Koeppens’s Scheme of Classification of Climate:
The empirical climate classification scheme was developed by Koeppen in 1918. Koeppen’s scheme is the most widely used classification of climate. Koeppen identified a close relationship between the distribution of vegetation and climate.
Koeppen selected certain values of temperature and precipitation and relate them to the distribution of vegetation and used these values for classifying the climates.
Koeppens’s Scheme of Classification of Climate/this empirical classification is based on mean annual and mean monthly temperature and precipitation data.
- Koeppen introduced the use of capital and small letters to designate climate groups and types. In this scheme, five major climatic groups were recognized in which four of which are based on temperature and one on precipitation.
- The climatic groups which have been shown by capital letters A, C, D, and E, delineate humid and B dry climates.
Climatic groups according to Koeppens’s Scheme of Classification of Climate
|A-Tropical||The average temperature of the coldest month is 18°C or higher.|
|B-Dry climates||Potential evaporation exceeds precipitation.|
|C-Warm temperature||The average temperature of the coldest month of the (mid-latitude) climates years is higher than minus 3°C but below 18°C|
|D-Cold snow forest climate||The average temperature of the coldest month is minus 3degree Celsius or below.|
|E-Cold climates||The average temperature for all months is below 10°C|
|F-Highland||Cold due to elevation.|
Classification of Groups
The climatic groups are subdivided into types, designated by small letters, based on the seasonality of precipitation and temperature characteristics.
- The seasons of dryness are indicated by small letters: f, m, w, and s, where f corresponds to no dry season.
- m-monsoon climate
- w-winter dry season
- s-summer dry season.
- The small letters a, b, c, and d refer to the degree of severity of temperature.
- The B-dry climates are subdivided using the capital letters S for steppe or semi-arid and W for deserts.
Climate type according to Koeppen
Table of Climate types according to Koeppen
|A-Tropical Humid Climate||Tropical wet||Af||No dry season|
|Tropical monsoon||Am||Monsoon, short dry season|
|Tropical wet and dry||Aw||Winter dry season|
|B-Dry Climate||Sub-tropical steppe||BSh||Low-latitude semi-arid or dry|
|Sub-tropical desert||BWh||Low-latitude arid or dry|
|Mid-latitude steppe||BSk||Mid-latitude semi-arid or dry|
|Mid-latitude desert||BWk||Mid-latitude arid or dry|
|C-Warm temperate (Mid-latitude) Climates||Humid sub-tropical||Cfa||No dry season, warm summer.|
|Mediterranean||Cs||Dry hot summer|
|Marine West Coast||Cfb||No dry season, warm and cool summer|
|D-Cold Snow-forest Climates||Humid continental||Df||NO dry season. severe winter|
|Sub-arctic||Dw||Winter is dry and very severe.|
|E-Cold Climates||Tundra||ET||No true summer|
|Polar ice cap||EF||Perennial ice|
|H-Highland||Highland||H||Highland with snow cover.|
Group A-Tropical Humid Climates
Tropical humid climates exist between the Tropic of Cancer and the Tropic of Capricorn. The presence of Inter Tropical Convergence Zone (ITCZ) and perpendicular sunrays throughout the year make the climate hot and humid.
- The annual range of temperature is very low and annual rainfall is high.
Types of Tropical Group
The tropical group is divided into three types:
- Tropical Wet Climate (Af)
- Tropical Monsoon Climate (Am)
- Tropical Wet and Dry Climate (Aw)
Tropical Wet Climate (Af):
- The Tropical wet climate is found near the equator.
- The major areas are – the Amazon basin in South America, Western equatorial Africa, and the island of East Indies.
- A significant amount of rainfall occurs every month of the year as the thundershowers in the afternoon.
- Temperature is uniformly high and the annual range of temperature is negligible.
- The maximum temperature on any day is around 30°C, whereas the minimum temperature is around 20°C.
- Tropical evergreen forests with dense canopy cover and large biodiversity are found in this area.
Examples of Af Climates:
- Apia, Samoa,
- Davao, Philippines
- Hawai, United States
- Queensland, Australia,
- Medan, Indonesia
- Ratnapura, Srilanka
- Santos, Brazil, and many more places in the world.
Tropical Monsoon Climate (Am):
This climate is found in the Indian sub-continent, the North Eastern part of South America, and Northern Australia. In these areas, heavy rainfall occurs mostly in summer, and the winter is dry.
Examples of Tropical Monsoon Climate (Am):
- Chittagong, Bangladesh
- Queensland, Australia
- Conakry, Guinea
- Guanera, Venezuela
- Jakarta, Indonesia
- Kochi, Kerala, Mangalore, Karnataka, India,
- Miami, Florida United States, and many other regions in the world.
Tropical Wet and Dry Climate (Aw):
The climate is found in the North and South of Af-type climate regions. It borders with a dry climate on the Western part of the continent and Cf or Cw on the Eastern part.
- It is extensively found in the North and South of the Amazon forest in Brazil and adjoining parts of Bolivia, and Paraguay in South America, Sudan, and South of Central Africa.
- Annual rainfall is considerably less than that in Af and Am climate types and is variable also.
- The wet season is shorter and the dry season is longer with the severe drought.
- Temperature is high throughout the year with the greatest diurnal range in the dry season.
- In this climate, deciduous forests and tree-shredded grasslands occur.
Examples of AW climate:
- Abuza, Nigeria
- Bangkok, Thailand
- Bangui, Central African Republic
- Brasilia, Brazil
- Caracas, Venezuela
- Chennai, Tamil Nadu, India, and many other regions of the world.
Group B-Dry Climates
Dry climates are characterized by very low rainfall which is not adequate for the growth of plants. These climates cover a very large area extending over large latitudes from 15 °-60° North and South of the equator.
At low latitudes, from 15° – 30°, they occur in the area of subtropical high where subsidence and inversion of temperature do not produce rainfall.
- On the western margin of the continents, adjoining the cold current, particularly over the West Coast of South America, they extend more equatorward and occur on the coastland.
- In middle latitudes, from 35°-60° North and South of the equator, they are confined to the interior of continents where Maritime humid winds do not reach and to areas often surrounded by mountains.
- Dry climates are divided into steppe or semi-arid climates (BS) and desert climates (BW). They are further sub-divided as sub-tropical steppe (Bsh) and sub-tropical desert (BWh) at latitudes from 15 °to 35° and mid-latitude steppe (BSk), and mid-latitude desert (BWk) at latitudes between 35° to 60°.
Sub-tropical Steppe (BSh) and Sub-tropical Desert (BWh) Climates:
Both of these have common precipitation and temperature characteristics. Sub-tropical steppe receives slightly high rainfall than the desert which is adequate enough for the growth of sparse grassland. It is located in the transition zone between humid and dry climates.
- In both climates the rainfall variable.
- The variability of rainfall affects life in the steppe much more than in the desert, more often causing famine.
- Rain occurs in short intense thundershowers in deserts and is ineffective in building soil moisture.
- Fog is common in the coastal deserts bordering cold currents.
- The maximum temperature in the summer is very high.
- The highest shade temperature of 58°C was recorded at Al Aziziyah, Libya on 13th September 1922. The annual and diurnal range of temperature was also high.
Group C-Warm Temperature (Mid-Latitude) Climates
It extends from 30°-50° of latitude mainly on the Eastern and western margins of continents. Generally, warm summers with mild winters are found in these climates.
The group C-warm temperature climates are divided into four types:
Humid Sub-tropical Climate (Cwa):
- This climate is dry in winter and hot in summer.
- It occurs poleward towards the tropic of Cancer and Capricorn, mainly in North Indian plains and South China interior plains.
- The climate is similar to the Aw climate except that the temperature in winter is warm.
Mediterranean Climate (Cs):
This type of climate occurs around the Mediterranean Sea, along the west coast of continents in sub-tropical latitudes between 3° to 40° latitudes.
For example Central California, Central Chile, along the coast in South–Eastern and South Western Australia.
- These areas come under the influence of subtropical highs in summer and westerly wind in winter.
- The climate is characterized by hot, dry summer and mild, rainy winter.
- The monthly average temperature in summer is around 25 °C and in winter below 10°C.
- The annual precipitation of this climate group ranges between 35-90 cm.
Humid Sub-tropical climate (Cfa):
This climate has no dry season and mild winter. The humid sub-tropical climate is found in the Eastern part of the continent in sub-tropical latitudes. The air masses are generally unstable and cause rainfall throughout the year in this region.
- This climate is found in the eastern USA, Southern and Eastern China, Southern Japan, North-eastern Argentina, Coastal South Africa, and the Eastern Coast of Australia.
- The annual average of precipitation varies from 75-150 cm.
- Thunderstorms in summer and frontal precipitation in winter are common.
- The mean monthly temperature in summer is around 27°C and in winter it varies from 5°C to 12 °C with a small daily range of temperature.
Marine West Coast Climate (Cfb):
The Marine West Coast Climate is located poleward from the Mediterranean climate on the west coast of the continents. The main areas of this climate are North Western Europe, the West Coast of North America, the North of California, Southern Chile, South-Eastern Australia, and New Zealand.
- In summer the mean temperature ranges from 15°C – 20°C and in winter 4°C to 10°C.
- The annual and daily ranges of temperature are small.
- In this region, precipitation occurs throughout the year which varies greatly from 50-250 cm.
Group D-Cold Snow Forest Climate
This climate occurs in the large continental area in the Northern Hemisphere between 40° – 70° North Latitude in Europe, Asia, and North America. The severity of winter is more pronounced in higher latitudes.
Group D-climate is divided into two types:
Cold Climate with Humid Winters (Df):
- It occurs poleward of the marine west coast climate and mid-latitude steppe.
- The winters are cold and snowy and the frost-free season is short.
- The annual ranges of temperature are large.
- Weather changes are abrupt and short.
- The winters are more severe in poleward.
Cold Climate with Dry Winters (Dw):
- This type of climate mainly occurs over North-Eastern Asia.
- Anti-cyclonic conditions develop in winter, its weakening in summer set sets in a monsoon-like reversal of wind in this region.
- Poleward summer temperature is lower while winter temperature is extremely low.
- In this climate region, the temperature goes below freezing point at many locations for up to seven months in a year.
- A low annual amount of precipitation of 12-15 cm occurs only in summer.
Group E- Polar Cliamate
The Polar climate exists poleward beyond 70° latitude. There are two types of group E-Polar climate:
Tundra Climate (ET):
- Tundra Cliate is named after the type of vegetation, like low-growing mosses, lichens, and flowering plants.
- This is the region of permafrost where the subsoil is permanently frozen.
- The short growing season and water logging support only low-growing plants.
- The tundra regions have a very long duration of daylight during Summer.
Ice Cap Climate (EF):
- It occurs over interior Greenland and Antarctica.
- The temperature in this region is found below freezing point even in summer.
- This area receives a very low amount of precipitation.
- The snow and ice get accumulated and the mounting pressure causes the deformation of ice sheets.
- They break and move the icebergs that float in the Arctic and Antarctic waters.
- The plateau Station Antarctica, 79°S, portrays this climate.
Group H-Highland Climates:
The climates under group “H” are governed by topography.
- Large changes in mean temperature occur over short distances in high mountains.
- Types of precipitation and intensity also vary across highlands.
- There is vertical zonation of layering of climatic types with elevation in the mountain environment.
Significances of Koeppens’s Scheme of Classification of Climate:
Koeppens’s Scheme of Classification of Climate is based on the empirical relationship between climate and vegetation.
- Koeppens classification provides an efficient way to describe climatic conditions defined by temperature and precipitation and their seasonality with a single metric.
- The climatic classification of Koeppen is ecologically relevant so it has been widely used to map the geographic distribution of long-term climate and associated ecosystem conditions.
Reference: Koeppens’s Scheme of Classification of Climate
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