The Plankton, Aerosol, Cloud, Ocean Ecosystem Mission: Status, Science, Advances

Abstract

The Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission represents the National Aeronautics and Space Administration’s (NASA) 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, and ocean biological and biogeochemical data records, making essential ocean color measurements to further understand marine carbon cycles, food-web processes, and ecosystem responses to a changing climate, and 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 air and water quality and reducing uncertainties in climate and radiative forcing models of the Earth system. PACE observations will provide information on radiative properties of land surfaces and characterization of the vegetation and soils that dominate their reflectance. The primary PACE instrument is a spectrometer that spans the ultraviolet to shortwave-infrared wavelengths, with a ground sample distance of 1 km at nadir. This payload is complemented by two multiangle 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–land system. Here, we present an overview of the PACE mission, including its developmental history, science objectives, instrument payload, observatory characteristics, and data products.

Inversion of multiangular polarimetric measurements over open and coastal ocean waters: a joint retrieval algorithm for aerosol and water-leaving radiance properties

“…The aerosol and ocean surface representations are summarized in Table 2, where the aerosol volume distribution is represented as the summation of six size modes with three submodes of fine-mode aerosols and another three submodes of coarse-mode aerosols (Gao et al, 2018). The complex aerosol refractive index spectra for fine and coarse mode are represented by the principal component analysis (PCA) of aerosol refractive index spectral measurements (Shettle and Fenn, 1979;d'Almeida et al, 1991;Wu et al, 2015). Only the major spectral variation represented by the first order of the principle components is considered (Gao et al, 2018).…”

Phytoplankton Community Composition Determined From Co-variability Among Phytoplankton Pigments From the NAAMES Field Campaign

“…Pigment-based methods are well suited to link satellite measurements to surface ocean ecology at coarse resolution given the impact of phytoplankton pigments on absorption, which directly alters the shape and magnitude of remote sensing reflectance. However, these methods are limited by both the spectral resolution of the satellite and the composition of the HPLC dataset used to calibrate and validate the satellite models (i.e., Kramer and Siegel, 2019;Werdell et al, 2019). Based on the results presented here, a future satellite model of phytoplankton community composition built for the western North Atlantic Ocean using this HPLC dataset for calibration and validation could retrieve at most 5 distinct phytoplankton communities.…”

Retrieval of aerosol properties from Airborne Hyper Angular Rainbow Polarimeter (AirHARP) observations during ACEPOL 2017

“…November 2019 for a year-long mission beginning in February 2020; HARP2, a payload instrument for NASA's Plankton, Aerosols, Clouds, ocean Ecosystem (PACE) mission set to launch in the early 2023s (Werdell et al, 2019); and AirHARP, an airborne version of the HARP concept. In this paper, we focus on aerosol retrievals derived from measurements made from AirHARP as a proxy for these future space missions.…”

“…These include, in addition to 3MI, Research Scanning Polarimeter (RSP) (Cairns et al, 1999(Cairns et al, , 2003, Airborne Multiangle Spectro Polarimetric Imager (AirMSPI) (Diner et al, 2013), SPEX Airborne (Smit et al, 2019), Observing System Including PolaRisation in the Solar Infrared Spectrum (OSIRIS) which is a 3MI airborne simulator, and Hyper-Angular Rainbow Polarimeter (HARP) Mcbride et al, 2020). For a comprehensive review of the polarimetric remote sensing of atmospheric aerosols 80 based on MAPs, we encourage the readers to refer to several reviews in the literature Kokhanovsky et al, 2015;Remer et al, 2019). In this work, we focus on retrieval of aerosol properties using AirHARP data, the airborne version of HARP, from the NASA aircraft campaign, Aerosol Characterization from Polarimeter and Lidar (ACEPOL).…”