EM 1110-2-1100 (Part II)
(Change 1) 31 July 2003
Duration-limited wave periods
Thus, parametric models do not work well for all hurricanes, but do provide accurate results when the
following criteria are met for an interval of about 12 to 18 hr prior to the application of a parametric model:
Hurricane intensity (maximum velocity) is relatively constant.
Hurricane track is relatively straight.
Hurricane forward speed is relatively constant.
Hurricane is not affected by land or bathymetric effects.
No strong secondary wind and/or wave systems affect conditions in the area of interest.
(4) In certain situations, where there is a lack of detail on the actual characteristics of a hurricane (such
as in hurricane forecasts, older historical storms, hurricanes in some regions of the world where
meteorological data are sparse), parametric models may provide accuracies equal to those of spectral models,
provided that land effects and bathymetric effects are minimal. However, even when these criteria are met,
situations where secondary wind and/or wave systems can seriously affect wave conditions in an area should
be avoided. Examples of this occur when large-scale pressure gradients (monsoonal or extratropical)
significantly affect the shape and/or wind distribution of a hurricane. Winds and waves in such a storm will
not be distributed in a manner consistent with the assumptions made in this section.
Meteorology and Wave Climate