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Spectrally expansive absolute radiometry of celestial and aquatic targets

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This dataset contains absolute radiometric observations of aquatic and celestial targets spanning a spectral range of 313--1640nm. Data products were obtained using multispectral radiometers based on analog or digital components with similar hardware and processing (methods are documented in Houskeeper et al., 2023). Observations at individual wavebands were obtained objectively and independently. Radiometric observations of the Moon and the Sun were obtained at Mauna Loa (HI) and Mount Laguna (CA), and radiometric observations of aquatic targets were obtained in the Southern Ocean, Mission Bay (CA), San Pablo Bay (CA), Grizzly Bay (CA), and Lake Tahoe (CA and NV). Additional verification (e.g., from satellite matchups, model results, or alternate processing methodologies) are included when appropriate.

Description of the data and file structure

The datasets are summarized as follows:

SolarPhotometry.csv contains solar Langley observations from Mauna Loa and Mount Laguna. Observations are the natural log of instrument flux and are presented as a function of air mass. Celestial radiometry was obtained using the Optical Sensors for Planetary Energy (OSPREy) instrument suite at Mauna Loa, and the newest compact generation of the instrument suite (C-OSPREy) at Mount Laguna.

LunarPhotometry.csv contains Lunar Langley observations from Mauna Loa. Observations are the natural log of instrument flux and are presented as a function of air mass. Celestial radiometry was obtained using the OSPREy instrument suite.

AquaticRadiometry-SO.csv contains observations (lowest to highest) of the normalized water-leaving radiance (Lwn; units: uW cm^-2 nm^-1 sr^-1) as a function of wavelength. Shipboard observations were obtained using a manually pointed radiometer, the Biospherical Surface Ocean Reflectance System (BioSORS), in the Southern Ocean under overcast sky conditions and oligotrophic oceanic conditions. Verification observations are included via an optically simple (case-1) model, as well as via satellite matchups (MODIS and VIIRS), with the satellite matchups presented as averages since overcast conditions prevent direct matchups.

AquaticRadiometry-WUS.csv contains observations of Lwn obtained using above- and in-water radiometric instrumentation at Mission Bay (CA) and Lake Tahoe (CA and NV). Above-water observations were obtained using the Compact-Airborne Environmental Radiometers for Oceanography (C-AERO) radiometric instrument suite. In-water observations were obtained using the Compact-Hybridspectral Radiometer (C-HyR) instrument suite. SBA indicates above-water observations processed using the skylight-blocked approach (SBA).

AirborneRadiometry-WUS.csv contains observations of Lwn obtained from lowest safe altitude (LSA) airborne remote sensing surveys at Grizzly Bay (CA) and Lake Tahoe. For the Lake Tahoe observations, verification observations are provided using an optically simple (case-1) model. Observations of Lwn at 1245nm, obtained during an LSA airborne survey of San Pablo (CA) and Grizzly Bays, are included, with corresponding latitude and longitude values. Airborne observations were obtained using the C-AERO instrument suite.

Additional Information

Additional methodological details are provided in the associated publication:

• Houskeeper, Henry F., and Stanford B. Hooker. Extending aquatic spectral information with the first radiometric IR-B field observations. PNAS Nexus (Accepted).

Additional information on predictive dark-current (PDC) methods and glint discretization are provided in the following publications:

• Houskeeper, H.F., S.B. Hooker, and R.N. Lind. "Fourteen decades of linear responsivity for planetary radiometry.'' Journal of Atmospheric and Oceanic Technology (In Review).
• Hooker, S.B., H.F. Houskeeper, R.N. Lind, and K. Suzuki. "One- and two-band sensors and algorithms to derive aCDOM(440) from global above- and in-water optical observations." Sensors 21, no. 16 (2021): 5384. https://doi.org/10.3390/s21165384
• Houskeeper, H.F., S.B. Hooker, and R.M. Kudela. "Spectral range within global aCDOM(440) algorithms for oceanic, coastal, and inland waters with application to airborne measurements." Remote Sensing of Environment 253C (2021): 112155. https://doi.org/10.1016/j.rse.2020.112155
• Guild, L.S., R.M. Kudela, S.B. Hooker, S.L. Palacios, and H.F. Houskeeper. "Airborne radiometry for calibration, validation, and research in oceanic, coastal, and inland waters." Frontiers in Environmental Science 8, no.~585529 (2020): 209. https://doi.org/10.3389/fenvs.2020.585529

Additional information regarding in-water radiometry and field sampling is provided in the following publications:

• Hooker, S.B., A. Matsuoka, R.M. Kudela, Y. Yamashita, K. Suzuki, and H.F. Houskeeper. "A global end-member approach to derive aCDOM(440) from near-surface optical measurements." Biogeosciences 17, no. 2 (2020): 475-497. https://doi.org/10.5194/bg-17-475-2020
• Hooker, S.B., H.F. Houskeeper, R.M. Kudela, K. Suzuki, and R.N. Lind. "Verification and validation of hybridspectral radiometry obtained from an unmanned surface vessel (USV) in the open and coastal oceans." Special Issue, Recent Advances in Ocean Physics, Geochemistry and Biology from Unmanned Marine Vehicles in Remote Sensing 14, no. 5 (2022): 1084. https://doi.org/10.3390/rs14051084
• Houskeeper, H.F., S.B. Hooker, and Ky.C. Cavanaugh. "Spectrally simplified approach for leveraging legacy geostationary oceanic observations." Applied Optics 61, no. 27 (2022): 7966-7977. https://doi.org/10.1364/AO.465491

Additional information regarding the San Pablo Bay, Grizzly Bay, and Lake Tahoe field sampling and airborne campaigns can be accessed via Guild et al. (2021), Houskeeper et al. (2021), and via the following publication:

• Hooker, S.B., H.F. Houskeeper, R.M. Kudela, A. Matsuoka, K. Suzuki, and T. Isada. "Spectral modes of radiometric measurements in optically complex waters." Continental Shelf Research 219 (2021): 104357. https://doi.org/10.1016/j.csr.2021.104357

Additional information regarding hardware, software, and processing advances relevant to the instrumentation used herein can be accessed via the following publications:

• Hooker, Stanford B., Randall N. Lind, John H. Morrow, James W. Brown, Koji Suzuki, Henry F. Houskeeper, Toru Hirawake, and Elígio de Ráus Maúre. Advances in above-and in-water radiometry, volume 1: enhanced legacy and state-of-the-art instrument suites. No. NASA/TP–2018-219033/VOL. 1. 2018.
• Hooker, Stanford B., Randall N. Lind, John H. Morrow, James W. Brown, Raphael M. Kudela, Henry F. Houskeeper, and Koji Suzuki. Advances in above-and in-water radiometry, volume 2: autonomous atmospheric and oceanic observing systems. No. GSFC-E-DAA-TN68732. 2018.
• Hooker, Stanford B., Randall N. Lind, John H. Morrow, James W. Brown, Raphael M. Kudela, Henry F. Houskeeper, and Koji Suzuki. Advances in above-and in-water radiometry, volume 3: hybridspectral next-generation optical instruments. No. NASA/TP–2018-219033/VOL. 3. 2018.