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

MARCH 2008

Atmospheric and oceanic conditions during March 2008 reflected a moderate La Niña. Equatorial sea surface temperatures (SSTs) in the Pacific Ocean remained below average from west of the Date Line eastward to 120°W. However, these departures weakened during the month (Fig. T18), and the latest Niño-3.4 and Niño-4 index values were only slightly cooler than -1°C (Table T2). Meanwhile, the SST anomalies near the west coast of South America have been positive since February 2008 (Table T2, Figs. T9, T18).

The oceanic thermocline remained shallower than normal east of 140°W and continued to deepen in the region west of the Date Line (Fig. T16). Consistent with this structure, sub-surface temperature at thermocline depth remained below average (-1°C to -4°C) across the eastern equatorial Pacific, and above average west of 170°W (Fig. T17).

Strong low-level easterly anomalies persisted across the western and central equatorial Pacific during the month (Fig. T20, Table T1), which is consistent with the shallower-than-average thermocline in the central and eastern equatorial Pacific (Figs. T15, T16). These conditions were associated with enhanced convection (above-average rainfall amounts) across the Indian Ocean , Indonesia and the far western tropical Pacific, and a continuation of suppressed convection (below-average rainfall amounts) across the central equatorial Pacific (Figs. T25, E3). Consistent with these anomalies, the Tahiti – Darwin SOI remained positive (+1.1) (Table T1, Fig. T1), and the equatorial SOI was +2.4 (Fig. T2).

For the latest status of the ENSO cycle see the ENSO Diagnostic Discussion at: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.html