NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission:

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1 NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission: revolutionizing studies of global biogeochemistry and carbon cycles in the ocean(land)-atmosphere system Antonio Mannino1, Jeremy Werdell1, Brian Cairns2 NASA GSFC1 and GISS2 Acknowledgments: PACE Team, Kirk Knobelspiesse, Jeff Puschell, Nick Tufillaro, Chris Hostetler pace.gsfc.nasa.gov 1

2 What is PACE? aerosol optical thickness ocean chlorophyll normalized land vegetation index Broadly speaking, PACE has two fundamental science goals: (1) Extend key systematic ocean color, aerosol, & cloud climate data records (2) Address new & emerging science questions using its advanced capabilities Required: Ocean Color Instrument (OCI) And so much more+ Preferred: Polarimeter OCI cloud fraction 2

3 But,Earth s due to natural & human drivers,the our planet is changing. atmosphere moderates Sun s radiation, creating a climate, enabling our planet support life. From jobs to food to recreation to to regulating climate, the ocean is vital to all life on Earth. These changes impact Earth s weather, climate, & biogeochemistry in our oceans, and thus, life on Earth. 3

4 Understanding & protecting our ecosystems are essential to sustaining the global economy ~40% of the world s population lives within 100 km of a coast 1 Fisheries & aquaculture support ~12% of the world s livelihoods 2 Ocean economy contributed >$282B to US GDP & provided >2.8M jobs 3 Commercial value of US fisheries from coral reefs exceeds $100M 4 US harmful algal bloom events have average impact of $50M each year UN Environment Programme / SEDAC (2012) UN Food & Agricultural Organization (2014) NOAA National Ocean Service NOAA National Marine Fisheries Service WHOI, Anderson et al

5 Oceanic cons*tuents: changing in response to natural drivers & human acaviaes but, ocean color signals are small & differenaaang between consatuents requires addiaonal informaaon MODIS image: Arabian Sea, March 2,

6 Dark ocean compared to bright land & clouds Different groups Image stripes Sun glint SOLUTION: Tilt- Capable Hyperspectral UV- Vis- NIR Scanner with SWIR bands (OCI Ocean Color Instrument) Absorbing aerosols MODIS image: Arabian Sea, March 2,

7 The step from multi-spectral radiometry to spectroscopy is not an incremental one it s a quantum leap Why not just add more bands to a conventional instrument design? Just as there are 1000s of kinds of land plants, there are 1000s of kinds of phytoplankton, each with different absorption spectra; only an instrument that sees all wavelengths offers an opportunity to truly monitor fisheries, identify harmful algal blooms, & understand the land-ocean-atmosphere carbon cycle Absorbance (m -1 ) Coccolithophore Chlorophyte Cyanobacteria Diatom MODIS bands vs spectroscopy Wavelength (nm) 7

8 Aerosols & clouds: largest uncertainty terms in climate radiaave models but, aerosol, cloud, climate interacaons are complicated and difficult to observe MODIS image: Libya coast, October 26,

9 Aerosols & clouds: largest uncertainty terms in climate radiaave models Varied op*cal proper*es Varied contrasts Varied al*tudes but, aerosol, cloud, climate interacaons are complicated and difficult to observe MODIS image: Libya coast, October 26,

10 OCI atmospheric improvements over heritage VIIRS RGB + OMPS Aerosol Index Higher spatial resolution than many heritage products UV + oxygen-a bands to estimate concentrations & absorption magnitudes, not just an index VIIRS bands PACE bands Two 2-µm bands improve retrievals of cloud thermodynamic phase From Coddington et al. 2016, in preparation. Deeper red indicates improved probability of detection of ice phase 10

11 PACE: a quantum leap What makes PACE so advanced relative to other ocean color instruments? The PACE ocean color instrument will be the first ever to include all of the following: 2-day global coverage at 1-km hyperspectral radiometry from the ultraviolet (350 nm) to near-infrared (885 nm), complete downlink of 5 nm spectral resolution data SWIR bands (0.94, 1.25, 1.38, 1.61, 2.13, 2.26 µm) a single science detector to inhibit image striping SNRs that rival or exceed anything built previously Total calibrated instrument artifacts < 0.5% at top-of-atmosphere fore / aft tilt to avoid Sun glint semi-monthly lunar calibration + on-board solar diffuser mechanisms VIIRS OLCI / Sentinel-3 OLI / Landsat-8/9 MSI / Sentinel-2 PACE * only NACP bands March used 28, 2017 for ocean color shown Spatial Spectral * Temporal Detectors 750 m global 300 m global m coastal 1000 m global 7 bands from nm 1.24, 1.61, 2.25 µm 21 programmable bands from nm 5-9 bands from nm 1.60, 2.20 µm 115 bands from nm 1.25, 1.61, 2.13, 2.26 µm 2-day nadir view 3-day nadir view 16-day nadir view 2-day ±20 tilt multiple 16 rotating telescope multiple pushbroom multiple pushbroom single 1 rotating telescope 11

12 PACE Data Products OCI Atmospheric data products Spectral aerosol optical depth Cloud layer detection Cloud top pressure Liquid & ice cloud optical depth Liquid & ice cloud effective radius Shortwave radiation effect Polarimeter data products Aerosol particle size distributions Aerosol refractive index Aerosol single scattering albedo Aerosol shape & non-spherical fraction Aerosol layer height Cloud optical depth Cloud liquid particle size distributions Cloud ice particle shape & roughness Cloud top & base height And many other data products (land) Standard OCI Ocean data products Spectral ocean water-leaving reflectances Chlorophyll-a Inherent Optical Properties (a s & b s) PAR Diffuse attenuation coefficient Particulate Organic Carbon Particulate Inorganic Carbon Fluorescence Line Height Baseline Advanced OCI data products Phytoplankton community structure Phytoplankton physiology parameters Photosynthetic pigments Primary/community production Dissolved Organic Carbon Particle abundances Particle size distributions Carbon fluxes & export 12

13 Possible Terrestrial Data Products Heritage (non-thermal) data products (MODIS, VIIRS) Vegetation indices, LAI, PAR, BRDF * albedo, Reflectance, GPP & NPP, etc. Vegetation stress & nutrient status Plant pigments Plant functional types etc. See PACE Science Definition Team Report for Terrestrial Ecology Science enabled by PACE 13

14 Ocean Color Instrument Hyperspectral Scanner Main Optical Bench Image from: 14

15 Multi-angle polarimetry adds two extra dimensions of information to study the (oceans &) atmosphere Reflectance Multiple view angles Polarized Reflectance Degree of Linear Polarization 15

16 Polarimeters - Emerging Technologies Most polarimeters use one of four polarimetric analysis techniques Sequential: Spectral modulation: 3MI on Metop-SG A, ISRO s PAM AirSPEX from SRON operates on ER-2 Temporal modulation: Amplitude split: AirMSPI on NASA ER-2 and MAIA (EVI-3) Glory APS and HARPP from UMBC HARP: Hyper-Angular Rainbow Po (NASA ESTO InVEST) 16

17 Polarimetry Analysis Techniques Sequential Spectral modulation Temporal modulation Amplitude split 17

18 PACE Science Summary PACE is unlike any other ocean color mission planned to be flown in the 2020 s by any agency; it fills a substantial void The current ocean color instrument concept provides a major leap forward in capabilities for the ocean color community; by itself, it will provide a wealth of information not currently available or planned to become available to this community A polarimeter provides a leap forward in capabilities for the atmospheric community it also provides a benefit to the ocean color community, making the combination of instruments a major contribution to science 18

19 Geostationary Ocean Color - Emerging Technologies Hyperspectral UV-Vis-NIR-SWIR Instruments GLIMR (EVI-4; UNH/Raytheon/GSFC) Geostationary Littoral Imaging Radiometer Hyperspectral UV-Vis-NIR-SWIR (141 bands) ~300 m spatial resolution Sub-hourly scanning & full-disk imaging Cutting-edge SNR & dynamic range for ocean color Science: sub-diurnal coastal processes, landocean exchange, episodic events, etc. MOS (Airborne & Geo concept) Multi-slit Optimized Spectrometer with Polarimetry (Ball) Hyperspectral UV-Vis-NIR 4 slits (3 polarized on airborne) Airborne sensor flown across the San Francisco delta and coastal regions surronding South Korea (KORUS-OC and -AQ) Filter Wheel Radiometer UV-Vis-NIR-SWIR (~50 bands) ~300 m spatial resolution Sub-hourly scans of CONUS coastal waters & Great Lakes Breadboard of functional filter wheel mechanism (GSFC) 19

20 Lidar - Emerging Technologies vertical profiles of ocean particles CALIPSO lidar provides proof-of-concept CALIPSO Demonstrated that lidar has the sensitivity to provide global ocean properties from space (Behrenfeld et al. 2013, GRL) CALIPSO record provides fills in high latitude regions MODIS undersampled by ocean color (Behrenfeld et al., Nature Geosci., 2017) CALIPSO does not provide depth-resolved information or independent measurement of b bp and K d Next Step: High Spectral Resolution Ocean Lidar High Spectral Resolution lidar provides depth-resolved retrieval of b bp and K d (and quantities derived from them) Capability demonstrated with NASA airborne HSRL-1 instrument: SABOR 2014 (Hair et al., EPJ Web of Conferences. Vol. 119) NAAMES 2015 &

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