Tropical Highlights - February 2006

 

The pattern of global tropical sea surface temperature (SST) anomalies during February featured negative anomalies in the east-central equatorial Pacific, with SST anomalies of -0.6 in the Niño 3.4 and Niño 4 regions (Fig. T18, Table T2). Meanwhile, the SST anomalies in the Niño 1+2 region became positive for the first time since June 2005 (Fig. T18, Table T2). The Tahiti - Darwin SOI (latest value -0.2, Table T1, Fig. T1) was slightly negative, in response to higher-than-average pressure over Darwin . The latter is consistent with suppressed convection during February over the western tropical Pacific, including northern Australia (Fig. T25).

The oceanic thermocline, measured by the depth of the 20°C isotherm along the equator, featured deeper-than-average depth in the western-central Pacific and shallower-than-average depth in the eastern Pacific during February (Figs. T15, T16). Consistent with these conditions, equatorial oceanic temperatures at thermocline depth were 2-3^oC above average across the western-central equatorial Pacific and 2-5^oC below average across the eastern equatorial Pacific (Fig. T17).

During February, near-average low-level winds were observed over the eastern equatorial Pacific, while low-level easterly anomalies (more than 3.0 m s^-1) were observed over the central equatorial Pacific (Fig. T20). In the global tropics, enhanced convection (above-average rainfall amounts) was observed over the vicinity of SPCZ and across the eastern tropical North Atlantic (Figs. T25, T26 and E3).