An Evaluation of Ship Data in the Equatorial Western Pacific

Abstract

Theoretical and observational studies suggest that the equatorial western Pacific plays an important role in the origin and maintenance of the El Niño-Southern Oscillation phenomenon. Historical data within this critical region are sparse except for a scattering of island stations and a merchant shipping lane along 155°E. The usefulness of ship data along this track is assessed utilizing exploratory data analysis and analysis of variance. Systematic biases are revealed in the surface wind, pressure and sea surface temperature measurements. The noise level in the data is quantified using standard error estimates and signal-to-noise ratios associated with various time averages. It is shown that zonal wind is capable of detailing synoptic-scale variations. However, meridional wind, surface pressure and sea surface temperature are better suited for estimating lower frequency variations.