DISCUSSION 
the monsoon region, in the savannas. There, it 
will go up and down many times before it leaks 
out east of Ethiopia and aloft, and perhaps also 
somewhat through the southern front. This pic- 
ture holds good not only for July, but for all the 
time from April or May until October. In fact, 
the tropical front passes Kharthum (15°N.) in 
the middle of May on its way north, and passes 
the same place again moving south in the middle 
of October. 
In the future, when we have economical 
atomic energy, we can even have factories evapo- 
rating sea water, thus enriching the southwest 
monsoon with humidity, and let the monsoon 
itself carry and distribute the humidity over the 
region, if huge irrigation plants prove too costly 
to construct. Moreover, the present cooling ef- 
fects within the monsoon area will be intensified 
both indirectly by increasing cloudiness, shutting 
off the sunshine, and indirectly by the increased 
precipitation. Then the northern tropical front 
will move north a little. How much, we do 
not know, but it is quite likely to move north 
until it reaches a position where it can not go 
further north for reasons of the general plane- 
tary dynamics. If you now have increased 
amounts of humidity, this project of Dr. Des- 
sens is very useful because then it will pay even 
more to utilize the latent instability for releasing 
even more showers. So, I think these two proj- 
ects might be able to cooperate nicely in the fu- 
ture when we have more sources of cheap en- 
ergy. 
Mr. Jerome Namias—It is refreshing to see a 
man of Dr. Bergeron’s stature becoming inter- 
ested in weather modification problems. Sup- 
porting his discussion, I want to bring out a 
thought which may have been overlooked in 
dealing with this problem. In the first place, of 
course, the problem will not achieve a desirable 
solution until the numerical part of it is solved, 
so that we know exactly the sequence of events 
after we have treated weather or cloud condi- 
tions artificially. Now, in this conference, where 
all sorts of ideas are set forth, we may consider 
possibilities which extend further into the fu- 
ture. Presently, a science is emerging from re- 
search in extended forecasting which deals with 
‘tele-connections, the long-distance interactions 
of weather regimes where one or more effects in 
one area affect other areas in a very dramatic 
way. One of the aims of long-range forecasting 
is to find such areas which are in resonance with 
other areas. It appears possible that certain 
401 
forms of the general circulation exist which are 
rather precariously balanced, and which might 
be influenced if man acquires the amounts of 
energy commensurate with what is believed to be 
necessary and, of course, knows how and where 
to apply it. Then those people who have worked 
many years on these problems, namely, those 
who have experience in extended long-range 
forecasting, should be consulted as to the weak 
spots and precariously balanced states in the at- 
mosphere; that is, the circulations that are on 
the verge of doing one thing or another. Here 
is an example: The weather over the North 
American continent, and particularly the United 
States, is greatly influenced by a special type of 
intense cyclone which often forms in the Gulf 
of Alaska. If it is there, it tends to bring about 
one type of weather through its influence on the 
large-scale circulation over North America; if it 
is not there, another quite different, meteorologi- 
cally opposed, type occurs. The development of 
this cyclone is very explosive. It takes place 
rapidly, and is sensitive to the general upper-air 
flow. If this flow comes from Alaska (with ex- 
treme cold air heated over the Gulf) the rapid 
heating and distortion by the coastal ranges in- 
duces strong cyclonic vorticity. Since this ap- 
pears to be a rather sensitive mechanism, it may 
lend itself to artificial control. I therefore feel 
that synoptic studies of the general circulation 
and its weak spots should be earried on right 
now, so that if the day comes when commen- 
surate supplies of energy are available, we will 
be in a better position to undertake projects of 
large scale weather modification. 
Dr. Bergeron—May I just declare that I am 
more than in agreement with my friend on these 
points. I have always thought of these critical 
thresholds in the general circulation, how the 
pattern may Just jump over from one preferred 
shape to another; and that there may be rather 
small quantities of energy needed. And, of course, 
I am also quite aware that dynamists, the long- 
range forecasters, and those working with nu- 
merical computors are the people to take care of 
certain important sides of that problem. The 
reason I chose that part of the world (North 
Africa) was, that down there the problem seems 
to be even simpler, because you do not need to 
change very much, just a little increase in the 
humidity, and that would be perhaps the best 
region in the world at present where one could 
utilize the humidity directly without too much 
los: 
7] 
