Unveiling PACE OCI's Hyperspectral Terrestrial Data Products

Imaging spectroscopy leverages narrow bandwidth radiance measurements to improve observations of Earth’s ecosystems. The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission’s Ocean Color Instrument (OCI) uses global, hyperspectral data to study not only the ocean, but also the land surface at ~1.2 km spatial resolution on a one- to two-day time scale. There are two PACE products immediately relevant to terrestrial science: the first is a suite of
atmospherically corrected surface reflectances at 50+ OCI bands, resolving spectral properties of the Earth more finely than previous multispectral missions. The second is a suite of ten vegetation indices, six of which are well-known heritage indices requiring only broadband reflectances to be calculated. The remaining four indices depend on narrow-wavelength measurements and are being produced for the first time globally with PACE OCI. These indices have been shown to relate to green vegetation amount, foliar pigments (chlorophylls, carotenoids, and anthocyanins), water content, photosynthetic light use efficiency, and snow cover. Data from the early months of the mission show OCI’s viability for terrestrial investigations – the instrument maintains and extends the historical multispectral data record while also generating novel hyperspectral results from which the mechanisms of Earth’s land surface can be further unraveled.