Tropical Highlights - June 2007

 

Tropical sea surface temperatures (SSTs) during June 2007 were near-average across the western and central equatorial Pacific and colder-than-average over the eastern tropical Pacific (Fig. T18). This pattern is reflected in negative values of the Niño 1+2   (-1.4) and Niño 3 (-0.5) region SST indices (Table T2). Meanwhile, the Tahiti – Darwin SOI became slightly positive (latest value: +0.2) for the first time since December 2006 (Table T1, Figs. T1). These conditions indicate a continuation of ENSO-neutral conditions.

The equatorial oceanic thermocline during June, measured by the depth of the 20ºC isotherm, featured a continuation of below-average depths over the eastern equatorial Pacific and near-average depths across the western and central equatorial Pacific (Figs. T15, T16). As a result, temperatures in the eastern equatorial Pacific remained generally 1-3ºC below average at thermocline depth (Fig. T17).

During June 2007, low-level easterly anomalies (more than 3.0 m s^-1) were observed across the tropical Indian Ocean and the western and central equatorial Pacific (Fig. T20). The latter anomalies have persisted since February (Fig. T13), and are consistent with the shallower-than-average thermocline farther east. This wind pattern was also associated with enhanced convection (above-average rainfall amounts) across Indonesia , the western tropical Indian Ocean and the Arabian Sea , and a continuation of suppressed convection (below-average rainfall amounts) across the central and eastern equatorial Pacific (Figs. T25, 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