646 
termination of divergence and vertical velocity by the 
kinematic method would seem possible in forecasting 
techniques. The advantage of the kinematic method 
is the possibility of computing vertical velocities within 
only a few hours after the time to which they apply. 
This and the rather indecisive results of the earlier 
forecast studies might make it desirable in the future 
to study forecasting techniques based on vertical 
velocities. 
Another possibility, which has been only partially 
tested thus far, is the application of the vorticity 
equation (10) to the forecast of changes of vorticity 
from observed divergence. 
So far, systematic work on vertical velocities has 
been restricted to middle latitudes in the Northern 
Hemisphere. It is quite possible that the observed 
relation between vertical and meridional velocities, for 
example, is not valid everywhere. Studies in other 
parts of the world are desirable in order to determine 
whether there exists a general relation between vertical 
and meridional motion or vertical velocity and advec- 
tion. Moreover, a study of the relation between verti- 
cal velocities, divergence, and weather is desirable in 
other sections of the globe. 
In general, a better understanding of vertical mo- 
tion will presumably arise out of the work which Dr. 
Jule Charney and his collaborators are domg at The 
Institute for Advanced Study on numerical forecasting 
based on the physical equations. 
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