On 19 August 2016, the R/V Revelle began survey operations that will run through the middle of September 2016 at the site of the SPURS2 study region in a high rainfall region the Eastern Tropical Pacific. This is the second phase of the NASA-funded Salinity Processes in the Upper Ocean Regional Study (SPURS) project, a science process study and series of oceanographic field campaigns that aim to elucidate key mechanisms responsible for near-surface salinity variations in the oceans. Employing a suite of advanced sampling technologies coupled to regional circulation models, SPURS seeks to quantify the relative significance of circulation, evaporation, precipitation over a range of scales for representative areas of the open ocean. In so doing, it addresses the fundamental role the ocean plays in global water cycle budgets and its relationship to climate.

The ongoing Revelle cruise is the first of up to three SPURS2 cruises spanning a complete annual cycle in 6-month intervals focused within a 3x3 degree survey areas centered at 10N, 125W. It aims to better understand physical processes that influence upper-ocean salinity in a low-salinity, precipitation dominated region of the eastern tropical Pacific (ETP).  This area is heavily influenced by rainfall associated with the intertropical convergence zone (ITCZ). It has a shallow thermocline and strong seasonally-varying currents, making sampling a challenge.  SPURS leverages satellite salinity measurements from SMAP, SMOS and other remote sensing datasets (e.g. SST, altimetry, scatterometry, precipitation).   A suite of in situ (field) observations will be guided by a data-assimilating, regional circulation model to address these questions within this high variability, dynamic region.