Climatology of hot events in the western equatorial Pacific

We investigated the climatology of hot events (HEs) in the western equatorial Pacific. HEs are characterized by well-organized high sea surface temperatures (SSTs). We proposed a method for identifying HEs using a space–time-dependent threshold with a minimum areal size of 2 × 10⁶ km², and with a duration (period) of >6 days. We thus identified 71 HEs from the optimally interpolated SST dataset during 2003–2011. Their mean duration, areal size, and amplitude were 18.14 days, 6.30 × 10⁶ km², and 0.33 °C, respectively. On average, the HEs developed more slowly than they decayed. They were distributed within the equatorial band to the subtropical Pacific (20°S–30°N), with an eastward extension to 150°W. In particular, the HEs occurred most frequently along the northern coasts of New Guinea and the Solomon Islands to 180°E. Seasonal variation in the HE distribution was observed: a northward shift during boreal summer and a southward shift during boreal winter. The distribution of HE occurrences corresponded to the climatological SST of the western Pacific warm pool. HEs occurred under conditions of low wind speeds (~2.56 m/s) and high levels of solar radiation (~225 W/m²). However, since the high levels of solar radiation occurred over the entire area of the western equatorial Pacific during HE periods, the low wind speed distribution became a key factor in the occurrence of HEs in the western equatorial Pacific. Seasonal shifts in wind speed and solar radiation were found to influence the seasonal shift in HE distribution.