Abstract
Diffuse attenuation coefficient (DAC) of sea water is an important parameter in ocean thermodynamics and biology, reflecting the absorption capability of sea water in different layers. In the Arctic Ocean, however, sea ice affects the radiance/irradiance measurements of upper ocean, which results in obvious errors in the DAC calculation. To better understand the impacts of sea ice on the ocean optics observations, a series of in situ experiments were carried out in the summer of 2009 in the southern Beaufort Sea. Observational results show that the profiles of spectral diffuse attenuation coefficients of seawater near ice cover within upper surface of 50 m were not contaminated by the sea ice with a solar zenith angle of 55°, relative azimuth angle of 110°⩽φ⩽115° and horizontal distance between the sensors and ice edge of greater than 25 m. Based on geometric optics theory, the impact of ice cover could be avoided by adjusting the relative solar azimuth angle in a particular distance between the instrument and ice. Under an overcast sky, ice cover being 25 m away from sensors did not affect the profiles of spectral DACs within the upper 50 m either. Moreover, reliable spectral DACs of seawater could be obtained with sensors completely covered by sea ice.
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References
Deser C, Teng H Y. 2008. Evolution of Arctic sea ice concentration trends and the role of atmospheric circulation forcing, 1979–2007. Geophysical Research Letters, 35(2): L02504, doi: 10.1029/2007GL032023
Gordon H R. 1985. Ship perturbation of irradiance measurements at sea. 1: Monte Carlo simulations. Applied Optics, 24(23): 4172–4182
Gordon H R, Ding K Y. 1992. Self-shading of in-water optical instruments. Limnol Oceanogr, 118: 491–500
Haas C, Nicolaus M, Willmes S, et al. 2008. Sea ice and snow thickness and physical properties of an ice floe in the western Weddell Sea and their changes during spring warming. Deep Sea Research: Part II, 55(8–9): 963–974
Helliwell W S, Sullivan G N, Macdonald B, et al. 1990. Ship shadowing: model and data comparisons. In: Ocean Optics X Proceedings Orlando: SPIE, 55–71
Kwok R, Cunningham G F, Wensnahan M, et al. 2009. Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008. Journal of Geophysical Research, 114(C7): C07005, doi: 10.1029/2009JC005312
Kwok R, Rothrock D A. 2009. Decline in Arctic sea ice thickness from submarine and ICESat records: 1958–2008. Geophys Res Lett, 36(15): L15501, doi: 10.1029/2009GL039035
Liou K N. 2002. An Introduction to Atmospheric Radiation. San Diego: Academic Press, 1210
Mobley C D. 1994. Light and Water: Radiative Transfer in Natural Waters. San Diego: Academic Press, 36–37
Mueller J L, Fargion G S, McClain C R, et al. 2002. Ocean Optics Protocols for Satellite Ocean Color Sensor Validation. Revision 4. Maryland: NASA, 13
Smith R C, Baker K S. 1984. The Analysis of Ocean Optical Data I, In: Ocean Optics VII Proceedings. Orlando: SPIE, 119–126
Smith R C, Baker K S. 1986. Analysis of Ocean Optical Data II. In: Ocean Optics VIII Proceedings. Orlando: SPIE, 95–107
Voss K J, Nolten J W, Edwards G D. 1986. Ship shadow effects on apparent optical properties. In: Ocean Optics VIII Proceedings. Orlando: SPIE, 186–190
Waters K J, Smith R C, Lewis M R. 1990. Avoiding ship-induced light-field perturbation in the determination of oceanic optical properties. Oceanography, 3(2): 18–21
Weir C T, Siegel D A, Michaels A F, et al. 1994. In situ evaluation of a ship’s shadow. In: Ocean Optics XII Proceedings. Orlando: SPIE, 815–821
Zibordi G, Ferrari G M. 1995. Instrument self-shading in underwater optical measurements: experimental data. Applied Optics, 34(15): 2750–2754
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Foundation item: The National Natural Science Foundation of China under contract No. 41206174; China Postdoctoral Science Foundation under contract No. 2012M511546; the Chinese Polar Scinece Strategy Fund under contract No. 20110204.
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Li, T., Zhao, J. An impact assessment of sea ice on ocean optics observations in the marginal ice zone of the Arctic. Acta Oceanol. Sin. 33, 24–31 (2014). https://doi.org/10.1007/s13131-014-0551-1
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DOI: https://doi.org/10.1007/s13131-014-0551-1