Tropical Highlights � February 2014

 

 

�During February 2014, sea surface temperatures (SSTs) were below-average across the eastern equatorial Pacific (Fig. T18, Table T2). The latest monthly Ni�o indices were -0.6�C for the Ni�o 3.4 region and -0.8�C for the Ni�o 1+2 region (Table T2, Fig. T5). Consistent with these conditions, the depth of the oceanic thermocline (measured by the depth of the 20�C isotherm) remained slightly below-average across the eastern equatorial Pacific (Figs. T15, T16).

Also during February, the low-level easterly trade winds remained near-average across the central and eastern equatorial Pacific and below-average over the western Pacific (Table T1, Fig. T20). Meanwhile, tropical convection remained enhanced over western Pacific and suppressed over the central equatorial Pacific and western Indonesia (Figs. T25, E3). Collectively, these oceanic and atmospheric anomalies reflect a continuation of ENSO-neutral conditions.

Since August 2013, the equatorial Pacific Ocean has featured considerable intra-seasonal variability in response to a series of equatorial oceanic Kelvin waves. Upwelling Kelvin waves produce a cooling of the surface and sub-surface temperatures, while downwelling Kelvin waves produce a warming. During early February, an upwelling Kelvin wave had reached the west coast of South America, producing cooling in that region. By late February, a downwelling Kelvin wave had emerged and reached the central equatorial Pacific, resulting in a significant sub-surface warming in that region (Fig. T17).

 

 

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