The ocean surface circulation with all its time-space complexity is the upper limb of the oceanic mass transport. Surface currents carry heat (climate), plankton (marine biology), plastic (pollution), and affect any socio-economic activity at sea (merchant shipping, renewable energy production, Oil & Gas operations). Yet, the global circulation is monitored through satellite remote-sensing only indirectly. We present here recent achievements in the derivation of the surface velocity from the combination of altimetry, gravimetry, optical, passive microwave, and numerical wind data. These developments have been carried out through CNES/CLS projects as well as during the GlobCurrent project (funded by the ESA User Element Program). Operational products are now available through CMEMS MULTIOBS component, and experimental products are available through AVISO and GlobCurrent portals. We show that the high-resolution sea surface temperature data (SST) from satellites can improve the velocity estimation by as much as 30% with respect to initially optimized geostrophic and Ekman combinations. The correction method is based on the inversion of the surface heat equation: this is the first time that such a tracer-derived technique is applied globally and can easily be implemented in operational production. The drifting buoy velocity database from AOML is extensively used as ground-truth data for calibration and validation. We discuss the differences as well between several candidate satellite L4-datasets used in the method, and more generally on the importance of the upstream products. We also place this study in the context of future satellite missions such as SWOT and SKIM (as of now a project in review) that will potentially generate some breakthrough for global circulation monitoring.
Global Ocean Surface Circulation Monitored through Synergy between Multi-Satellite Measurements
2019
Abstract
The ocean surface circulation with all its time-space complexity is the upper limb of the oceanic mass transport. Surface currents carry heat (climate), plankton (marine biology), plastic (pollution), and affect any socio-economic activity at sea (merchant shipping, renewable energy production, Oil & Gas operations). Yet, the global circulation is monitored through satellite remote-sensing only indirectly. We present here recent achievements in the derivation of the surface velocity from the combination of altimetry, gravimetry, optical, passive microwave, and numerical wind data. These developments have been carried out through CNES/CLS projects as well as during the GlobCurrent project (funded by the ESA User Element Program). Operational products are now available through CMEMS MULTIOBS component, and experimental products are available through AVISO and GlobCurrent portals. We show that the high-resolution sea surface temperature data (SST) from satellites can improve the velocity estimation by as much as 30% with respect to initially optimized geostrophic and Ekman combinations. The correction method is based on the inversion of the surface heat equation: this is the first time that such a tracer-derived technique is applied globally and can easily be implemented in operational production. The drifting buoy velocity database from AOML is extensively used as ground-truth data for calibration and validation. We discuss the differences as well between several candidate satellite L4-datasets used in the method, and more generally on the importance of the upstream products. We also place this study in the context of future satellite missions such as SWOT and SKIM (as of now a project in review) that will potentially generate some breakthrough for global circulation monitoring.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
