Marine gravity data observed by JAMSTEC shipboard gravimeters in the seas around Japan

Abstract

　The Japan Agency for Marine-Earth Science and Technology （JAMSTEC） has published observation data and sample information obtained by research vessels and submersibles （DARWIN; https://www.godac.jamstec.go.jp/darwin/en/）. These observation data include geophysical, meteorological, physical, and chemical oceanographic data, and have been processed and quality controlled. The marine gravity data observed by shipboard gravimeters constitute one such data set. The relative gravity measurements observed by shipboard gravimeters have been converted to absolute gravity values, and the calculated free-air gravity anomalies can be downloaded from the data site. However, the marine gravity data have only been published on a cruise-by-cruise basis, and no integrated data have been published; in addition, no previous study has integrated JAMSTEC's shipboard gravimeter data. In this study, we constructed the JAMSTEC marine gravity data set for the area around Japan by integrating previously published JAMSTEC shipboard gravimeter data from more than 700 cruises. During the process of the integration, some problems were found in the published data; to deal with these problems, we reprocessed the data to improve the accuracy and reduce the inconsistencies.