. Collected reprints, Essa Institute for Oceanography. Oceanography Figure 23.—Same as figure 22 with bottom slip s equal to ft. Figure 24.—Same as figure 21, for hurricane Donna. Eddy and slip coefficients were used in the computations. the computed crests, , model time. Notice that the computed surge without bottom stress has a directly- generated crest that agrees with the observed crest but the computed resurgences are too large in amplitude; this suggests the need of a dissipating mechanism. The computed crests at time 4 hr. are the result of initialization
. Collected reprints, Essa Institute for Oceanography. Oceanography Figure 23.—Same as figure 22 with bottom slip s equal to ft. Figure 24.—Same as figure 21, for hurricane Donna. Eddy and slip coefficients were used in the computations. the computed crests, , model time. Notice that the computed surge without bottom stress has a directly- generated crest that agrees with the observed crest but the computed resurgences are too large in amplitude; this suggests the need of a dissipating mechanism. The computed crests at time 4 hr. are the result of initialization phenomena due to rapid storm growth to maturity; a slower growth would suppress this precursor. We wish to determine a value for an eddy viscosity coefficient that suppresses the resurgences computed with- out bottom stress but at the same time does not affect the directly generated crest. To do this we first digress to consider the effect of different eddy coefficient values on the directly generated surge. We consider at this time the case of a zero slip coefficient (no bottom stress) and plot the computed surge profile generated by a fast moving (30 ) standard storm traveling normal to the coast in a standard basin (fig. 22). We consider further the case of an infinite bottom slip coefficient (no bottom current) and bracket the no bottom stress profile in the figure with profiles computed with eddy coefficients that range through an order of magnitude. The peak surge decreases monotonically with increasing eddy values for the range shown in the figure. Notice that small values of the eddy coefficient give a directly generated crest larger than com- putations without bottom stress. We now arbitrarily choose a middle value for the eddy coefficient of c= and recompute the surge off Atlantic City. For v=.25 , figure 21 shows that the directly generated crest is not significantly affected but the re- surgences are dampened too strongly; there are a
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