Tropical savanna climate

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Worldwide zones of Tropical savanna climate (Aw/As). Koppen-Geiger Map Aw present.svg
Worldwide zones of Tropical savanna climate (Aw/As).

Tropical savanna climate or tropical wet and dry climate is a type of climate that corresponds to the Köppen climate classification categories Aw (for a dry winter) and As (for a dry summer). The driest month has less than 60 mm (2.4 in) of precipitation and also less than of precipitation. [1] :200–1

Contents

This latter fact is in direct contrast to a tropical monsoon climate, whose driest month sees less than 60 mm (2.4 in) of precipitation but has more than of precipitation. In essence, a tropical savanna climate tends to either see less rainfall than a tropical monsoon climate or have more pronounced dry season(s).

In tropical savanna climates, the dry season can become severe, and often drought conditions prevail during the course of the year. Tropical savanna climates often feature tree-studded grasslands, rather than thick jungle. It is this widespread occurrence of tall, coarse grass (called savanna) which has led to Aw and As climates often being referred to as tropical savanna. However, there is some doubt whether tropical grasslands are climatically induced. Additionally, pure savannas, without trees, are the exception rather than the rule.

Versions

There are generally four types of tropical savanna climates:

Distribution

Tropical savanna climates are most commonly found in Africa, Asia and South America. The climate is also prevalent in sections of Central America, northern Australia, the Pacific Islands, in sections of North America and some islands in the Caribbean. Most places that have this climate are found at the outer margins of the tropical zone, but occasionally an inner-tropical location (e.g., San Marcos, Antioquia, Colombia) also qualifies. Similarly, the Caribbean coast, eastward from the Gulf of Urabá on the ColombiaPanamá border to the Orinoco river delta, on the Atlantic Ocean (ca. 4,000 km (2,485 mi)), have long dry periods (the extreme is the BSh climate (see below), characterized by very low, unreliable precipitation, present, for instance, in extensive areas in the Guajira, and Coro, western Venezuela, the northernmost peninsulas in South America, which receive <300 mm (11.8 in) total annual precipitation, practically all in two or three months). This condition extends to the Lesser Antilles and Greater Antilles forming the Circumcaribbean dry belt. The length and severity of the dry season diminishes inland (southward); at the latitude of the Amazon river—which flows eastward, just south of the equatorial line—the climate is Af. East from the Andes, between the arid Caribbean and the ever-wet Amazon, are the Orinoco river Llanos or savannas, from where this climate takes its name.

Sometimes As is used in place of Aw if the dry season occurs during the time of higher sun and longer days, such as in Honolulu, Hawaii. [2] This may also be due to a rain shadow effect that cuts off summer precipitation in a tropical area. This is the case in East Africa (Mombasa, Kenya, Somalia), Sri Lanka (Trincomalee) and coastal regions of Northeastern Brazil (from Fortaleza through Natal to Maceió), for instance. The difference between 'summer' and 'winter' in such locations is usually so slight that a distinction between an As and Aw climate is a quibble. In most places that have tropical wet and dry climates, however, the dry season occurs during the time of lower sun and shorter days because of reduction of or lack of convection, which in turn is due to the meridional shifts of the Intertropical Convergence Zone during the entire course of the year.

Cities with a tropical savanna climate

Some examples of tropical savanna climates

Banjul, The Gambia
Climate chart (explanation)
J
F
M
A
M
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0.5
 
 
32
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32
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1.6
 
 
33
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0.7
 
 
32
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: BBC Weather [3]
Monte Cristi, Dominican Republic
Climate chart (explanation)
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74
 
 
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68
 
 
33
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108
 
 
31
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84
 
 
29
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: NOAA [4]
Brasília, Brazil
Climate chart (explanation)
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241
 
 
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26
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: World Weather Information Service
Darwin, Australia
Climate chart (explanation)
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466
 
 
32
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108
 
 
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25
 
 
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2.3
 
 
31
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1.2
 
 
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5.8
 
 
32
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18
 
 
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65
 
 
34
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137
 
 
34
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276
 
 
33
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: Australian Bureau of Meteorology
Bangkok, Thailand
Climate chart (explanation)
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13
 
 
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35
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157
 
 
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175
 
 
33
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219
 
 
33
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334
 
 
33
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292
 
 
33
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50
 
 
32
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6.3
 
 
32
22
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: Thai Meteorological Department [5]
Tegucigalpa, Honduras
Climate chart (explanation)
J
F
M
A
M
J
J
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5.3
 
 
26
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4.7
 
 
27
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9.9
 
 
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43
 
 
30
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144
 
 
30
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29
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82
 
 
28
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29
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177
 
 
29
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109
 
 
27
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40
 
 
26
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9.9
 
 
25
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Average max. and min. temperatures in °C
Precipitation totals in mm
Source: WMO [6]

See also

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Miskito pine forests

The Miskito pine forests ecoregion covers lowland pine forests and savanna along much of the Mosquito Coast in northeastern Nicaragua and southeastern Honduras. Pines are adapted to grow in the poor soil, relative to the surrounding moist forest, and repeated burning have left one species – the Caribbean pine – dominant. Although the ecoregion receives high levels of rain, the hard soils, repeated burning, and exposure to hurricanes have left expanses of 'pine savanna' and seasonal wetlands. The area is thinly settled by humans and there is little crop agriculture.

Coastal Venezuelan mangroves

The Coastal Venezuelan mangroves ecoregion covers the salt-water mangrove forests along the Caribbean Sea and Atlantic Ocean coast of Venezuela, from Cocinetas Basin to the edge of the Caño Manamo River and the Orinoco Delta in the east. It is one of the largest mangrove ecoregions in South America, with an area of 5,698 km2, and stretching across over 400 km of Venezuelan coastline.

Trinidad and Tobago moist forests

The Trinidad and Tobago moist forests ecoregion covers most of Trinidad Island and Tobago Island near the coast of South America where the southeastern Caribbean Sea meets the Atlantic Ocean. Small portions of the islands around river estuaries and coastal lowlands are mangroves or dry forests. Species diversity is very high, in particular for plants and birds. Tobago, being much smaller, has fewer species.

References

  1. McKnight, Tom L; Hess, Darrel (2000). "Climate Zones and Types" . Physical Geography: A Landscape Appreciation . Upper Saddle River, New Jersey: Prentice Hall. ISBN   978-0-13-020263-5.
  2. "Honolulu, Hawaii Köppen Climate Classification". Weatherbase.
  3. "World Weather Information Service — Banjul" . Retrieved 3 March 2020.
  4. "Station Name: MONTE CRISTI ... Country: DOMINICAN REPUBLIC". NOAA .
  5. "Climatological Data for The Period 1981–2010". Thai Meteorological Department. p. 16.
  6. "Weather Information for Tegucigalpa, Country: HONDURAS". WMO .