Transport through the Solomon Sea observed by Moorings and Inverted Echo Sounder with Bottom Pressures

The Solomon Sea, located between Papua New Guinea and the Solomon Islands in the western Pacific, is dominated by the northward flowing New Guinea Coastal Undercurrent (NGCUC). The NGCUC connects the subtropics to the equatorial region by acting as a conduit of water from the South Pacific to the Equatorial Undercurrent (EUC). Despite this important linkage, the structure and dynamics of the current system through the Solomon Sea are not fully understood. Since July 2012, moorings and bottom pressure sensors have been deployed at the western and eastern sides of the Solomon Sea allowing a continuous observation of the vertical structure of the current down to 500m depth along with the associated transport. The mean current has a maximum near 300m and the current fluctuates the most at the surface. Transport across the Solomon Sea has a seasonal pattern with a drastic change between April and August. Short-term variability can be as large as 15 Sv in a week or less. The available temperature and salinity profiles from moorings also permit identification of the sources of water coming into the Solomon Sea, whose transports can be distinguished. Finally, a technique is developed to reconstruct the transport and most of its vertical distribution based only on satellite altimetry and bottom pressure utilizing the vertical structure measured by moorings. The derived transport agrees quite well with the direct measurements suggesting the possibility of an economical monitoring system in the future.