CoAuthors

Shailen Desai (Jet Propulsion Laboratory, California Institute of Technology, USA); Andy Wu (Jet Propulsion Laboratory, California Institute of Technology, USA); Scott Stalin (NOAA, Pacific Marine Environmental Laboratory, USA)

After an unprecedented 30-yr run, the Harvest experiment as it is conventionally known has come to an end. The oil platform, located 10 km off the coast of central California near Point Conception, is slated for decommissioning and the scientific observation systems on the structure are no longer operating. Against the backdrop of an uncertain shutdown schedule, the platform observational record was accurately maintained for the first two years of the Sentinel-6 Michael Freilich mission. We provide updated CALVAL results from this mission and discuss them in the context of the long-term record dating back to the launch of TOPEX/Poseidon (T/P) in 1992.

The decommissioning of the platform has been anticipated for years, and the long-planned transition of the CALVAL function to regional infrastructure in the Southern California bight is well underway. Advanced GNSS buoys, moored within 1-2 km of the platform, provide continuous observations of sea-surface height, and zenith wet troposphere. Additional GNSS buoys, returning from the SWOT postlaunch ocean campaign, will be repurposed for denser regional observations in this area. A new tide gauge is operating near the GNSS site at Vandenberg Space Force Base boat dock. Installed by University of Hawaii under the auspices of NOAA, the tide gauge is located about 10 km from the platform along the same ground track that passes by the platform (by virtue of the original design of the T/P 10-d repeat orbit.) We provide early results from these new observation systems and discuss implications for preserving this crucial long-term climate record.