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PACE Validation Science Team

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Cownosed Rays swim past the Chesapeake Bay Tower station.
Cormorants roost on the Upper Deck of the Chesapeake Bay Tower station.
Solar Panels are installed on the Upper Deck of the Chesapeake Bay Tower station.
Nicole Trenholm perches in an abandoned raptor nest.
Chesapeake Bay Tower station WATERHYPERNET PI Kevin Turpie.
PANTHYR ("PAN-and-Tilt HYperspectral Radiometer") system and developer Dieter Vansteenwegen.
The deployed HyperPro Buoy is a tiny black speck against the rich blue of the Mediterranean Sea.
The HyperPro Buoy prepares for deployment in the Mediterranean Sea during a SO PACE cruise.
Alison Chase and Vittorio Brando (CNR-ISMAR) discuss station measurements with during a SO PACE Cruise.
PANTHYR ("PAN-and-Tilt HYperspectral Radiometer") Instrument Components installed on the Chesapeake Bay Tower station.
Patrick Gray next to CTD near Cape Sounion, Greece.
Tara Ocean sampling at last station near Cape Sounion, Greece.
Dolphins in the Gulf of Corinth, Greece.
Patrick Gray with Temple of Poseidon in background.
Principal Investigator (PI)PI InstitutionData ProductsSeaBASS Project NameProject TitleProject DescriptionCo-Investigators
Clarissa Anderson Scripps Institution of Oceanography, UCSDRadiometry, pigments, Phytoplankton Community Composition (PCC), Inherent Optical PropertiesPVST_CALCOFIValidating PACE with the California Cooperative Oceanic Fisheries Investigations (CalCOFI) Program
This project establishes the California Cooperative Oceanic Fisheries Investigations (CalCOFI), hosted at Scripps Institution of Oceanography (SIO), as a PACE validation program. Project Objectives are to: 1) collect a broad suite of biogeochemical and biological measurements on CalCOFI cruises for future use in developing, refining, and assessing advanced NASA data products; 2) co-locate in situ hyper- and multi-spectral measurements with the required validation measurement suite from CalCOFI stations; 3) Validate performance of in situ radiometry from the PACE observatory.
Rasmus Swalethorp, Brice Semmens, Greg Mitchell, Mati Kahru, Andy Allen, and Andrew Barton (all Scripps, UCSD)
Stephen P. Broccardo NASA AmesRadiometry and atmospheric measurementsPVST_SEASTARThe Sea-going Sky-Scanning Sun-tracking Atmospheric Research Radiometer
SeaSTAR is a robotic sun/sky photometer for deployment on ships at sea. The instrument has 14 filter-photodiode channels from 340nm to 2200nm, including the standard AERONET wavelengths. All wavelength channels are measured simultaneously every second, allowing multi-spectral aerosol optical depth (AOD) to be retrieved at high spatiotemporal resolution. The wide dynamic range of the analog amplifier design allows solar irradiance as well as sky radiance measurements to be made through the same fore-optics. The optical path incorporates polarizing filters on each channel which can be switched in or out as required.
The measurement head is mounted on a robust 3-axis robot to allow closed-loop sun-tracking based on a camera image of the sun. The tracking error is logged along with the measurement data, allowing the measurement quality to be assessed. An inertial measurement unit enables arbitrary pointing of the instrument in the celestial reference frame while compensating for any motion of the ship platform using feed-forward control. The third robot axis allows the measurement head to be rotated around the pointing axis. This enables polarized sky-scans to be completed over a range of scattering angles and degrees of polarization, allowing aerosol optical properties to be retrieved.
Jun Wang (University of Iowa)
Alison ChaseApplied Physics Laboratory, University of WashingtonRadiometry, Phytoplankton Community Composition (PCC), Inherent Optical PropertiesPVST_SOPACEShips of Opportunity for PACE (SO-PACE): Validation of water-leaving reflectances, IOPs, and plankton community metrics 
SO-PACE will make use of opportunistic instrument deployments on research vessels to produce measurements of hyperspectral Rrs spanning 350 – 750 nm using the pySAS system, a continuous above-water autonomous solar tracking platform to collect water-leaving and sky radiances and downwelling irradiance, from which Rrs is calculated. Complementary measurements of IOPs will be made using underway flow-through systems and using pumps that minimize particle damage. IOP measurements will provide several products including: chlorophyll-a concentrations and spectral absorption of phytoplankton (both derived from particulate absorption), and spectral backscattering coefficients. The slope of particulate attenuation will provide estimates of trends in both bulk particle and phytoplankton size distributions. Concentrations of chlorophyll-a as well as additional phytoplankton accessory pigments will be estimated from both particulate absorption and Rrs spectra. Additionally, discrete water samples will be collected from flow-through systems and prepared for onshore laboratory HPLC analysis of phytoplankton pigments. Continuous measurements of phytoplankton communities will be made using two well-established instruments: an Imaging FlowCytobot (IFCB) and a SeaFlow (a continuous flow cytometer). These two instruments will also be deployed on shipboard flow-through systems, and have a combined range of ~ 0.6-150 microns for quantitative phytoplankton assessment.
Peter Gaube (UW-APL), Emmanuel Boss (UMaine), Ginger Armbrust (UW), François Ribalet (UW)
Robert FosterNaval Research Laboratory (NRL)Radiometry, pigments, Inherent Optical Properties, chlorophyll-a, atmospheric measurements, Particle Size Distribution (PSD)PVST_POLPolarimetric Validation of the PACE Observatory
The Naval Research Laboratory (NRL) and the City College of New York (CCNY) operate a comprehensive suite of instrumentation to measure and characterize the uncertainty of polarized radiation, as well as particle size distributions (PSDs), particle shape characterization and imaging, advanced chlorophyll fluorescence analysis, and seawater inherent optical properties (IOPs) and constituents. Measured attenuation (c) and absorption (a) coefficients of water and the degree of linear polarization (DoLP) above the surface derived from measurements of polarized radiances at Hyper-Angular Research Polarimeter #2 (HARP2) wavelengths will be used for the validation of a newly developed neural network algorithm for the retrieval of the c/a ratio from combined Ocean Color Instrument (OCI) and HARP-2 measurements (Agagliate et al., Frontiers in Remote Sensing, 2023).
Ahmed El-Habashi (NRL), Alex Gilerson (CCNY)
Jason R. GraffOregon State UniversityRadiometry, pigments, Phytoplankton Community Composition (PCC), Inherent Optical Properties, primary productivity, fluorescence, and a suite of carbon measurementsPVST_PBRPace Validation Science Team: Particles and Biological Rates
The project is focused on data collection for the NASA PACE validation efforts. Specifically, our core targeted observables are phytoplankton carbon biomass (Cphyto), total particulate organic carbon (POC) concentration, net primary production (NPP), and chlorophyll fluorescence quantum yields (φf) as well and inherent optical properties and radiometry. 
Toby Westberry, Kimberly Halsey, Michael Behrenfeld (all OSU)
Brice K. GrunertCleveland State University, OhioRadiometry, pigments, Inherent Optical Properties, hydrology, carbon measurementsPVST_PRINGLSPACE Radiometry and IOPs for Novel Great Lakes Science
The Laurentian Great Lakes provide extensive optical and trophic variability across diverse ecosystems, from environments challenged by current and legacy nutrient pollution and continuing water quality impairments, e.g., harmful algal blooms (HABs) and hypoxia, to relatively pristine aquatic systems with emerging water quality concerns such as Lake Superior. This project will conduct high density sampling of the Great Lakes in space and time to provide a diversity of reflectance spectra broadly representative of the fundamental inherent optical properties (IOPs) and biogeochemical conditions observed across inland and coastal systems globally. Station locations are responsive to in situ conditions and potential for PACE validation, but are generally located in Lake Erie’s western and central basins, southwestern Lake Michigan and Green Bay, and the central basin and the western arm of Lake Superior. Sampling uses coastal class vessels that enable rapid transit between stations and range in size from 25 to 70 ft. Data collected includes above water radiometry (SVC HR-512i), discrete spectral absorption (ap, aph, aNAP, aCDOM), hyperspectral backscattering (Sequoia hyper-bb), physical and optical biogeochemical variability (YSI EXO2 water quality sonde), and discrete biogeochemical parameters (HPLC pigments, DOC, POC, and SPM). Data will be collected in every month of the year over the course of a three year period, ensuring seasonal matchups for PACE OCI science data products in the winter and shoulder seasons that remain chronically under observed.
Liane S. GuildNASA Ames Research CenterAirborne and surface/profiling radiometry, atmospheric measurements, pigments, PCC, Inherent Optical Properties (IOPs), carbon measurementsPVST_AIRSHARPAirborne asSessment of Hyperspectral Aerosol optical depth and water-leaving Reflectance Product Performance for PACE
We will have combined airborne and field sampling at PACE overpass time over two sampling periods October 2024 and May 2025, spanning a wide range of aerosol and ocean states for Monterey Bay, California. Likely potential aerosol conditions include, but not limited to, maritime aerosol, wildfire smoke, long range Asian dust transport, and clear air (Zhao et al., 2013, Lewis et al., 2010, Mardi et al., 2018, Allan et al., 2004, VanCuren 2003). Expected maritime conditions include, but are not limited to, low productivity cold waters, algal blooms, riverine outflow, and turbid waters. The study site has dramatic conditions exacerbated by the changing climate and a recent history of significant fire seasons (Filoncyk et al., 2022), extreme precipitation conditions, namely drought, atmospheric rivers and subsequent changes in riverine outflow, and other climate change impacts such as harmful algal blooms and far-reaching riverine plumes. We achieve PACE validation with hyperspectral (e.g., HyperPro II water optical profiling and 4STAR-B atmospheric transmittance) and aligned contemporary radiometric measurements (C-AIR water-leaving radiance from aircraft and C-OPS water optical profiling). The latter contemporary ocean color detectors have much higher dynamic range than OCI. This unique combination of airborne and surface and profiling instrumentation and water sampling can provide high-accuracy validation of the PACE mission sensors in a globally-representative range of oceanic conditions. The repeated airborne observations can provide the calibration and validation over larger areas and time by collecting measurements over a larger spatial domain during a satellite overpass and different seasons, overcoming the problem of limited spatial coverage presented by using solely ship stations and moored buoy systems.
Samuel E. LeBlanc (NASA Ames), Raphael M. Kudela (UCSC), Anthony Bucholtz ( Naval Postgraduate School)
Nils HaentjensUniversity of MaineRadiomety, Attenuation coefficientsPVST_VOSDIUPValidation of Ocean Surface Downwelling Irradiance and Its Underwater Propagation for the PACE Mission
This project contributes to the validation of global surface radiation products and diffuse attenuation coefficients (Kd) generated by the PACE mission, essential for quantifying net primary production. The radiation products include instantaneous, daily mean, spectral, band-integrated, planar, and scalar fluxes, in particular daily mean photosynthetically available radiation (PAR). In-situ observations are gathered through a network of automatic stations measuring hyperspectral downward planar irradiance (Ed(0+)) at selected AERONET-OC sites, and BGC-Argo profilers equipped with hyperspectral Ed sensors. 
Jing Tan (Scripps, UCSD), Emmanuel Boss (University of Maine), Robert Frouin (Scripps, UCSD)
Johnathan HairNASA-LangleyValidate PACE atmospheric aerosol and ocean-related products; and apply and archive the operational MAPP algorithm to RSP polarimeter data PVST_HSRL_RSPPACE Validation Using Airborne Lidars and the Research Scanning Polarimeter
For validation of advanced PACE aerosol and ocean products, we will use the following combination of airborne instruments: a full suite of state-of-the-art in situ aerosol instrumentation, the state-of-the-art airborne RSP polarimeter with accuracies and spectral ranges that match or exceed those of the PACE instruments in the VIS and SWIR, and the state-of-the-art airborne HSRL lidars that provide highly accurate vertically-resolved aerosol and hydrosol profiles. The in situ measurements furthermore will be combined to produce ambient aerosol products suitable for PACE validation. This combination of airborne in situ, polarimeter, and HSRL lidar data will allow us to validate advanced PACE-retrieved column aerosol properties, ocean products, and provide critically important vertically-resolved aerosol and ocean data to create collocated and curated validation data sets. These combined data sets will allow us to deeply investigate the uncertainties of and characterize any discrepancies in PACE aerosol and ocean products, including in the advanced aerosol optical and microphysical property retrievals from the PACE polarimeters, and the UV and VIS ocean products from the PACE Ocean Color Instrument (OCI).
Sharon Burton (NASA LaRC), Brian Collister (NASA LaRC), Joseph Schlosser (NASA LaRC), Snorre Stamnes (NASA LaRC), Jacek Chowdhary (Columbia University)
Fernanda Henderikx-FreitasUniversity of Hawaii at MānoaRadiometry, Inherent Optical Properties, pigments, fluorescence, and aerosolsPVST_HOTPACELeveraging the Hawaii Ocean Time-series program for validation of the PACE Mission in oligotrophic waters
In this project, we leverage the near-monthly, 5-day long expeditions to oligotrophic waters approximately 100 km from Oahu, Hawaii, conducted by the Hawaii Ocean Time-series (HOT) program. We will participate in ~30 HOT cruises across all seasons over a 3-year period, amounting to ~ 150 days of high-quality collection of a suite of essential parameters for PACE Mission validation 
Angelicque White (University of Hawaii)
Eric J. HochbergArizona State University (ASU)/ Bermuda Institute of Ocean Sciences (BIOS)RadiometryPVST_PSSTPACE Sargasso Sea Team
Measurements of Rrs in the Sargasso Sea, leveraging Hydrostation-S, BATS, and BVAL cruises. Other cruises to be used opportunistically. Planned duration of 2.5 years, encompassing 100+ potential match-ups with PACE.
Norm Nelson (UCSB), Rodney Johnson (ASU/BIOS), Stéphane Maritorena (UCSB), Eric Rehm (Sea-Bird Scientific)
Amy E. MaasArizona State University (ASU)/ Bermuda Institute of Ocean Sciences (BIOS)Particle Size Distribution (PSD), pigments, Phytoplankton Community Composition (PCC)PVST_BATS_PLANKTONPACE Validation BATS plankton
The data provided by this project is the abundance and taxonomic information for the 5-300 µm planktonic community captured via imaging with a FlowCam. We will additionally analyze a duplicate subset of water samples from the same cast as BATS HPLC depths (0-250 m), sending these pigment samples to GSFC. Target depths for both the FlowCam and HPLC include surface, 40, 80, 120, 160, and 200. The FlowCam will be run in both trigger and automated mode with two different settings (4X and 20X) per bottle sample to enumerate and classify photosynthetic organisms. In addition, we will analyze the standard phytoplankton net tows (0-175 mwo, 120-150 m depth, 35 µm mesh net) following the same protocol using the FlowCam to ensure enumeration of the larger phytoplankton taxonomic groups. BATS data (including duplicate HPLC data) can be pointed to from SEABASS but will retain it’s standard BCO-DMO DOI. 
Leocadio Blanco-Bercial, Rodney Johnson (ASU/BIOS)
Stéphane MaritorenaUCSBRadiometry, pigmentsPVST_SBCRCoastal campaigns for the validation of the OCI water-leaving reflectance data product  
Rapid response field campaigns (small boats, small crew) to measure radiometry in the Santa Barbara Channel when sea and sky conditions are optimal for matchups. Process and deliver in situ high quality radiometric data for the validation of the reflectance data product of the PACE OCI instrument.
David Siegel (UCSB)
Catherine MitchellBigelow Laboratory for Ocean SciencesCalcification, pigments, Phytoplankton Community Composition (PCC), Inherent Optical Properties, primary productivity, fluorescence, and a suite of carbon measurementsGNATSGulf of Maine North Atlantic Time Series 
The Gulf of Maine North Atlantic Time Series (GNATS) was established in 1998. It runs from approximately Portland, Maine, to Yarmouth, Nova Scotia, across the central Gulf of Maine. We’ve typically used ships of opportunity to target clear sky days to ensure concurrent satellite and ship-based measurements. GNATS measures a suite of optical, biogeochemical, biological and hydrographic properties of surface waters. GNATS has received funding through various NASA programs, with the most recent funding to support PACE postlaunch validation activities. We plan 8 cruises per year from 2025 – 2027, and will focus on collecting biogeochemical and inherent optical property data. 
Colleen MouwUniversity of Rhode IslandRadiometry, pigments, Phytoplankton Community Composition (PCC), Inherent Optical Properties, fluorescence, and a suite of carbon measurementsPVST_NCSValidation of PACE radiometry and science data products in the U.S. Northeast Continental Shelf in partnership with NOAA
Routine NOAA surveys will be utilized that transect the entire U.S. Northeast Continental Shelf Ecosystem to capture a large volume of validation data across the U.S. Northeast Continental Shelf. Full characterization of AOPs and IOPs via continuous above-water radiometry, profiled radiometry, continuous flow-through IOP observations, and discrete subsamples. Phytoplankton measurements across a broad size range with a flow cytometer and Imaging Flow CytoBot (IFCB), supplemented with discrete HPLC pigment samples. 
Kimberly Hyde (NOAA Northeast Fisheries Science Center)
Michael OndrusekNOAA NESDISRadiometry, Inherent Optical PropertiesVIIRS_ValidationOcean Color Validation Support of the PACE Mission through Multi-institutional Synergy 
This project seeks to provide Remote Sensing Reflectance (Rrs) and Inherent Optical Properties (IOPs) field measurements for PACE validation. Measurements will be collected onboard the NOAA Annual VIIRS calibration and validation cruises and during the PACE-PAX experiment. Rrs will be collected using the Sea-Bird Scientific HyperPro data in profile and buoy mode, as well as data from the Spectral Vista Coorporation (SVC) and ASD FieldSpec 4 handheld spectroradiometers. IOPs will be collected using a Sea-Bird Scientific spectral absorption and attenuation sensor (ac-s).
David English (USF), Sherwin Ladner (NRL)
Nicole PoultonBigelow Laboratory for Ocean SciencesPigments, Phytoplankton Community Composition (PCC), Inherent Optical Properties, Particle Size Distribution (PSD), and a suite of carbon measurementsBIOGOSHIPBioGOSHIP: PACE Validation using Ships of Opportunity
Bio-GO-SHIP aims to become an international collaboration to measure, understand, and predict the distribution and biogeochemical role of pelagic plankton communities. The project leverages the global-reaching GO-SHIP platform and its complementary hydrographic measurements. The mission of Bio-GO-SHIP is to quantify the molecular diversity, size spectrum, chemical composition, and abundances of plankton communities across large spatial, vertical, and eventually temporal scales. This will be achieved through systematic, high-quality, and calibrated sampling of ‘omics, plankton imaging, particle chemistry, and optical techniques as operational oceanographic tools. Integration with regular GO-SHIP measurements and their analyses of the physical and chemical environment will allow us to understand (and eventually predict) how plankton communities respond to ocean changes and how biological processes feeds back on carbon, oxygen and nutrient cycles.  
Nicole Poulton (Bigelow Laboratory), Catherine Mitchell (Bigelow Laboratory), Jason R. Graff (OSU)
Mike SayersMichigan Technological UniversityRadiometry, Inherent Optical Properties, pigmentsPVST_GLOCGreat Lakes Ocean Color Validation
We will employ a three-tiered strategy to acquire PACE OCI validation data in the Great Lakes that includes recurring seasonal and weekly monitoring cruises, a dedicated “super-site”, and other cruises of opportunity. All validation activities will be linked to externally funded monitoring programs, leveraging ship-time and lab processing capabilities. All measurement activities will follow best practices established in the IOCCG protocol series and will include documented uncertainty.  Specifically, we will collect a full suite of inherent and apparent optical properties along with paired laboratory measured biochemical parameters. Discrete station vertical profiles along with flow-through surface observations will be made.
Kenneth SinclairNASA Goddard Institute for Space Studies & Columbia UniversityCloud validation data productsPVST_CLOUDS_VALPerformance Assessment of Advanced Cloud Data Products from OCI, HARP-2 and SPEXone Instruments 
The overarching goal of this project is to establish reliable validation and uncertainty estimates of PACE cloud data products to demonstrate their capabilities to the scientific community and support future scientific investigations. Our plan to validate PACE cloud products centers on using case studies that incorporate a variety of instrument measurements over a range of cloud types and conditions using established approaches and statistical methods. OCI and HARP2 data products will be geolocated and gridded for comparison to airborne in situ and remote sensing measurements. This performance assessment will focus on data collected during the PACE Postlaunch Airborne eXperiment (PACE-PAX), the Arctic Radiation-Cloud-Aerosol-Surface-Interaction Experiment (ARCSIX) and the Earth Care Validation; Tropical Oceans and Organized Convection (EC-TOOC). PACE-PAX instruments that are fundamental to this analysis are the PACE-proxy instruments that include the Airborne Hyper-Angular Rainbow Polarimeter (AirHarp), the Portable Remote Imaging Spectrometer (PRISM) and Push-broom Imager for Cloud and Aerosol Research and Development (PICARD) instruments. Also included in PACE-PAX is the High-Spectral Resolution Lidar (HSRL-2) system that will provide measurements of cloud top height, cloud vertical structure, optical thickness, an in-cloud extinction profile and has sensitivity to cloud phase using a combination of the layer integrated depolarization and integrated attenuated backscatter measurements. The state-of-the-art Research Scanning Polarimeter (RSP) measures intensity and polarization in nine spectral bands across 152 viewing angles, making it capable of retrieving all of the PACE advanced cloud products including, but not limited to: cloud layer detection, optical thickness, the effective radius and variance of the cloud droplet size distribution, liquid water path, cloud phase and the cloud droplet number concentration. A G-band microwave radiometer capable of accurately measuring liquid water path will take part in ARCSIX and be valuable for assessing the performance of the OCI and HARP2 LWP retrievals. An in-situ suite of cloud probes is included in PACE-PAX and ARCSIX and will provide a crucial component to our validation by providing independent and direct measurements of cloud vertical structure, cloud phase, droplet concentration, as well as measurements of cloud size distributions. In-situ measurements will be collocated with complementary remote sensing measurements before being compared with PACE’s advanced products in our multifaceted validation approach. A third objective is to produce and publicly archive L2 cloud data products from airHARP L1C data that are fit-for-purpose and suitable for further scientific analysis.  
Mikhail Alexaudrov, Igor Geogdzhager (all Columbia University)
Omar TorresNASA GSFCRadiometry and atmospheric measurementsPVST_UVAAPPACE validation of UV Aerosol Absorption Properties 
Three Modified Yankee Multi-Filtered Rotating Shadow Band Spectrometers (M-MFRSR) will be deployed at three locations to measure UV aerosol absorption properties at 340nm and 380 nm. Aerosol parameters to be derived are single scattering albedo (SSA) and Aerosol Absorption Optical Depth (AAOD). Instruments will be deployed at operational Aerosol RObotic NETwork (AERONET) sites. AERONET derived information on aerosol optical depth (AOD), surface albedo, and particle size distribution (PSD) will be used as input to the inversion of M-MFRSR total (direct plus diffuse), diffuse, and direct (total – diffuse) multi-spectral planar irradiance measurements.
Nickolay Krotkov, Gordon Labow (all NASA GSFC)
Si-Chee TsayNASA GSFCRadiometry and atmospheric measurementsPVST_SMARTValidating PACE aerosol columnar properties and OCI water-leaving radiances from ground-based network spectroradiometer measurements 
Multiple units of in-house built SMART-s (Spectral Measurements for Atmospheric Radiative Transfer-spectrometer, 330–870 nm at ~0.8 nm resolution), as a part of NASA/Pandora network with extended spectral range, will be deployed to support PACE validation over oceanic waters (Eureka Oil Platform, CA; ~8 miles off the coast of Long Beach, CA) and seasonal transported Asian dust, southeastern biomass-burning smoke, and locally generated industrial air pollutants such as trace gases, precursors, and aerosols (Taiwan) sites. Specifically, we propose to accomplish the following two tasks:
1. To evaluate OCI's atmospheric-corrected water-leaving radiance/reflectance: Since the scans of SMART-s are very flexible and programmable, we will initially adopt the AERONET-OC operational criteria (e.g., IOCCG, 2019; Zibordi et al., 2021) for data continuity and consistency checks; then, after accumulating enough lessons learned from SeaPRISM, the advantage of SMART-s spectrometry will help improving the spatial-spectral-temporal sampling efficiency and effectiveness for PACE/OCI intercomparison (validation) and application. These water-leaving radiance/reflectance will be integrated with OCI's spectral response functions to meet their spectral range (i.e., 17 bands in 350–710 nm at 15 nm bandwidth; 665/678 nm at 10 nm bandwidth) and uncertainty requirements.
2. To validate PACE's aerosol and cloud products: We will utilize well-calibrated SMART-s' direct-Sun and sky measurements with SMART-s published methods (Jeong et al., 2018, 2020, and 2022) to retrieve columnar properties of aerosols (e.g., spectral AOD, single-scattering albedo, and Ångström exponent, fine-mode fraction of complex index of refraction) and abundance of trace gases (O3, NO2, H2Ovapor). By leveraging the assets of the upcoming 7-SEAS (Seven SouthEast Asian Studies, 2024–2026, Taiwan in collaborating NASA AERONET/ MPLNET) international field campaigns, SMART-s measurements can be maximized for improving scientific understanding and validating PACE/OCI products.
Kevin TurpieUMBC/NASA GSFCRadiometry PVST_WATERHYPERNET_CBTWATERHYPERNET Chesapeake Bay Tower Station 
The Chesapeake Bay Tower station is part of the WATERHYPERNET, a network of automated spectrometers worldwide measuring above-water water-leaving reflectance (ρw). Measurements are taken every 20 minutes following IOCCG protocols, including sky spectral irradiance using an spectrometer with a whole sky IFOV and sky spectral radiance and water spectral radiance using a slewing spectrometer.  These measurements are processed into ρw at the Royal Belgian Institute or Natural Sciences.  The spectrometers are calibrated annually at Tartu Observatory. 
Xiaodong ZhangUniversity of Southern MississippiRadiometry, Inherent Optical PropertiesPVST_AUV_GOMAutonomous Radiometric Validation of PACE’s OCI in the Gulf of Mexico
Validate PACE’s OCI remote sensing reflectance using uncrewed autonomous vessel measuring water-leaving radiance with two methods along with inherence optical properties in the Gulf of Mexico
Joaquim GoesLamont-Doherty Earth ObservatoryRadiometry, pigments, Phytoplankton Community Composition (PCC), Inherent Optical Properties, fluorescence, and a suite of carbon measurementsPVST_NORTHERN_INDIAN_OCEANArabian Sea bio-optical and biogeochemical data for ocean color validation
This project will collect high-quality, bio-optical, and biogeochemical data for validation of advanced satellite products from PACE OCI for the Arabian Sea, a highly under-sampled region of the world’s oceans, now experiencing dramatic ecosystem changes from human activities and climate-change. Over the past two decades, the base of the food chain of this monsoonal-driven ecosystem has transitioned from diatoms to one dominated by the mixotrophic dinoflagellate, Noctiluca scintillans (Noctiluca) that forms intense and widespread blooms visible from space. Capturing such phytoplankton transitions has been the pursuit of ocean color missions for more than three decades, and with its hyperspectral capabilities, NASA’s PACE mission can now provide unprecedented insight into the response of phytoplankton communities to global pressures. Despite the dramatic rates at which the Arabian Sea has been changing, it remains among the most optically under-sampled of global water bodies. As part of this effort, we will leverage our long-standing ties with colleagues in India to collect high quality, high resolution (sub-pixel scale), continuous, underway and discrete bio-optical measurements to validate standard and advanced ocean products from PACE, essential to advance our understanding of vulnerable marine ecosystems and their response to anthropogenic change. As part of this activity, we plan to participate in one pre-monsoon cruise (2025) led by Space Applications Centre, ISRO, India, and two post-bloom ONR led cruises in April-May of 2024 and in April-May 2025. The pre-monsoon cruises are being undertaken as part of an Indo-US study focused on establishing triggers of the southwest monsoon rainfall season over the Indian sub-continent. Some of the data shared under this DOI is part of the Arabian Sea Marine environment through Science and Advanced Training (EKAMSAT) collaborative effort between the Ministry of Earth Sciences, Govt. of India and the Office of Naval Research. EKAMSAT commenced with a pilot study in June 2023. The pilot data is being archived under the SeaBASS experiment EKAMSAT_Pilot_ASTRAL (DOI: 10.5067/SeaBASS/EKAMSAT_Pilot_ASTRAL/DATA001) and can downloaded here: EKAMSAT_Pilot_ASTRAL - SeaBASS
Maria Tzortziou (CCNY), Helga Gomez (LDEO), Jinghui Wu (LDEO), Khalid Alhashmi (SQU), Mini Raman (ISRO)