within this range on which we could expect the normal
or mean temperature to occur. This study could be
broken down further into hours of the day, etc., as
Q6-6. If one adds all the daily high temperatures for
determined by this calculation?
A temperature of 124 degrees Fahrenheit was
the highest temperature ever recorded at a
climatological parameter was determined?
What is a degree-day?
CLASSIFICATION OF CLIMATE
climatic zones and climatic types as they relate
to the classification of climate.
The climate of a given region or locality is
determined by a combination of several meteorological
elements and not by just one element. For example, two
regions may have similar temperature climates but very
difference, therefore, becomes apparent only if more
than one climatic factor is considered.
Since the climate of a region is composed of all of
the various climatic elements, such as dew, ice, rain,
temperature, wind force, and wind direction, it is
obvious that no two locations can have exactly the same
climate. However, it is possible to group similar areas
into what is known as a climatic zone.
The basic grouping of areas into climatic zones
consists of classifying climates into five broad belts
Actually they are zones of sunshine or solar climate and
include the torrid or tropical zone, the two temperate
zones, and the two polar zones. The tropical zone is
limited on the north by the Tropic of Cancer and on the
south by the Tropic of Capricorn, which are located at
23 1/2° north and south latitude, respectively. The
Temperate Zone of the Northern Hemisphere is limited
on the south by the Tropic of Cancer and on the north by
the Arctic Circle located at 66 1/2° north latitude. The
Temperate Zone of the Southern Hemisphere is
bounded on the north by the Tropic of Capricorn and on
the south by the Antarctic Circle located at 66 1/2°
south latitude. The two polar zones are the areas in the
Polar Regions which have the Arctic and Antarctic
Circles as their boundaries.
isotherms rather than by parallels of latitude (fig. 6-1).
A glance at any chart depicting the isotherms over the
surface of the earth shows that the isotherms do not
coincide with latitude lines. In fact, at some places the
isotherms parallel the longitude lines more closely than
they parallel the latitude lines. The astronomical or
light zones therefore differ from the zones of heat.
Any classification of climate depends to a large
extent on the purpose of the classification. For instance,
a classification for the purpose of establishing air
important would differ considerably from one for
establishing the limits of areas that are favorable for the
growing of crops. There are three classifications that
merit particular attention. They are the classifications
of C. W. Thornthwaite, W. Köppen, and G. T.
Thornthwaites classification of climates places a
great deal of emphasis on the effectiveness of
precipitation. Effectiveness of precipitation refers to
the relationship between precipitation and evaporation
at a certain locality. Thornthwaite classified climates
into eight main climatic groups; five groups give
primary emphasis to precipitation and the other three
groups are based on temperature.
Köppens classification includes five main climatic
types. They are tropical rain, dry, warm temperate
rainy, cool snow forest (boreal), and polar climates.
These main types are further divided into climatic
provinces. The Köppen classification is based mainly
on temperature, precipitation amount, and season of
maximum precipitation. Numerical values for these
elements constitute the boundaries of the above types,
which were selected primarily according to their effect
on plant growth. Figure 6-2, shows Köppens climatic