A more widely used model was given by Myers (1954). A concise mathe- 

 matical description of this model is given by Harris (1958) as follows: 



(3-28) 



'o)? 



R -^ 



e , (3-29) 



where p is the pressure at a point located at a distance r from the 

 storm center, p is the central pressure, p is the pressure at the 

 outskirts of the storm, p^ is the density of air, and U„p is the 



gradient wind speed. Agreement between this model and the characteristics 

 of a well-observed hurricane is shown in Figure 3-33. The insert map gives 

 the storm track; dots indicate the observed pressure at several stations in 

 the vicinity of Lake Okeechobee, Florida; the solid line (Figi 3-33a) gives 

 the theoretical pressure profile fitted to three points within 50 miles of 

 the storm center. The corresponding theoretical wind profile is given by 

 the upper curve of Figure 3- 33b. Observed winds at one station are indi- 

 cated by dots below this curve. A solid line has been drawn through these 

 dots by eye to obtain a smooth profile. The observed wind speed varies in 

 a systematic way from about 65 percent of the computed wind speed at the 

 outer edge to almost 90 percent of the predicted value near the zone of 

 maximum wind speed. Reasonably good agreement between the theoretical and 

 observed wind speeds has been obtained in only a few storms. This lack of 

 agreement between the theoretical and observed winds is due in part to the 

 elementary nature of the model, but perhaps equally to the lack of accurate 

 wind records near the center of hurricanes. 



Parameters obtained from fitting this model to a large number of storms 

 were given by Myers (1954). Parameters for these other storms (and for 

 additional storms) are given by Harris (1958). Equation 3-29 will require 

 some form of correction for a moving storm. 



This model is purely empirical, but it has been used extensively and 

 it provides reasonable agreement with observations in many storms. Other 

 equally valid models could be derived; however, alternative models should 

 not be adopted without extensive testing. 



In the northern hemisphere, wind speeds to the right of the storm 

 track are always higher than those on the left, and a correction is needed 

 when any stationary storm model is being used for a moving storm. The 

 effect of storm motion on the wind field decreases with distance from the 

 zone of highest wind speeds. Thus the vectorial addition of storm motion 

 to the wind field of the stationary storm is not satisfactory. Jelesnianski 

 (1966) suggests the following simple form for this correction, 



^SM « = :^rh ^F . C3-30) 



rv. T r 



3-56 



