APPLIED CLIMATOLOGY 
flights optimally adapted to weather conditions. A 
flight operation will be the more economical the better 
the weather conditions are at the terminals and over the 
route. Poor terminal conditions, as expressed by weather 
minimums of combined ceilings and visibilities, pro- 
hibit or delay take-offs and landings. Hazardous con- 
ditions en route, such as severe icing and severe tur- 
bulence due to fronts and thunderstorms, may require 
detours or delays and hence are not conducive to the 
maintenance of a smooth flying schedule. A good flying 
day can be defined in terms of absence of such limiting 
weather conditions in sequence at the take-off point, en 
route, and at the landing terminal. This sequence of 
events cannot be established readily by spot observa- 
tions. But it can be obtained on sequences of synoptic 
weather maps. Statistics of the annual variation of good 
and poor flying days, the change from year to year, at 
least in terms of largest and smallest number, will give 
a planner the weather factor for a decision on whether 
or not a specific air route can be operated profitably. 
The identical technique was applied to logistic and 
other planning problems during World War II. Strategic 
bombardment operations were a case in question. The 
limiting weather conditions for take-off and landing in 
friendly territory, the route conditions, and the avail- 
ability of targets for visual or blind bombing entered the 
picture. This application of synoptic-climatic tech- 
niques has been discussed in more detail by Jacobs 
[45, pp. 20-22]. 
This type of study for airline operations can be con- 
siderably refined by considering, for example, diurnal 
variations of limiting conditions for each hour at the 
terminals and en route. There is no reason to elaborate 
on this because every meteorologist knows that during 
certain times of the day in various seasons limiting 
conditions are particularly prevalent at certain air- 
ports. It is elementary to expect higher frequency of 
dense fogs in the hours before sunrise. Also the high 
summer frequency of fogs in areas like Newfoundland is 
notorious. The climatic analysis can place such knowl- 
edge on a systematic basis. The same applies to the 
seasonal variations of air trajectories. These can be ob- 
tained from the upper-level synoptic maps and used for 
laying out the most advantageous routes over great 
distances in accordance with the principles of pressure 
pattern flying. 
Additional Unsolved Problems 
The foregoing review of the state of the art of applied 
climatology had to point to a great variety of only 
partially solved problems. In fact, each new appli- 
cation will require its own specific solution. In many 
respects this part of the Compendium of Meteorology 
is a series of confessions of ignorance. 
We have already pointed out in sufficient detail the 
need for new types of observations, many of which re- 
quire new instrumental approaches. The requirement 
for statistical solutions better adapted to the specific 
problems has also been discussed. These are not the only 
deficiencies. The classical methods of summarization 
989 
and graphical presentation need radical overhauling in 
many respects [55]. Some very remarkable advances of 
graphical and pictorial presentation of climatic data, 
growing out of wartime experiences, have been placed 
in the scientific record [45, pp. 44-51). 
Yet we still lack adequate methods for multidimen- 
sional representation of data. We need more nomo- 
graphic charts to simplify the presentation of complex 
relations and to allow for a quick solution of empirical 
equations. 
We have indicated that, in contrast to classical cli- 
matology and climatography, applied climatology is a 
broad, two-way meeting ground between the synoptic 
meteorologist and the climatologist. A fruitful field for 
joint efforts lies in the methods of atr-mass climatology. 
There has been insufficient space to discuss these in 
detail here. This approach, however, has shown in- 
creasing promise for problems of bioclimatology [24, 
33, 56, 62]. It is likely that further work along this line 
can find useful applications. 
Other advances in applied climatology are intimately 
tied to progress in microclimatology. The research needs 
in this field have recently been presented by Baum and 
Court [11]. Their very pertinent remarks can be sum- 
marized as follows: There is need for standardization 
of microclimatic procedures and equipment. More 
measurements are needed on the vertical distribution 
of the usual climatic elements in the boundary layer 
over various forms of terrain and vegetation. Coin- 
cidentally, measurements of the following factors should 
be made: 
. Temperature gradient in the soil. 
Soil conductivity as a variable quantity. 
Insolation, direct and diffuse. 
Atmospheric radiation. 
Terrestrial radiation. 
Eddy conductivity in the air. 
. Evaporation. 
As basic problems Baum and Court propose studies and 
causal understanding of the heat balance at the surface 
of the earth, the existence and extent of laminar layers 
near the surface, and the interrelation of microclimatic 
factors and evaporation. 
Lastly, it should again be stressed that applied cli- 
matology should be in each instance a cooperative 
venture. It deals with borderline fields. Climatology is 
on one side; on the other side are a great many other 
disciplines (medicine, ecology, agronomy, hydrology, 
pedology, architecture, strategy, business management, 
and various phases of engineering). The solutions to 
the many joit problems can best be found by team- 
work. 
St Ee Fo 
Appendix 
, Table VIII lists areas of practical problems in ap- 
plied climatology, by classes. Some of these areas have 
3. Some of these have been mentioned in Table I, above, 
but are repeated to present Baum and Court’s ideas com- 
pletely. 
