Please refer to the following document for additional information, including calibration procedures:


Slade, W.H, E. Boss, G. Dall'Olmo, M.R. Langner, J. Loftin, M.J., Behrenfeld, and C. Roesler, 2010. Underway and moored methods for improving accuray in measurement of spectral particulate absorption and attenuation. Journal of Atmospheric and Oceanic Technology, 27:10, 1733-1746.

This document may be downloaded from our website at:  http://misclab.umeoce.maine.edu/publications/scientific_articles.php or email us at emmanuel.boss@maine.edu.


We use a calibration independent technique to obtain particular absorption and attenuation by differencing measurements with a 0.2um filter from measurements made with no filter. Filters are exchanged weekly and flowtubes are cleaned about every other day to once a week.


Data provided are minute binned absorption data (dissolved values needed to obtain the particulate values are linearly interpolated to the time of particulate measurements). In coastal regions switching between filtered and unfiltered measurements is done in 30min cycles while in open ocean every 60min (50min total, 10min dissolved). We use the 3rd method of Zaneveld et al., 1994 to correct for scattering with 730nm as the null wavelengths simultaneously performing a residual temperature correction (see Slade et al., 2010). We have left spectra with negative absorption in the blue regions as these values are not significantly different from zero. In extreme cases we replace bad values with -9999.


In the rare cases where the c-side of the ac-9 failed, we use the 1st method of Zaneveld et al., 1994 to correct for scattering, assuming that the scattering spectra is flat and that absorption at 730nm is zero simultaneously performing a residual temperature correction.


Files of the same name with ap or cp appended to the end of the name go together.  Date, time, lat, lon, temperature, and salinity are repeated in these paired files, when available.

Standard deviations of the minute bins are reported with "_sd" appended to the end of the name.