Types of Climate
He divided climate in 5 different types :-
1. A-Type (Humid Tropical climate)
Good Rainfall, winter-less region, warm and moist conditions all year with Annual mean temperature is always more than 18 degree Celsius.
2. B-Type (Dry climate)
Where Annual precipitation is less than evaporation and constant water deficit
3. C-Type (Humid Meso-thermal /Mid-latitude Warm Temperate Climate)
Mild winters with temperature of coldest and warmest month is 8 degree Celsius to 18 degree Celsius and below 18 degree Celsius respectively.
4. D-Type (Humid Mico-thermal/Cold forest Climate)
Severe winters, Mean temperature of coldest and warmest month is 3 degree Celsius and 13 degree Celsius respectively.
5. E-Type (Polar Climate)
Summer-less region with average temperature of the warmest month remains below 10 degree Celsius.
Koeppen further subdivided these 5 climates in different subtypes on the basis of these parameters :-
- f - All year rain, Rainfall of driest month is more than 6 cm and temperature of coldest month is above 18 degree Celsius.
- m- Monsoon type climate, short dry season, average precipitation in driest month less than 6 cm.
- W - Winter dry Region.
- S- summer dry Region.
Based on above he divided climate 5 Climate into 11 parts:-
1. Tropical Humid Climate (A type Climate)
Characterized by winter-less region, Annual mean temperature more than 18 degree Celsius, sufficient (sometimes excess) moisture in air.
It is classified into 4 subtypes : -
I. Af Climate - Rainfall throughout year with the precipitation in driest month is more than 6 cm. High mean temperature with very low daily range of temperature throughout the year. This region symbolizes Equatorial zone.
II. Am Climate - characterized by short dry season. Adequate rainfall which maintain Groundwater Table and hence soil is wet throughout year. Which led to dense forest in the region. It symbolizes Tropical Monsoon Climate.
III. Aw Climate - Tropical Humid Dry Climate winter Dry region. This is characterized by rainfall in summer season. High temperature throughout the year. Precipitation of at least one month is less than 6 cm. It symbolizes Savanna type of climate.
The boundary between Am and Am climate is separated on the basis of a formulae given by Koeppen. i.e.
a = 3.94-r/25
a - Rainfall of driest month
r- Annual mean Rainfall (in inches)
If Actual rainfall of driest month of a particular place is less than 'a' than it is called as 'Aw' Climate.
And when Actual rainfall of driest month of place is more than the value of 'a' than it is termed as 'Am' climate.
IV. As Climate - Tropical Summer Dry Climate. This type of climate is very rare.
2. Dry Climate (B Climate)
Characterized by low precipitation and High evaporation. Precipitation is not enough to maintain Ground Water Table. Hence less vegetation or thorny vegetation is found.
It is also divided into two types i.e.
I. BW Climate - Dry Steppe type climate characterized by dry winters
II. Bs Climate - Desert climate, characterized by very low rainfall and dry summers.
BW and Bs is differentiated on following formula:-
r = (0.44t-8.5)/2
r - Mean Annual Rainfall
t - Mean Annual Temperature
If Mean Annual Rainfall is more than the value of r. than it is called as 'BS' Climate.
If Mean Annual Rainfall is less than the value of r than it is called as 'BW' Climate
Koeppen further subdivided this climate into 4 types:-
I. BWh(Tropical Desert Climate)
II. BWk(Tropical Steppe Climate)
III. BSh(Mid-Lattitude Cold Desert Climate).
IV. BSk(Mid-Lattitude Cold Steppe Climate)
where,
h- Mean Annual temperature more than 18 degree Celsius
k - Mean Annual temperature is less than 18 degree Celsius
a - Summer dry, 3 times more rainfall in winter than (wettest month) than the driest summer month.
w - Winter dry , 10 times more rainfall in wettest summer month than driest winter month.
3. C type Climate( Humid Meso-thermal)
Also called as Mid-Lattitude Warm Temperate climate.
Mild winters with temperature ranging between 8 degree Celsius to 18 degree Celsius in coldest and warmest month respectively
It is further subdivided into three types.
I. Cf type of Climate - It represents Western Europe type of Climate where Rainfall through out the year with precipitation more than 1.2 inches in the driest month of summer season.
It is further subdivided into two types:-
I. Cfa- Humid Subtropical
II. CFB - Marine West Coast type
II. CW Climate - It represents China type climate having dry winters with 10 times more rainfall in wettest summer month than the rainfall in driest month than the Rainfall in Dries winter month and Long dry winters.
III. Ca Climate - It represents Mediterranean type of climate characterized by long dry summer.
3 times more Rainfall in the wettest winter month than driest summer month. Precipitation in the driest summer season is less than 1.2 inches.
4. D type Climate - Humid Mico- thermal/Cold Forest type climate.
Characterized by severe cold with Mean temperature in winter is below minus 3 degree Celsius while this is in summer above 10 degree Celsius . Ground surface covered with snow for several months of year.
It is divided into two types:-
I. Df type - Rain throughout the year. It is further divided in three types
(a) Dfa(Long Warm Summer-Continental) (b) Dfb(Long and Cool Summer) (c) Dfc(Short cool Summer-Subarctic)
II. Dw type Humid Cold Climate with Dry winters.
(a) Dwa(Continental Climate with long cool summer) (b) Dwb(Cool Short Summer) (c) Dwc(Cold Winters)
where,
a- Warm summer season, warmest month = above 22 degree Celsius
b- Cold winter season, warmest month - below 22 degree Celsius
c - Cold short summer cold season
5. E type - Polar Climate
Very cold region with mean temperature in winter is -3degree Celsius while it is in warmest summer months less than 10 degree Celsius but above 0 degree Celsius.
It is divided into two types: -
I. Et - Tundra Climate- Characterized by having the Tundra vegetation, warmest month temperature is 0 to 10 degree Celsius.
II. Ef - Snow capped Area- All month below 0 degree Celsius and permanently snow capped.
Merits of Koeppen Classification
- Very simple, generalised, easy to comprehend.
- Relates vegetation with climate.
- Uses two easily measurable environmental factors i.e. temperature and rainfall.
- It is widely acclaimed for its simplicity.
Demerits
- Over emphasis on Annual mean temperature and Rainfall.
- Over generalised classification Avoided some important climatic indicators like, Rainfall intensity, cloudiness, Daily temperature extremes etc.
- Highly raw in character hence require a lot of remembering and memory power.
- Negated the causative factors of climate differentiation.