EM 1110-2-1100 (Part II)
(Change 1) 31 July 2003
Figure II-2-11. Key to plotted weather report
EXAMPLE PROBLEM II-2-4
FIND:
The estimated overwater wind speed at a site over 10 miles from shore, given that the air-sea temperature
difference is near zero (∆T.0).
GIVEN:
A wind speed of 7.5 m/s at an airport location well inland (at the airport standard of 30 ft above ground
elevation).
SOLUTION:
From Figure II-2-7 the ratio of overwater wind to overland wind is about 1.25. In the absence of information
to calibrate a local relationship, multiply the 7.5-m/s wind speed by 1.25 to obtain an estimated overwater wind
speed of 9.4 m/s. It should be recognized that the 90-percent confidence interval for this estimate is approximately
15 percent. It may be desirable to include this factor of conservatism in some calculations. However, at this short
fetch, there is already conservatism due to the lack of consideration of wind speed variations with fetch.
II-2-18
Meteorology and Wave Climate
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