[15-May-2020] The Physical Oceanography Distributed Active Archive Center (PO.DAAC) is pleased to announce the availability of additional datasets from the NASA SPURS-2 field campaign. Following prior releases of twenty one SPURS-2 datasets, this fourth release includes a further two new datasets: the R/V Revelle underway pCO2 and SPURS central mooring data. The SPURS (Salinity Processes in the Upper Ocean Regional Study) project is a NASA-funded oceanographic process study and associated field program that aims to elucidate key mechanisms responsible for near-surface salinity variations in the oceans. SPURS employs a suite of state-of-the-art in-situ sampling technologies that, combined with remotely sensed salinity fields from the Aquarius/SAC-D, SMAP and SMOS satellites, provide a detailed characterization of salinity structure over a continuum of spatio-temporal scales. While SPURS-1 focused on the salinity maximum region of the sub-tropical N. Atlantic, SPURS-2 concentrated on the dynamic and seasonally variable, rainfall-dominated region of the eastern tropical Pacific centered at 10°N, 125°W. The SPURS-2 campaign involved two month-long cruises by the R/V Revelle in August-September 2016 and October-November 2017 combined with complementary sampling on a more continuous basis over this period by the schooner Lady Amber. Twenty-seven datasets will likely comprise the complete SPURS-2 collection, twenty-three of which have been finalized and are now available via the PO.DAAC. Further releases of SPURS-2 datasets will occur in the coming months. The SPURS-2 datasets are described, discoverable and accessible via the PO.DAAC data portal. Further information on SPURS is available from the project website and also via the SPURS field campaign page on the PO.DAAC portal. 10.5067/SPUR2-PCO20 | 10.5067/SPUR2-MOOR1 Lindstrom, E.J., J.B. Edson, J.J. Schanze, and A.Y. Shcherbina. 2019. SPURS-2: Salinity Processes in the Upper-ocean Regional Study 2. The eastern equatorial Pacific experiment. Oceanography 32(2):15–19, https://doi.org/10.5670/oceanog.2019.207. Please contact podaac@podaac.jpl.nasa.gov or visit the PO.DAAC Forum.