Tropical Highlights - March 2007

 

The pattern of tropical sea surface temperature (SST) anomalies during March 2007 featured near-average temperatures across the western and central equatorial Pacific and colder-than-average temperatures over the eastern tropical Pacific (Fig. T18). Accordingly, the SST anomalies were negative in the Ni�o 1+2 and Ni�o 3 regions (latest values of -0.7 and -0.3, respectively) and zero in the Ni�o 3.4 region during the month (Table T2). Meanwhile, the Tahiti � Darwin SOI was slightly negative (latest value: -0.4), which is consistent with ENSO-neutral conditions (Table T1, Fig. T1).

The equatorial oceanic thermocline, measured by the depth of the 20�C isotherm, featured below average depths over the eastern Pacific and near average depths across the western and central Pacific (Figs. T15, T16).  Consistent with these conditions, temperatures at thermocline depth were 3-5�C below average over the eastern equatorial Pacific and near average across the western and central equatorial Pacific (Fig. T17).

During March 2007, low-level easterly anomalies (more than 3.0 m s^-1) were observed over the central equatorial Pacific and low-level westerly anomalies (more than 3.0 m s^-1) were present across the eastern tropical Indian ocean (Fig. T20). This circulation was associated with enhanced convection (above-average rainfall amounts) across northwestern Australia , Indonesia and western equatorial Pacific, and suppressed convection (below-average rainfall amounts) across the central equatorial Pacific (Figs. T25 and E3).

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