2. Peculiarities of tropical climate
3. Classification of Tropics
4. Morphogenetic regions - Temperature, rainfall, humidity,
1. Tropical Environment
2. Climatic and Environmental Factors
Chap 1.Introduction toTropics
2. • Climate is a measure of the average pattern of variation in temperature,
humidity, atmospheric pressure, wind, precipitation, atmospheric particle
count and other meteorological variables in a given region over long
periods of time.
• A region's climate is generated by the climate system, which has five
components: atmosphere, hydrosphere, cryosphere, lithosphere, and
• The climate of a location is affected by its latitude, terrain, and altitude,
water bodies and their currents.
• Climates can be classified according to the average and the typical ranges of
different variables, most commonly temperature and precipitation.
4. Definition : Tropics
The tropics is the region of the Earth surrounding the Equator.
They are delimited in latitude by the Tropic of Cancer in
the Northern Hemisphere at 23°
(or 23.43661°) N and the Tropic of Capricorn in the Southern
Hemisphere at 23° (or 23.43661°) S;
these latitudes correspond to the axial tilt of the Earth.
The tropics are also referred to as the
tropical zone and the torrid zone
7. A tropical climate is a climate in the tropical region.
In the Köppen climate classification
it is a non- arid climate ‘A’
entire year temperatures of at least 18 °C (64 °F). Tropical temperature remains relatively
constant w ‘Aw’
But seasonal variations are dominated by precipitation. Change in ‘R’ every year.
Tropical Climates have almost continuous rainfall throughout the year, usually in the
Peculiarities of tropical climate
• The tropics constitute 40% of the Earth's surface area
• contain 36% of the Earth's landmass.
• the region was home to 40% of the world's population.
8. • There are normally only two seasons in tropical climates, a wet season and
a dry season.
• The Tropics is the area around the equator where prevailing trade
winds blow from east to west.
• Trade winds are caused by the Sun heating the equator more than
the North and South Poles.
• When the Sun heats land and ocean around the equator, warm,
moist air rises creating clouds, storms and rain.
• The air loses heat and moisture through rainfall.
12. 5-10 degrees from the
T = 21 °C to 30 °C)
P = 2000 mm / 100 inches
almost no drought period
Thick vegetation cover =
Upper Amazon basin of South
Northern Zaire (Congo) basin of
islands of the East Indies.
13. Tropical Wet Rainforest
•Köppen Classification - Af.
•Dominated by Maritime Tropical air masses all year long.
Temperature : The tropical wet climate is characterized by somewhat consistent daily
high temperatures ranging between 20 to 30° Celsius.
• The monthly temperature averages vary from 24 to 30° Celsius.
• Annual range of monthly temperatures is about 3° Celsius.
• It has reasonably uniform precipitation all year round, and total rainfall over 2000
millimeters or greater.
The region experiencing this climate lies within the effects of the intertropical
convergence zone all year long. Convergence and high maritime humidity
creates cumulus clouds and thunderstorms almost daily.
15. 10 degrees north and the
Tropic of Cancer.
T = 21 °C to 27 °C
P = 1800mm –
Thick three tyres of
vegetation cover = forests in
a short-drought season
occurs in the winter.
south and southeast Asia
16. Tropical Wet and Dry -Monsoon
•Köppen Classification - Aw and Am.
•Maritime Tropical air masses high Sun season and Continental Tropical air masses
low Sun season.
• This climate has distinct wet/dry periods.
• The seasonal pattern of moisture is due to the migration of the intertropical
• The wet season is synchronous with the high Sun and the presence of the
• The dry season is a result of the more stable air developing from the subsidence
associated with the presence of the subtropical high zone during the low Sun
17. • During the rainy season, the climate of this location
is similar to the tropical wet climate: warm, humid,
and has frequent thunderstorms.
During the dry season more or less semi-desert
Some regions may experience intensification of
rainfall because of monsoon development
and orographic uplift.
Tropical Wet and Dry -Monsoon
18. 10° and 20° north-
T =20 °C to 30 °C
P = 700 to 1000 mm
flat grassland vegetation.
Herbs and srcubs/ shrubs
parts of South America
N and E Australia
19. Tropical savanna
•Köppen Classification - AWh and ASh.
•Dominated by Continental Tropical air masses all year.
This climate type covers 12 percent of all land area on the continents. The heart
of the tropical desert climate is found near the tropics of Cancer and Capricorn,
usually toward the western side of the continents. Regions with this climate have
the following common climatic characteristics:
•low relative humidity and cloud cover.
•low frequency and amount of precipitation.
•high mean annual temperature.
•high monthly temperatures.
•high diurnal temperature ranges.
•high wind velocities.
27. Climatic factors - Tropics
Temperature Precipitation Chronological
• Thermal variations due to Land –Sea distribution
• Thermal variations due to Vegetation cover (Humification)
• High temperatures 18 degree cel, 21 to 30d c
• Exothermal conditions ( atm. T)
• Endothermic (Geothermal) – Chemical reactions
• Soil T.
• Latitudinal Radiated solar energy
• Air Temperature – Reaches a max during the day of between 27 & 32ºc but
occasionally it may exceed.
• The mean minimum temperature varies from 21º & 27ºc.
• Intensity and
• frequency of Rainfall – Rate of weathering
• Location of the place –Mountainous, savanna, Plains
• Forms of precipitation – Himalayas, Equatorial, deciduous
30. Chronological factors
• Climate Changes – Change in climate, vegetation with time.
-Fluvial conditions in Tertiary and
- deep weathering
• Tectonic Changes – Variation in crustal movements
and stability- gives time for weathering
Factors = T +P = 2 -weathering = 5-6 planation surfaces
(end products) – 3-4 denudation landforms -inselbergs/
32. Environmental Factors
Biotic factors Geomorphic factors Site factors Geological factors
1. Vegetation cover
2. Canopy of the forest – protects from splash erosion, sheet e.
3. Provides organic biomass - Tropics
4. Organic acids – mobilization of minerals within the soil
(exception in Savanna)
5. moisture holding, Water holding
6. Maintain channelization by plant roots.
Types – parent
35. Geomorphic factors
1. Land surface – rate of weathering
2. Age of land surface – ancient landforms – deep soil profile development
3. Effect of external factors - T, R, Solar energy, etc.
36. Site factors
1. Free drainage system
2. Zone of leaching, groundwater
3. Variation in the slope of land
37. Geological factors
1. Rock type
2. Rock structure
4. Rock cracks , faults, joints
5. Thermal expansion and contraction
6. Hydrological characteristics