Circulation and water mass transformations in the southwest Pacific Low Latitude Western Boundary Currents

The Low Latitude Western Boundary Currents of the Southwest Pacific establish a major connection between the subtropics and the equator. They cross the semi-enclosed Solomon Sea southeast of Papua New Guinea, resulting in a large variability due to the strong boundary currents encountering rough topography. As a result, the water mass properties are influenced during their transit with downstream effect on equatorial water properties. Two oceanographic multidisciplinary cruises have been completed in July 2012 and March 2014 to characterize currents, water properties and their modifications in the Solomon Sea as part of the CLIVAR/SPICE program. We will present the thermocline, intermediate and deep pathways and water mass transformations using measurements of salinity, oxygen, nutrients and velocities along with an inverse box model result. On the equator side of the Solomon sea, Mooring arrays in key straits provide estimates of transports and water mass property variations over 3 years. We will present an inter-comparison of the equatorward transports with a 20-year times series analysis from a high resolution model (1/36°). Finally, we will assess the impact of the transit and its variability through the Solomon Sea.