APPLIED CLIMATOLOGY 
commodate the ever-increasing population of the world, 
this type of investigation remains one of the most 
pressing tasks of applied climatology. 
Perhaps the greatest challenge to the ingenuity of 
climatologists, however, is the problem of using climatic 
data in the field of human pathology—the question of 
the influence of climate on disease. There is little 
doubt that the climatic environment contributes to the 
spread of certain diseases and can also help in the 
treatment of diseases. The simplest of the many prob- 
lems in this field is the selection of health resorts for the 
fatigued yet not completely diseased body. The results of 
much of the work discussed in the preceding paragraph 
have led to the establishment of climatic requirements 
for resort places. No final agreement has been reached 
on what constitutes a climatic resort, although good 
proposals have been advanced [61]. Climatic pre- 
requisites for resorts for persons afflicted by various 
diseases which respond to climatotherapy raise even 
more complicated questions. Beneficial and adverse en- 
vironments have been cited for a large group of patho- 
logical conditions. Among them are the respiratory 
ailments such as bronchitis, asthma, tuberculosis, and 
diseases of the circulatory system. As long as indica- 
tions and contra-indications are not agreed upon by the 
physicians, the climatologist can only occasionally lend 
a helping hand, although some exceedingly fine climato- 
logical studies have been prepared for climatothera- 
peutic purposes [25-27, 52]. 
Even though the health of the population in general 
is improving and better drugs and other therapeutical 
devices, including climatic chambers in hospitals, are 
rapidly being developed, the problem will remain alive. 
Progress in health conditions has led to a spectacular 
increase of old people. The aged body cannot compen- 
sate for the climatic stresses as well as the young 
one can. Gerontologists have repeatedly pointed out 
that life expectancy increases in areas with favorable 
climates. What constitutes a favorable climate in this 
sense is at present ill-defined, although certain re- 
gions of the world have literally developed into retire- 
ment eldorados. 
Climatic influences on the incidence of certain dis- 
eases have been claimed ever since Hippocrates. Modern 
medical science has accepted some of these claims and 
has rejected others. But in many cases it has not 
applied the refined tools of modern physical science to 
establish undisputed facts. The basic idea of climatic 
influence on many diseases is generally taken for 
granted; the details of the mechanism of this influence 
are ill-understood, matters of opinion, or simply ig- 
nored. It is uncertain which diseases are influenced by 
climatic conditions and which are the specific climatic 
elements involved in each case. It is further uncertain 
whether these fluences are mainly on the causative 
agents, bacteria and virus, or on the disease vectors, 
insects and other carriers, or on the human body. It is 
quite likely that a concerted effort by teams of phy- 
Sicians, statisticians, and climatologists could solve 
981 
many of the riddles in this field. (Pertinent literature is 
extensive. See [8, 13, 67, 73].) 
Techniques of Applied Climatology 
In the solution of applied climatological problems the 
technique will vary with the degree of complexity. 
Three major parameters enter into every problem: 
1. Climate, composed of the various weather 
elements. 
2. Space, consisting of the surface and upper layers 
of the atmosphere. 
3. Time, comprising the series and sequence of 
weather observations. 
Each of these parameters can appear in the problem 
either as a simple or as a complex element. In other 
words, the climatic factor can involve one weather 
element or many. Space can mean a single point, 
several points, or an area. Time may enter only in the 
restricted sense that the observations cover an interval 
of time or the problem may pose specific time limita- 
tions in terms of cumulative effects or conditioning of 
subsequent events by preceding situations. These con- 
siderations lead to various combinations of the three 
parameters (Table III). 
TasiE III. Comprnation or PARAMETERS IN 
Ciimatic PROBLEMS 
Space Time Climate 
Single element 
Simple series 
Multiple element 
Single point 
Single element 
Complex relation 
Multiple element 
Single element 
Simple series 
Multiple element 
Multiple point or 
area 
Single element 
Complex relation 
Multiple element 
Each of the combinations listed in Table III can be 
illustrated by examples. These can serve to elucidate 
the problem and show what techniques have been 
employed to furnish the answers to practical questions. 
For some of the combinations many examples are ayail- 
able, for others only a few have so far been investigated. 
Some of the solutions are adequate, others are only 
makeshift. 
Single Point—Simple Time Series—Single Climatic 
Element 
The classical problem in this category is that of 
insurance against an adverse weather factor. The most 
common weather risks for which insurance protection is 
offered are hail, rain, and violent windstorms. 
According to Roth [72], hail insurance on crops has 
been written in Europe for over a century and in the 
United States since 1880. Insurance rates must be 
based on the frequency and severity of hailstorms. 
Data on these storms during the growing season de- 
termine the risk. At present, risks are calculated for 
