The relationship between the magnitude of tjq and the net volume 

 volume transport through the ports discussed in the simulation of 

 hurricane Allen is reinvestigated. Figures 91 through 93 show the 

 barotropic volume transport through the Florida port and Yucatan 

 Strait, and the difference of the two components obtained from the 

 HURl, HUR4 and HUR25 simulations, respectively. It can be seen from 

 the figures that the larger the net volume transport through the 

 ports the larger the magnitude of rjQ. This result should be expected 

 based on continuity. The first maximum of the total volume transport 

 for HUR4 is approximately 10 x 10^ m^/s which is about a factor of 2 

 larger than that produced by HURl. The same ratio of maximum tjq 

 obtained from the two storms provide quantitative evidence for 

 relating t)q to the net periodic transport. Note that the volume 

 transport from the HUR25 simulation and the associated tjq is very 

 small. The initial position of this storm and associated wind field 

 gives smaller flows through the two openings as compared to HURl and 

 HUR4. 



The average period of the net periodic volume transport in each 

 case is about the same as the period of the corresponding tjq signals. 



o 



The rjQ signal however, is approximately 90 out of phase (lag) with 

 the total periodic transport. This result resembles the uninodal 

 seich in a one dimensional channel. However, the ubiquity of the r?Q 

 signal in the hydrographs around the Gulf implies that the net 

 periodic transport acts like a single port forcing and excites the 

 entire Gulf proper to oscillate with a node at the port. In other 

 words, the tjq oscillation is a Helmholtz mode excited by the net 



152 



