Climate change, Pacific climate drivers and observed precipitation variability in Tahiti, French Polynesia
Hopuare, Marania ; Pontaud, Marc ; Céron, Jean-Pierre ; Ortéga, P. ; Laurent, Victoire
This study addresses the low-frequency variability of precipitation and the detection of climate change over Tahiti, a small orographic island in French Polynesia in the tropical South Pacific. The analysis of new homogenized rainfall amounts over the period 1961-2011 shows no significant trend related to climate change, but highlights the interactions between ENSO, the South Pacific Convergence Zone (SPCZ) and rainfall during the latest positive phase of the Interdecadal Pacific Oscillation (IPO) (1977-1999). During this particular phase, the SPCZ is closer to Tahiti and induces positive large-scale precipitation. On interannual time scales, more frequent and strong El Niño events favour a northward SPCZ migration. This northern position causes a surface flux over Tahiti Island, which forces orographic precipitation on the windward side. During the negative phase of IPO, no clear link is established between SPCZ, ENSO and rainfall variability.
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