World Climatic Patterns

World climatic patterns are classified as hot-wet equatorial climates, savanna climates, tropical monsoon climates, desert climates, steppe climates, Mediterranean climates, Warm Temperate Eastern Margin Climates, British type climates, taiga climates, Laurentian climates, and polar climates.

Tropical Humid Climates

Tropical humid climates exist between Tropic of Cancer and Tropic ofCapricorn.
The sun being overhead throughout the year and the presence of Inter Tropical Convergence Zone (INTCZ) make the climate hot and humid.
Annual range of temperature is very low and annual rainfall is high.
The tropical group is divided into three types, namely
Af – Tropical wet climate;
Am – Tropical monsoon climate;
Aw – Tropical wet and dry climate.

Tropical Wet Climate

Also known as ‘The Hot, Wet Equatorial Climate’, ‘Equatorial Rainforest Climate’.
The regions are generally referred as ‘Equatorial Rainforests’, ‘Equatorial Evergreen Forests’, ‘Tropical Moist Broadleaf Forest’, ‘Lowland Equatorial Evergreen Rainforest’.

Distribution

Mostly between 5° N and S of Equator. Its greatest extent is found in the lowlands of the Amazon, the Congo, Malaysia and the East Indies
Equatorial Climate
- Dominated by Maritime Tropical air masses.
Temperature
- Temperature is uniform throughout the year.
- The mean monthly temperatures are always around 27° C with very little variation.
There is no winter
- Cloudiness and heavy precipitation moderate the daily temperature.
- Regular land and sea breezes assist in maintaining a truly equable climate.
- The diurnal range of temperature is small, and so is the annual range.
Precipitation
- Precipitation is heavy and well distributed throughout the year.
- Annual average is always above 150 cm.
- In some regions the annual average may be as high as 250 – 300 cm.
- There is no month without rain (distinct dry season is absent).
- The monthly average is above 6 cm most of the times.

Equatorial Vegetation

High temperature and abundant rainfall support a luxuriant tropical rain forest.
In the Amazon lowlands, the forest is so dense that it is called ‘selvas’.
Unlike the temperate regions, the growing season here is all the year round-seeding, flowering, fruiting and decaying do not take place in a seasonal pattern.
The equatorial vegetation comprises a multitude of evergreen trees that yield tropical hardwood, e.g. mahogany, ebony, dyewoods etc.
In the coastal areas and brackish swamps, mangrove forests thrive.

Canopy

From the air, the tropical rain forest appears like a thick canopy of foliage, broken only where it is crossed by large rivers or cleared for cultivation.
All plants struggle upwards (most ephiphytes) for sunlight resulting in a peculiar layer arrangement.

Epiphyte

An epiphyte is a plant that grows harmlessly upon another plant (such as a tree) and derives its moisture and nutrients from the air, rain, and sometimes from debris accumulating around it.