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 2009

Weak La Niña conditions continued during March 2009, as negative sea surface temperature (SST) anomalies persisted the central and east-central equatorial Pacific Ocean (Fig. T18).  The latest monthly SST index was -0.5°C in the Niño-3.4 region, and -0.3°C in the Niño-4 region (Table T2).

The oceanic thermocline along the equator, measured by the depth of the 20°C isotherm, remained shallower than average in the far eastern Pacific and deeper than average across the western Pacific during March (Figs. T15, T16). Consistent with these conditions, temperatures were 1-5^oC below average at thermocline depth in the far eastern Pacific (Fig. T17).

Convection remained suppressed over the central equatorial Pacific Ocean and enhanced across Indonesia during March 2009 (Figs. T25, T26 and E3). Collectively, this combination of oceanic and atmospheric conditions reflects a weakening of La Niña.

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