due to storms, either
local or distant. Much of the storm wave climate is fairly consistent from year to year. Three years of data
usually suffice for a reasonable representation of the storm portion of wave climate (excluding extreme
events). Large storm events usually dominate any secondary wave systems present, and the sea state can be
well-represented by one Hs, Tp, and θp parameter set. Tropical storms are generally a concern only in the
extreme portion of wave climate, if at all, since even the more exposed sites are rarely affected by them.
(b) Some areas can experience changes in climate that systematically affect the incidence and intensity
of severe storm waves over a time period of months or years. The reasons for climate change are not always
easily understood. Short-term climate variation can be related to deviations from characteristic upper air flow
patterns or large-scale ocean current patterns that persist over at least one storm season. One documented
~
example is the influence of the El Nino-Southern Oscillation climatic anomaly on the occurrence of extreme
waves along the California coast (Seymour et al. 1984). Both tropical and winter storms are affected. Long-
term systematic climate changes can be generated by factors such as local subsidence and global temperature
change. An example of long-term change is the increasing trend in annual mean significant wave height off
the southwest tip of England as measured over a 25-year period at Seven Stones Light Vessel (Carter and
Draper 1988).
(4) Persistence of high and low wave conditions.
II-8-30
Hydrodynamic Analysis and Design Conditions
Previous Page
