SECT. 2] 



LARGE-SCALE INTERACTIONS 



243 



r (km) 

 (C) 



Fig. 70. Some comparisons of moderate hurricane model with observed hurricanes. (After 

 Malkus and Riehl, 1960, Figs. 2, 3 and 4.) 



(a) Upper graph is low-level wind-profile as function of radial distance from storm 

 center in km. Solid line computed from model (Table XVII). Circles represent peak 

 wind speed at each radius in hurricane Carrie, 1957, while the crosses denote the 

 radial average for the same storm. Lower graph is surface pressure as function of 

 radial distance from storm center in km. Solid line computed from model (Table 

 XVII). Profile with crosses observed from hurricane Carrie, 1957; two isolated 

 circles from Daisy, 1958. 



(b) Upper graph is mass inflow as function of radius in km. The quantity plotted is 

 Ur'T in knots times degrees latitude. Solid line computed from model (Table XVII). 

 Long-dashed curve with x's computed from wind observations in hurricane Carrie, 

 1957 ; short-dashed curve computed from wind observations in hurricane Daisy, 1958. 

 Lower graph is radial velocity u^ (in knots, here positive inward) as function of radius 

 in km. Solid curve computed from model, x-ed curve measured in Carrie and short- 

 dashed curve measured in Daisy. 



(c) Surface-shearing stress (dynes/cm^) versus radius in km. Co-ordinates both on 

 logarithmic scale. Solid curve from model moderate storm (Table XVII) ; dashed 

 curve from momentum budgets calculated by Palmen and Riehl (1957) for mean 

 hurricane data. 



are predicted i for the moderate storm; thus stresses exceeding 150 dynes/cm^ 

 are inferrable for extreme hurricanes, up more than two orders of magnitude 

 over normal. This is probably the highest wind stress experienced by the ocean 

 and it is, fortunately, only exerted over small regions and times. 



1 The highest marine stress to date measured by the aircraft method was 5 dyne/cm^ at 

 500 ft in a 50-knot wind of an extra-tropical storm near Bermuda. 



