310 THE FUTURE OF ARID LANDS 
Need of Basic Research in Atmospheric Physics 
Much basic work remains to be done in the exploratory phases 
of experimental meteorology. Despite the extensive and wide- 
spread commercial cloud seeding which has been underway for 
the past 4 to § years, certain aspects of the problem have been 
seriously neglected. 
Perhaps the simplest and yet one of the most neglected fields 
has been the cloud survey. Despite some localized studies (3, 7, 17, 
22) great gaps remain in our knowledge of these fundamental 
features of the lower atmosphere. There has been a tendency in 
the past to assume that cloud behavior was similar in most places. 
However, a little study in the field of what may be called ‘‘com- 
parative cloud structure” quickly demonstrates the danger of 
such extrapolation. 
While it is possible to discover similarities in the clouds which 
form near and over the Hawaiian Islands and those of Puerto Rico, 
a cumulus forming in such trade wind regions is far different in 
properties, appearance, and precipitation mechanism from one 
over a mountain bordering the Rio Grande of New Mexico. In 
turn these two will have characteristics entirely different from a 
cumulus forming near the Priest River Valley of northern Idaho. 
Fortunately, cloud surveys are becoming more common. Recent 
studies in the midwest (g), Puerto Rico (8), Sweden (1g), and the 
northwestern United States (2) have established techniques 
which may be adapted to local conditions and available personnel 
and equipment. These procedures vary from exact measurements 
of many individual clouds to the patterns of cloud systems forming 
localized thunderstorms. 
Supplementing these local observations is the current prepara- 
tion of what might be termed a dynamic cloud atlas. Time lapse 
cloud movies are being obtained in many parts of the world under 
sponsorship of our Foundation (28). 
A widespread photographic coverage of cloud systems in the 
United States and its surroundings is underway through the co- 
operation of such groups as the U.S. Forest Service, the National 
Park Service, various universities, the Boeing Airplane Co., 
private industrial meteorological organizations, the U. S. Weather 
Bureau, and cooperative individuals. In addition, similar cloud 
