In spring 2010, just before the beginning of the
2010/11 La Niña event, positive SST anomalies were
broadly seen over the equatorial Pacific and the
tropical Indian Ocean, and convective activity was
above normal over the central-eastern equatorial
Pacific and the western tropical Indian Ocean (upper migration of cold water (negative temperature
anomalies) in the upper ocean, which sometimes
brings about the end of an El Niño event and triggers
the development of a La Niña event, was observed in
the equatorial Pacific (Fig. 3.1.5).