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Abstract:
Profiles of total absorption coefficient of sea water at 440 nm with Hobilabs a-Sphere integrating sphere instrument (excluding pure water absorption). Taken coincident with SBE19+ and ISUS (nitrate sensor) profiles. AC-9 profiles were taken right after a-Sphere profiles were completed.
In situ profiles of optical properties were made from a heated tent at the ice camp several hundred meters away from the ship.
Quality
Instrument was factory calibrated before and right after experiment. Data from corresponding CTD profiles were used for a temperature and salinity correction of spectral absorption data obtained with ac-9 and a-Sphere following Röttgers et al. [2014]. Absorption spectra from a-Sphere were smoothed to reduce the noise (LOESS method, Cleveland [1979]).
Data consists of 57 casts (profiles) with time, latitude and longitude and pressure (depth in meters) in the mat file. Data has be binned every 0.5 m with depth.
References: Cleveland, W. S. (1979), Robust locally weighted regression and smoothing scatterplots, Journal of the American statistical association, 74(368), 829-836.
Röttgers, Rüdiger, David McKee, and Christian Utschig. 2014. “Temperature and Salinity Correction Coefficients for Light Absorption by Water in the Visible to Infrared Spectral Region.” Optics Express 22 (21), 25093-25108. doi:10.1364/OE.22.025093