Tahiti's Climate

Tahiti is a warm tropical island located in the subtropical latitudinal belt. The warm temperatures are due to Tahiti residing not far from the equator at about 17 degrees south. The diurnal (daily) temperature only varies between 78 and 85 degrees Fahrenheit throughout the year.

http://www.worldatlas.com/webimage/countrys/oceania/tahiti.htm

Above displays Tahiti's latitudinal distance from the equator.

http://www.romantic-tahiti.com/tahiti-climate.htm

Annual temperature range above shows very little variation.

 Tahiti’s seasons change with fluctuations in the trade winds. Trade winds are caused by warm air masses rising in equatorial regions. The winds are deflected to the left (Southern Hemisphere) by the earth’s rotation known as the Coriolis effect. The winds travel from subtropical high pressure zones to the intertropical convergence zone (ITCZ) located at the equator.

http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecCurrents/LecCurrents.html

This displays the creation of clouds. The trade winds move from a high pressure zone to
converge with a low pressure zone. The formation begins with stratus
clouds and ends with cumulonimbus (rain producing) clouds.

The island has two main seasons, a dry and a wet season. The dry season takes place from April to October during the Southern hemisphere’s winter. During this time, the average daily temperature is lowered due to the southeast trade winds. The rainy season is November through March which brings much of the precipitation from the Northeast humid winds.

http://www.romantic-tahiti.com/tahiti-climate.htm

The dry and wet seasons are apparent by the variation of rainfall.

http://mtp.mjmahoney.net/www/missions/pem/tahiti_pg.htm

The capital city of Papeete displaying the orographic lifting.

The topography of the island has a major influence on the spatial distribution of precipitation. Trade winds are full of moisture but do not usually produce rain unless forced to rise. Tahiti's peaks cause the air mass to rise through orographic lifting. As the air mass tries to climb over the volcanic peaks, it cools as it reaches its dew point. When the dew point is met, the clouds condense and release rain.

http://www.sci.uidaho.edu/scripter/geog100/lect/05-atmos-water-wx/05-part-7-atmos-lifting-fronts/ch5-part-7a-atmos-liftin.htm

Above shows air cooling adiabatically (by expansion) cooling of air causing precipitation. Rain falls mainly on the windward (east coast of Tahiti) before it makes it to the leeward side (west coast of Tahiti).

The majority of Tahiti’s precipitation falls on the east coast. The topography and direction of the wind causes less precipitation to make it to the west coast creating a rain shadow (shown above).  Annual rainfall on the east coast is about 138 inches compared to 59 inches on the west coast. All of these components come together to create the beautiful climate of Tahiti.




References:

Wotling, G., Bouvier, C., Danloux, J., & Fritsch, J. (2000). Regionalization of extreme precipitation distribution using the principal components of the topographical environment. Journal of Hydrology, 23(1-4), 86-101. Retrieved from http://0www.sciencedirect.com.skyline.ucdenver.edu/science/

article/pii/S0022169400002328

Carpenter, K. E. (n.d.). An introduction to the oceanography, geology, biogeography and fisheries of the tropical and subtropical western and central pacific. 1-17. Retrieved from http://www.fisheries.go.th/if-suratthani/web2/images/download/v103.pdf

Allen, C. (n.d.). Geog 1202: Introduction to physical geography. Retrieved from http://clasfaculty.ucdenver.edu/callen/1202/