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Climate Diagnostics Bulletin
Climate Diagnostics Bulletin - Home Climate Diagnostics Bulletin - Forecast Climate Diagnostics Bulletin - Extratropics


  Tropical Highlights

  Table of Atmospheric Indices  (Table 1)

  Table of Oceanic Indices  (Table 2)

  Time Series

  Time-Longitude Sections

  Mean & Anomaly Fields

  Appendix 1: Outside Contributions

Tropical Highlights


The pattern of tropical sea surface temperature (SST) anomalies

Tropical Highlights - October 2017



Sea surface temperatures (SSTs) during October 2017 were below-average across most of the central and eastern equatorial Pacific (Fig. T18, Table T2). The latest monthly Niņo indices were -0.1°C for the Niņo 4 region, -0.5°C for the Niņo 3.4 region, and -1.3°C for the Niņo 1+2 region (Table T2, Fig. T5). The depth of the oceanic thermocline (measured by the depth of the 20°C isotherm) was below-average over much of the eastern equatorial Pacific (Figs. T15, T16), and the corresponding sub-surface temperatures were 1-4°C below average (Fig. T17).


Also during October, the lower-level trade winds were near-average across the equatorial Pacific while the upper-level westerly winds were above-average over much of the central and eastern equatorial Pacific (Table T1, Figs. T20, T21). Meanwhile, convection was enhanced over the Maritime Continent and suppressed over the central equatorial Pacific (Figs. T25, E3). The latest Tahiti minus Darwin Southern Oscillation Index (SOI) was +0.9 (Table T1). Collectively, these oceanic and atmospheric anomalies reflect the onset of La Niņa conditions.


For the latest status of the ENSO cycle see the ENSO Diagnostic Discussion at:

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