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1. Introduction
Tropical cyclones (TCs) are among the most deadly and destructive natural disasters on Earth. Despite their high societal impact and the numerous investigations on TCs, their dynamics and their interaction with the upper ocean still present a large number of fascinating and unresolved issues (e.g., Emanuel 2003; Wang 2012).
French Polynesia is not generally regarded as a cyclone-prone area, despite the warm surrounding ocean, because of the relatively strong wind shear over the troposphere, which provides an unfavorable environment to TC genesis. The western South Pacific area is comparably more favorable to TCs. The ENSO (El Niño Southern Oscillation,) however, modifies this picture. In the central and eastern South Pacific Ocean, the hurricane season is typically more active during El Niño both because of an increase of the SST (Basher and Zheng 1995) and the expanded area of low vertical wind shear (Dowdy et al. 2012).
A moderate El Niño episode occurred between June 2009 and May 2010. Tropical phenomena thus developed farther to the east in the South Pacific basin. Among them, TC Oli is one of the most devastating cyclones to have hit French Polynesia over the last 30 yr, having forced the evacuation of thousands of people and destroying over 280 houses in the Society and Austral Islands. It was associated a maximum sustained wind of 51 m s−1 (over a 10-min period), with wind gusts reaching 75 m s−1, and a minimum pressure at the center of 925 hPa (category 4 on the Saffir-Simpson scale). It lasted from 1 to 7 February 2010 and covered some 5000 km in the South Pacific Ocean. It impacted the island of Tubuai in the Austral Islands on 5 February at 1200 UTC. This island was precisely on TC Oli’s track: the eye was reported between 1400 and 1500 UTC. The cyclone had eased to a maximum sustained wind of 40 m s−1 (over a 10-min period).
In this paper, we will investigate the effect of Tropical Cyclone Oli on the ocean temperature using a variety of measurements. The cold SST in the wake of tropical cyclones is well known since the 1960s. The dominant processes responsible for the surface cooling induced by TCs have mainly been discussed through...