THE FORECAST PROBLEM 
2. The global extent of the persistent and systemati- 
cally changing anomalous characteristics of the general 
circulation patterns, notably in their high-index (zonal, 
poleward displacement) versus low-index (cellular, equa- 
torward displacement) features. The global, or at least 
hemisphere-wide, character of these basic index fluctua- 
tions is shown by significantly higher contemporary 
correlation between circulation indices for the entire 
Northern Hemisphere than between indices for the 
individual continental or maritime meridional quad- 
rants of the hemisphere. The statistical improbability 
of this fact of observation makes it strong evidence 
against the primary independence of the individual 
regional cellular developments of the general circula- 
tion, but it is entirely consistent with recent studies of 
energy propagation in the atmosphere [11]. 
3. The occurrence of markedly similar anomalous 
fluctuations of the general circulation pattern between 
high- and low-index characteristics, fluctuations which 
are in phase in the Northern and Southern Hemis- 
pheres, and which increase in amplitude with the length 
of the period of oscillation. This fluctuating index char- 
acter of the general circulation has paralleled the secular 
trends of climate during observational time, the greater 
changes of climate during historical time, and the ex- 
treme fluctuations between glacial and interglacial cli- 
mates during geological time. The only single physical 
factor of climatic control which can possibly be made 
to account for this entire spectrum of synoptically 
similar patterns of climatic change is that of variable 
solar activity, presumably in the ultraviolet, and parti- 
cle emissions which parallel the sunspot activity that 
is observed to be as erratically variable as the anomalous 
fluctuations of terrestrial climate [17]. 
4. The extensive evidence for the world-wide reac- 
tion of weather patterns to irregular solar disturbances, 
as shown by the anomalous fluctuations of monthly, 
seasonal, annual, and longer-period distributions of 
pressure, temperature, and rainfall in response to major 
phase changes of the sunspot cycle, and of the monthly 
mean distribution of pressure in response to anomalies 
of the monthly mean solar pyrheliometric values [1; 2; 
18, pp. 31-86]. 
5. The fact that the theoretical investigations which 
have been most successful in the physical interpreta- 
tion of the observed characteristics of the general circu- 
lation have without exception been based on some 
global or hemispheric mechanism of operation of the 
general circulation [9, 11, 12, 13, 15]. 
If it is accepted that the best line of approach to the 
basic problem of weather forecasting is by the study of 
the general circulation of the earth’s atmosphere in its 
entirety, then the general direction that this approach 
must take is rather obvious. The first concern must be 
to establish the closest possible cooperation of the 
theoretical and the synoptic-statistical meteorologists 
such that all theory and hypotheses may be influenced 
and rigidly checked by the observational facts. The pri- 
mary objectives towards which investigation should be 
directed include the determination of the primary 
energy sources and sinks in the atmosphere, as well as 
745 
of the energy transformations and transportation from 
source to sink; the establishment of the entire dynamics 
and thermodynamics of the operation of the general 
circulation as a whole between energy source and energy 
sink, and an understanding of the mechanics of inter- 
action between the zonal and cellular branches of the 
general circulation. Particular attention should be di- 
rected to the determination of the physical nature of 
the irregularly variable solar activity, to its direct 
effects in the higher atmosphere, and to the transmis- 
sion of all such direct or indirect effects to the lower 
atmosphere, notably to the troposphere in the tropics, 
where the influence of the irregular solar activity on 
the weather is most directly m evidence. 
All investigations of this general character, to be prac- 
tically effective for the physical interpretation of the 
existing states and observed changes of the state of the 
general circulation, must be guided and verified by the 
synoptic and statistical analysis of reliable global ob- 
servational weather data, and tested over as lorg a 
period as possible by extended series of past climatic 
data. Obviously, the efficient organization of a program 
such as that suggested above can be accomplished ef- 
fectively only by a strong international meteorological 
organization, for its effective prosecution in all of its 
ramifications more or less of necessity entails the fol- 
lowing procedures: 
1. The establishment of a well-integrated world-wide 
system of uniformly distributed synoptically reporting 
stations, operating under the direct control and support 
of a strong mternational meteorological organization, 
as discussed above. Since the entire research program 
should be conducted by the same central organization, 
the details of the density, character, and distribution 
of the synoptic network of observing stations must 
be planned, and occasionally modified, with an eye to 
research requirements quite as much as to practical 
current forecasting requirements. 
2. The development of more effective synoptic tools 
or techniques for the presentation and analysis of synop- 
tic weather observations on a world-wide scale. Em- 
phatically this development and standardization of syn- 
optic techniques can be effectively implemented only by 
a strong central meteorological organization, as discussed 
above. However, the development contemplated as a 
necessary part of any program of basic research in 
weather forecasting goes far beyond the mere selection 
and standardization of synoptic techniques which al- 
ready are in practice, as previously considered. This 
development should contemplate the evolution of 
basically new and improved synoptic techniques as an 
integral part of, and guided by the needs of, the basic 
research program. 
3. The establishment of one central international 
meteorological research center, under competent direc- 
tion, where leading meteorologists of all nationalities 
would be enabled to work under conditions of complete 
cooperation and exchange of ideas, with a maximum of 
readily available synoptic data and the necessary 
amount of clerical assistance. In this manner it should 
be made possible for the meteorologists with the most to 
