Radiation and Dispersion of Internal Waves 



It is significant to note that Cg^ is always opposite in sign to c^, and Cg /cg^ = 

 Cy/c^. Since Cg gives the direction and speed of propagation of wave energy, 

 this means that c, Cg and e^ are always coplanar, and a wave group propagates 

 with its vertical component in the direction opposite to the phase velocity of 

 individual wavelets. Furthermore, Cg has the magnitude 



= A (cos^e + e2 sin^e*) 



(50a) 



Hence for fixed k, c > c for o < 6 < 

 And 



n = ec , 



cot" ' x/l- e2, and c < dor e <e < 77/2. 



Cfl = A cos 



(50b) 



These basic features are illustrated in Fig. 3. These waves may be superim- 

 posed to give standing cellular waves, such as can be observed in a heated room. 

 The amplitude of these waves increases upward, proportional to e^^, so that the 

 energy in each cell is the same. 



Fig. 3 - Dispersion of gravity waves 

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