Shipboard gravity meter data are tied to absolute gravity value using JAMSTEC bas, Yokosuka Japan. After 1-min resampling, the data are shifted and Etovos corrected. Free air anomaly is calculated by subtracting normal gravity formula (WGS84). The data with large Etovos correction ( > 3mGal/min) or slow ship speed ( < 3 knot) are removed. NO DRIFT CORRECTION WAS DONE.