Koppen Classification of Climate:
For decades, a climate classification devised by WladimirKöppen (1846–1940) has been the best-known and most used tool for presenting the world pattern of climates.
For decades, a climate classification devised by WladimirKöppen (1846–1940) has been the best-known and most used tool for presenting the world pattern of climates.
The
Köppen classificationuses easily obtained data: mean monthly and annual values
of temperature and precipitation.
Furthermore,
the criteria are unambiguous, simple to apply, and divide the world into
climate regions in a realistic way.
Köppen
believed that the distribution of natural vegetation was the best expression of
an overall climate.
Consequently,
the boundaries he chose were largely based on the limits of certain plant
associations.
For
decades, a climate classification devised by WladimirKöppen (1846–1940) has
been the best-known and most used tool for presenting the world pattern of
climates.
The
Köppen classificationuses easily obtained data: mean monthly and annual values
of temperature and precipitation.
Furthermore,
the criteria are unambiguous, simple to apply, and divide the world into
climate regions in a realistic way.
Köppen
believed that the distribution of natural vegetation was the best expression of
an overall climate.
Consequently,
the boundaries he chose were largely based on the limits of certain plant
associations.
Köppen’s Classification Scheme:
Köppen
recognized five principal climate groups, each designated with a capital letter:
A(humid
tropical),
B(dry),
C(humid
middle-latitude, mild winters),
D(humid
middle-latitude, severe winters),and
E(polar).
Four
groups (A, C, D, E) are defined by temperature.
The
fifth, the B group, has precipitation as its primary criterion.
Climate Controls:
Order
exists in the distribution of climate elements and the pattern of climates is
not by chance.
The
world's climate pattern reflects a regularand dependable operation of the major
climate controls.
Climate Controls (cont.)
The major
controls of climate are::
(1)
latitude(variations in the receipt of solar energy and temperature differences
are largely a function of latitude),
(2)
land/water influence(marine climatesare generally mild, while continental
climatesare typically much more extreme),
(3)
geographic position and prevailing winds(the moderating effect of water is more
pronounced along the windward side of a continent),
(4)
mountains and highlands(mountain barriers prevent maritime air masses from
reaching far inland, trigger orographic rainfall, and where they are extensive,
create their own climatic regions),
(5) ocean
currents(poleward-moving currents cause air temperatures to be warmer than
would be expected), and
(6)
pressure and wind systems(the world distribution of precipitation is closely
related to the distribution of Earth's major pressure and wind systems).
Type A Climate:
Situated
along the equator, the wet tropics(Af, Am) constant high temperatures and
year-round rainfall combine to produce the most luxuriant vegetation in
climatic realm—the tropical rain forest.
Temperatures
in these regions usually average 25°C (77°F) or more each month and the daily
temperature variations characteristically greatly exceed seasonal differences.
Precipitation
in Afand Am climates is normally from 175 to 250 centimeters (68 to 98 inches)
per year and is more variable thantemperature, both seasonally and from place
to place.
Thermally
induced convection coupled with convergence along the intertropicalconvergence
zone(ITCZ)leads to widespread ascent of the warm, humid, unstable air and ideal
conditions for precipitation.
Type B Climate:
Dry
regions of the world cover about 30 percent of Earth's land area.
Other
than their meager yearly rainfall, the most characteristic feature of dry
climates is that precipitation is very unreliable.
Climatologists
define a “dry climate”as one in which the yearly precipitation is less than the
potential water loss by evaporation.
To define
the boundary between dry and humid climates, the Köppen classification uses
formulas that involve three variables:
(1)
average annual precipitation,
(2)
average annual temperature, and
(3)
seasonal distribution of precipitation.
Type C Climate:
Humid
middle-latitude climateswith mild winters (C climates) occur where the average
temperature of the coldest month is less than 18°C (64°F) but above -3°C
(27°F).
Several C
climate subgroups exist.
Type D Climate:
Humid
continental climates with severe winters(D climates) experience severe winters.
The
average temperature of the coldest month is -3°C (27°F) or below and the
average temperature of the warmest month exceeds 10°C (50°F).
The
greatest annual temperature ranges on Earth occur here.
Type E Climate:
Polar
climates(ET, EF) are those in which the mean temperature of the warmest month
is below 10°C (50°F).
Annual
temperature ranges are extreme, with the lowest annual means on the planet.
Although
polar climates are classified as humid, precipitation is generally meager, with
many nonmarine stations receiving less than 25 centimeters (10 inches)
annually.
Polar Climates:
Two types
of polar climates are recognized.
Found
almost exclusively in North America, the tundra climate(ET), marked by the 10°C
(50°F) summer isotherm at its equatorward limit, is a treeless region of
grasses, sedges, mosses, and lichens with permanently frozen subsoil, called
permafrost.
The ice
cap climate(EF) does not have a single monthly mean above 0°C. Consequently,
the growth of vegetation is prohibited, and the landscape is one of permanent
ice and snow.
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