This dataset contains the results of eigenanalyses conducted using apparent optical property observations of aquatic environments. The eigenanalyses were conducted to assess the primary sources of variability in the aquatic light field, and the results are associated with the Biogeosciences publication Houskeeper and Hooker (2025). Methodological details, including descriptions of the underlying datasets, plus post-processing and quality control, are provided in the associated publication. Brief descriptions plus additional methodological references are included below.

Associated Publication

Houskeeper, H.F. and S.B. Hooker. “The primacy of dissolved organic matter to aquatic light variability.” Biogeosciences (2025).

Dataset Summaries

Fig. 1: Eigenfunctions

The first three eigenfunctions for each of the underlying datasets, as well as the oligotrophic subset, are organized in sheets. Each sheet is associated with an underlying dataset or its oligotrophic subset corresponding to the sheet name. The initial column of each sheet represents the waveband characteristics of the underlying dataset.

Fig. 2: Field and Algorithmic Observations

Data products indicating Ca and aCDOM (440)
are presented for each of the underlying datasets, as applicable. Each sheet is
associated with an underlying dataset corresponding to the sheet name. Data
products are denoted as algorithmic or field observations, depending on
contemporaneous field observations where available. Algorithmic Ca is derived using the NASA OC4 algorithm, and algorithmic aCDOM (440) is derived using end-member analysis, with the applicable
equation and coefficients specified in the associated publication.

Fig. 3: Variance Explained

The variance explained by the first 6 eigenfunctions is presented for each of the underlying datasets. Summaries of the underlying datasets are presented below. Additional information is also shown for the data products presented in: Cael, B. B., Kelsey Bisson, Emmanuel Boss, and Zachary K. Erickson. “How many independent quantities can be extracted from ocean color?.” Limnology and Oceanography Letters 8, no. 4 (2023): 603-610.

Underlying Dataset Summaries

The analyses are based on underlying datasets, which are briefly summarized, with naming conventions indicating the associated publication journal and year, as follows:

RSE2021

Global (i.e., oceanic, coastal, and inland water) normalized water-leaving radiance (nLw) data products are derived from observations obtained using the digital C-OPS with C-PrOPS instrument suite (Houskeeper et al. 2021). The observations correspond to an average vertical sampling resolution (VSR) of 6.0 mm, indicating the depth intervals at which profile measurements were obtained, with a maximum VSR of 0.9 mm. Initial observations of the upwelling radiance are obtained at approximately 0.3 m depth, corresponding to the length of the downward-pointing radiance radiometer. Additional quality control and methodological details are provided in Hooker et al. (2020) and Houskeeper et al. (2021). The dataset includes contemporaneous observations of Ca and the absorption of colored dissolved organic matter at 440 nm, aCDOM(440). Spectral subsets of RSE2021 are named, as follows: UVN21 corresponds to the full spectral domain (i.e., is identical to RSE2021); VIS21 corresponds to the visible spectral domain (400-700 nm) data products from RSE2021; and UVN corresponds to the non-visible spectral domain (< 400 nm or > 700 nm) data products from RSE2021.

RSE2022

Oceanic and coastal ocean nLw data products are derived from spectrometer observations using rocket-shaped profilers and buoys (Kramer et al. 2022). The dataset is accessed via Kramer et al. (2021) and includes contemporaneous observations of Ca.

RSE2007

Oceanic nLw data products are derived from observations obtained using primarily analog free-falling instrument suites during open-ocean field campaigns, plus some coastal zone stations (Morel et al. 2007). The dataset includes contemporaneous observations of Ca.

For RSE2022 and RSE2007, which do not include contemporaneous observations of aCDOM(440), algorithmic estimates of aCDOM(440) are obtained using end-member analysis following Houskeeper et al. (2021) and as described in the associated manuscript. Oligotrophic subsets for each dataset are obtained by filtering observations associated with Chlorophyll a concentration (Ca) observations less than 0.5 mg m⁻³.

Additional Methodological References

Additional methodological details associated with the hardware, software, and sampling protocols for the RSE2021 dataset are provided in the following publications:

1. Houskeeper, H.F., S.B. Hooker, and R.N. Lind. “Expanded linear responsivity for Earth and planetary radiometry.” Journal of Atmospheric and Oceanic Technology 41, no. 11 (2024): 1093-1105. https://doi.org/10.1175/JTECH-D-23-0133.1
2. Houskeeper, Henry F., and Stanford B. Hooker. “Extending aquatic spectral information with the first radiometric IR-B field observations.” PNAS Nexus 2 no. 11 (2023). https://doi.org/10.1093/pnasnexus/pgad340
3. 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
4. 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
5. 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
6. 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
7. 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.” Remote Sensing 14, no. 5 (2022): 1084. https://doi.org/10.3390/rs14051084
8. 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
9. 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
10. 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. NASA/TP–2018-219033/VOL. 1. 2018.
11. 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. GSFC-E-DAA-TN68732. 2018.
12. 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. NASA/TP–2018-219033/VOL. 3. 2018.