Journal of the European Optical Society - Rapid publications, Vol 11 (2016)
A novel method of measuring upwelling radiance in the hydrographic sub-hull
Abstract
In this study we present a new method useful in collecting upwelling radiance (Lu) from a platform submerged in a hydrographic sub-hull or moon pool of a research vessel. The information analyzed here was obtained during a field campaign in the Northwestern European shelf seas aboard the new research vessel SONNE. As the platform was located at the center of the ship, there is minimal effect from pitch and roll which is known to influence upwelling radiance observations. A comparison of the measurements from this platform with a free falling hyperspectral profiler was performed to determine the degree of uncertainty that results from ship shadow. For given Lu(λ) in situ data we observed ±33% intensity deviations compared to profiling measurements that can be attributed to instrument shading during moon pool installation and environmental perturbations. Furthermore Lu(λ) in situ spectra variations were observed at lower wavelengths, therefore a form fitting algorithm was adapted to receive corresponding depths with identical spectral form from Lu(z, λ) profiler casts. During an east to west transect in North Sea with a schedule speed up to 12 knots in situ radiance reflectance rrs(7, λ) measurements at 7 meter depth were performed with this novel radiometer setup. In spite of any restrictions originating from the sub-hull installation, water masses mixing zone from CDOM dominated coastal waters in the Skagerrak Strait towards the open North Sea were successfully derived thus offering an underway applicable upwelling radiance sensing not suffering from sun glint or other typical restrictions of above water radiometer installations.
© The Authors. All rights reserved. [DOI: 10.2971/jeos.2016.16003]
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T. Platt, N. Hoepffner, V. Stuart, and C. Brown (eds.), ”Why ocean colour? The societal benefits of ocean-colour technology,” (IOCCG, Reports of the International Ocean-Colour Coordinating Group, No. 7, 2008).
J. Watson, and O. Zielinski (eds.), Subsea optics and imaging (Woodhead Publishing, Cambridge, UK, 2013).
O. Zielinski, J. A. Busch, A. D. Cembella, K. L. Daly, J. Engelbrektsson, A. K. Hannides, and H. Schmidt, ”Detecting marine hazardous substances and organisms: sensors for pollutants, toxins, and pathogens,” Ocean Sci. 5, 329–349 (2009).
S. P. Garaba, T. H. Badewien, A. Braun, A.-C. Schulz, and O. Zielinski, ”Using ocean colour remote sensing products to estimate turbidity at the Wadden Sea time series station Spiekeroog,” J. Eur. Opt. Soc.-Rapid 9, 14020 (2014).
C. Moore, A. Barnard, P. Fietzek, M. R. Lewis, H. M. Sosik, S. White, and O. Zielinski, ”Optical tools for ocean monitoring and research,” Ocean Sci. 5, 661–684 (2009).
G. N. Plass, T. J. Humphreys, and G. W. Kattawar, ”Color of the ocean,” Appl. Opt. 17, 1432–1446 (1978).
S. B. Hooker, G. Lazin, G. Zibordi, and S. McLean, ”An evaluation of above-and in-water methods for determining water-leaving radiances,” J. Atmos. Oceanic Technol. 19, 486–515 (2002).
J. L. Mueller, G. S. Fargion, C. R. McClain, S. Pegau, J. R. V. Zaneveld, B. G. Mitchel, M. Kahru, et al. (eds.), ”Ocean optics protocols for satellite ocean color sensor validation,” (NASA, revision 4, 2003).
S. P. Garaba, and O. Zielinski, ”An assessment of water quality monitoring tools in an estuarine system,” Remote Sens. Appl.: Soc. Environ. 2, 1–10 (2015).
E. L. Hestir, V. E. Brando, M. Bresciani, C. Giardino, E. Matta, P. Villa, and A. G. Dekker, ”Measuring freshwater aquatic ecosystems: The need for a hyperspectral global mapping satellite mission,” Remote Sens. Environ. 167, 181–195 (2015).
A. Tanaka, H. Sasaki, and J. Ishizaka, ”Alternative measuring method for water-leaving radiance using a radiance sensor with a domed cover,” Opt. Express 14, 3099–3105 (2006).
T. Suresh, M. Talaulikar, E. Desa, S. G. Prabhu Matondkar, T. S. Kumar, and A. Lotlikar, ”A simple method to minimize orientation effects in a profiling radiometer,” Mar. Geod. 35, 441–454 (2012).
J. Piskozub, ”Effect of ship shadow on in-water irradiance measurements,” Oceanologia 46, 103–112 (2004).
R. W. Spinrad, and E. A. Widder, ”Ship shadow measurements obtained from a manned submersible,” Proc. SPIE 1750, 372–383 (1992).
K. J. Waters, R. C. Smith, and M. R. Lewis, ”Avoiding ship-induced light-field perturbation in the determination of oceanic optical properties,” Oceanography 3, 18–21 (1990).
Hydrographic funnels operator manual, 696 D 0001 (Neptun Werft, 2013).
I. Reda, and A. Andreas, ”Solar position algorithm for solar radiation applications,” Sol. Energy 76, 577–589 (2004).
C. T. Weir, D. A. Siegel, A. F. Michaels, and D. W. Menzies, ”In situ evaluation of a ship’s shadow,” Proc. SPIE 2258, 815–821 (1994).
S. B. Hooker, and A. Morel, ”Platform and environmental effects on above-water determinations of water-leaving radiances,” J. Atmos. Oceanic Technol. 20, 187–205 (2003).
R. Leathers, T. V. Downes, and C. Mobley, ”Self-shading correction for upwelling sea-surface radiance measurements made with buoyed instruments,” Opt. Express 8, 561–570 (2001).
C. A. Stedmon, C. L. Osburn, and T. Kragh, ”Tracing water mass mixing in the Baltic–North Sea transition zone using the optical properties of coloured dissolved organic matter,” Estuar. Coast. Shelf S. 87, 156–162 (2010).
T. Kristiansen, and E. Aas, ”Water type quantification in the Skagerrak, the Kattegat and off the Jutland west coast,” Oceanologia 57, 177–195 (2015).