Time-frequency characteristics of the relationships between tropical Indo-Pacific SSTs

Song Yang, Xiaoli Ding, Dawei Zheng, Soo Hyun Yoo

Research output: Journal article publicationJournal articleAcademic researchpeer-review

14 Citations (Scopus)


In this study, several advanced analysis methods are applied to understand the relationships between the Niño-3.4 sea surface temperatures (SST) and the SSTs related to the tropical Indian Ocean Dipole (IOD). By analyzing a long data record, the authors focus on the time-frequency chaxacteristics of these relationships, and of the structure of IOD. They also focus on the seasonal dependence of those chaxacteristics in both time and frequency domains. Among the Niño-3.4 SST, IOD, and SSTs over the tropical western Indian Ocean (WIO) and eastern Indian Ocean (EIO), the WIO SST has the strongest annual and semiannual oscillations. While the Niño-3.4 SST has large inter-annual variability that is only second to its annual variability, the IOD is characterized by the laxgest semiannual oscillation, which is even stronger than its annual oscillation. The IOD is strongly and stably related to the EIO SST in a wide range of frequency bands and in all seasons. However, it is less significantly related to the WIO SST in the boreal winter and spring. There exists a generally weak and unstable relationship between the WIO and EIO SSTs, especially in the biennial and higher frequency bands. The relationship is especially weak in summer and fall, when IOD is apparent, but appears highly positive in winter and spring, when the IOD is unimportantly weak and even disappears. This feature reflects a caution in the definition and application of IOD. The Niño-3.4 SST has a strong positive relationship with the WIO SST in all seasons, mainly in the biennial and longer frequency bands. However, it shows no significant relationship with the EIO SST in summer and fall, and with IOD in winter and spring.
Original languageEnglish
Pages (from-to)343-359
Number of pages17
JournalAdvances in Atmospheric Sciences
Issue number3
Publication statusPublished - 1 May 2007


  • Coherence analysis
  • ENSO
  • Indian Ocean dipole
  • Time-frequency relationship

ASJC Scopus subject areas

  • Atmospheric Science


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