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" and "As". Tropical savanna climates have monthly mean temperatures above 18 °C (64 °F) in every month of the year and typically a pronounced dry season, with the driest month having less than 60 mm (2.36 inches) of precipitation and also less than 100 – [total annual precipitation mm/25] of precipitation. [1]:200–1
This latter fact is in direct contrast to a tropical monsoon climate, whose driest month sees less than 60 mm of precipitation but has more than 100 – [total annual precipitation mm/25] 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, course grass (called savanna) which has lead 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.
Contents
1Versions
2Distribution
3Some examples of tropical savanna climates
4See also
5References
Versions
There are generally four types of tropical savanna climates:
Distinct wet and dry seasons of relatively equal duration. Most of the region's annual rainfall is experienced during the wet season and very little precipitation falls during the dry season.
A lengthy dry season and a relatively short wet season. This version features seven or more dry season months and five or fewer wet season months. There are variations within this version:
On one extreme, the region receives just enough precipitation during the short wet season to preclude it from a semi-arid climate classification. This drier variation of the tropical savanna climate is typically found adjacent to regions with semi-arid climates.
On the other extreme, the climate features a lengthy dry season followed by a short but extremely rainy wet season. However, regions with this variation of the climate do not experience enough rainfall during the wet season to qualify as a tropical monsoon climate.
A lengthy wet season and a relatively short dry season. This version features seven or more wet season months and five or fewer dry season months. This version's precipitation pattern is similar to precipitation patterns observed in some tropical monsoon climates, but does not experience enough rainfall during the wet season to be classified as such.
A dry season with a noticeable amount of rainfall followed by a rainy wet season. In essence, this version mimics the precipitation patterns more commonly found in a tropical monsoon climate, but do not receive enough precipitation during either the dry season or the year to be classified as such.
Distribution
Tropical savanna climates are most commonly found in Africa, Asia and northern South America. The climate is also prevalent in sections of Central America, northern Australia, the Pacific Islands, in sections of Mexico 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 Colombia – Panamá border to the Orinoco river delta, on the Atlantic Ocean (ca. 4,000 km), have long dry periods (the extreme is the BSh climate (see below), characterised 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 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 often due to a rain shadow effect that cuts off summer precipitation in a tropical area. This is the case in parts of Hawaii, 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 course of the year.
Some examples of tropical savanna climates
Accra, Ghana
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
15
31
23
33
31
24
56
31
24
81
31
24
142
31
24
178
29
23
46
27
23
15
27
22
36
27
23
64
29
23
36
31
24
23
31
24
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: BBC Weather[2]
Imperial conversion
J
F
M
A
M
J
J
A
S
O
N
D
0.6
87
73
1.3
88
75
2.2
88
76
3.2
88
76
5.6
87
75
7
84
74
1.8
81
74
0.6
80
71
1.4
81
73
2.5
85
74
1.4
87
75
0.9
88
75
Average max. and min. temperatures in °F
Precipitation totals in inches
Monte Cristi, Dominican Republic
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
74
29
19
47
29
20
48
30
20
59
31
21
60
32
22
40
33
23
22
34
23
28
34
23
35
34
23
68
33
22
108
31
21
84
29
20
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: NOAA[3]
Imperial conversion
J
F
M
A
M
J
J
A
S
O
N
D
2.9
84
67
1.9
85
67
1.9
86
68
2.3
87
70
2.4
89
72
1.6
92
73
0.8
92
74
1.1
93
74
1.4
93
73
2.7
91
72
4.3
87
70
3.3
85
68
Average max. and min. temperatures in °F
Precipitation totals in inches
Brasília, Brazil
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
241
27
17
215
27
17
189
27
18
124
27
17
39
26
15
8.8
25
13
12
25
13
13
27
15
52
28
16
172
28
17
238
27
18
249
26
18
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: World Weather Information Service [1]
Imperial conversion
J
F
M
A
M
J
J
A
S
O
N
D
9.5
80
63
8.5
80
63
7.4
81
64
4.9
80
62
1.5
78
59
0.3
77
56
0.5
77
55
0.5
81
58
2
83
61
6.8
82
63
9.4
80
64
9.8
79
64
Average max. and min. temperatures in °F
Precipitation totals in inches
Darwin, Australia
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
424
32
25
371
31
25
315
32
25
100
33
24
22
32
22
1.8
31
20
1.1
31
19
4.8
31
20
16
33
23
70
33
25
142
33
25
252
33
25
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: Australian Bureau of Meteorology [2]
Imperial conversion
J
F
M
A
M
J
J
A
S
O
N
D
17
89
77
15
89
76
12
89
76
4
91
75
0.9
90
72
0.1
87
68
0
87
67
0.2
89
69
0.6
91
73
2.8
92
77
5.6
92
78
9.9
91
78
Average max. and min. temperatures in °F
Precipitation totals in inches
Mandalay, Myanmar
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
4
29
13
2
32
15
1
36
20
40
38
24
138
37
26
116
34
26
83
34
26
136
32
25
150
33
25
125
32
24
38
30
19
6
28
15
Average max. and min. temperatures in °C
Precipitation totals in mm
Imperial conversion
J
F
M
A
M
J
J
A
S
O
N
D
0.2
83
56
0.1
90
59
0
96
67
1.6
101
76
5.4
98
78
4.6
94
78
3.3
94
78
5.4
90
77
5.9
92
77
4.9
90
74
1.5
86
67
0.2
83
59
Average max. and min. temperatures in °F
Precipitation totals in inches
See also
Tropics
Köppen climate classification
Tropical marine climate
References
^McKnight, Tom L; Hess, Darrel (2000). "Climate Zones and Types". Physical Geography: A Landscape Appreciation. Upper Saddle River, New Jersey: Prentice Hall. ISBN 0-13-020263-0..mw-parser-output cite.citationfont-style:inherit.mw-parser-output qquotes:"""""""'""'".mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-lock-free abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-subscription abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em
^"Average Conditions Accra, Ghana". BBC Weather. May 2011. Archived from the original on 21 October 2006. Retrieved 9 September 2009.
^"Station Name: MONTE CRISTI ... Country: DOMINICAN REPUBLIC". NOAA.
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