The NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Mission: An Emerging Era of Global, Hyperspectral Earth System Remote Sensing

The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission represents NASA’s next investment in satellite ocean
color and the study of Earth’s ocean-atmosphere system, enabling new insights into oceanographic and atmospheric
responses to Earth's changing climate. PACE objectives include extending systematic cloud, aerosol, ocean biological and
biogeochemical data records, making essential ocean color measurements to further understand marine carbon cycles and
ecosystem responses to a changing climate, as well as improving knowledge of how aerosols influence ocean ecosystems
and, conversely, how ocean ecosystems and photochemical processes affect the atmosphere. PACE objectives also
encompass management of fisheries, large freshwater bodies, and water quality and reducing uncertainties in climate and
radiative forcing models of the Earth system. PACE observations will also provide information on radiative properties of
land surfaces and characterization of the vegetation and soils that dominate their reflectance. The primary PACE
instrument – the Ocean Color Instrument (OCI) – is a hyperspectral imaging radiometer that spans the ultraviolet to
shortwave infrared, with a ground sample distance of 1-km at nadir. This includes continuous collection of spectra from
340 nm to 890 nm in 5 nm steps. The PACE payload is complemented by two multi-angle polarimeters with spectral
ranges that span the visible to near-infrared region. Scheduled for launch in late 2022-to-early 2023, the PACE observatory
will enable significant advances in the study of Earth’s biogeochemistry, carbon cycle, clouds, hydrosols, and aerosols in
the ocean-atmosphere system. We present a brief overview of the PACE mission, followed by a discussion of the
capabilities and design concept of OCI.