Meetings: Documents

Aquarius SSS Optimum Interpolation Analysis for Global and Regional Studies
[12-Nov-2014] Melnichenko, O., Hacker, P., Maximenko, N., Lagerloef, G., and Potemra, J.
Presented at the 2014 Aquarius/SAC-D Science Team Meeting
A new high-resolution sea surface salinity (SSS) analysis has been produced at the International Pacific Research Center of the University of Hawaii using Aquarius Level-2 (swath) data from September 2011 to August 2014. The primary product is a weekly SSS analysis on a nearly-global 0.5-degree grid. The analysis method is optimum interpolation (OI) that takes into account analyzed errors on the observations, specific to the Aquarius instrument. The method also includes a large-scale correction for satellite biases, filtering of along-track SSS data prior to OI, and the use of realistic correlation scales of SSS anomalies. All these features of the analysis are shown to result in more accurate SSS maps, free from spurious structures. In particular, the method reduces the effects of relative biases between the Aquarius beams, which, if not properly accounted for, result in artificial north-south-striped patterns in mapped SSS fields. Also, the method eliminates most of the large-scale, space- and time-varying satellite biases relative to in-situ data, including spurious annual signals. A statistical comparison between the weekly OI SSS maps and concurrent buoy data demonstrates that the global root-mean-square error of the analysis is smaller than 0.2 psu for nearly all weeks for the 3-year period of comparison. The utility of the OI SSS analysis is also exemplified by the derived patterns of regional SSS variability.

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