Quantifying the Dependence of Westerly Wind Bursts on the Large-Scale Tropical Pacific SST

• Published in: Journal of climate Vol. 20; no. 12; pp. 2760 - 2768
• Main Authors: Tziperman, Eli, Yu, Lisan
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 15.06.2007
• Subjects: Amplitude; Amplitudes; Atmospheric models; Atmospherics; Bursts; Climate models; Covariance; Covariance matrices; Dynamical systems; Earth, ocean, space; Eigenvectors; El Nino; El Nino events; El Nino phenomena; El Nino-Southern Oscillation event; Exact sciences and technology; External geophysics; Longitude; Marine; Meteorology; Parameters; Physics of the oceans; Probability theory; Sea surface; Sea-air exchange processes; Seasonal variation; Singular value decomposition; Southern Oscillation; Statistical variance; Stochasticity; Studies; Time series; Westerlies; Westerly wind bursts; Wind; Wind stress; Wind velocity; Winds and their effects; Equatorial Pacific; IS, Tropical Pacific; time series analysis; Wind field; Westerly wind; Marine atmosphere; Sea surface temperature; ocean-atmosphere interaction; Gust; El Nino; Correlation analysis; Predictability; Southern oscillation; Pacific Ocean; seasonal variations; Singular value decomposition
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/jcli4138a.1

The correlation between parameters characterizing observed westerly wind bursts (WWBs) in the equatorial Pacific and the large-scale SST is analyzed using singular value decomposition. The WWB parameters include the amplitude, location, scale, and probability of occurrence for a given SST distribution rather than the wind stressitself. This approach therefore allows for a nonlinear relationship between the SST and the wind signal of the WWBs. It is found that about half of the variance of the WWB parameters is explained by only two large-scale SST modes. The first mode represents a developed El Niño event, while the second mode represents the seasonal cycle. More specifically, the central longitude of WWBs, their longitudinal extent, and their probability seem to be determined to a significant degree by the ENSO-driven signal. The amplitude of the WWBs is found to be strongly influenced by the phase of the seasonal cycle. It is concluded that the WWBs, while partially stochastic, seem an inherent part of the large-scale deterministic ENSO dynamics. Implications for ENSO predictability and prediction are discussed.