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 is minute median binned particulate absorption and attenuation spectra (dissolved values needed to obtain the particulate values, are linearly interpolated to the time of particulate measurements). From year day 143 to 158, filtered data is collect for 5 minutes every 30 minutes. From year day 158 onward, filtered data is collected for 10 minutes out of every hour. In both cases, the last minute of filtered data is binned and used for interpolation. We use the 3rd method of Zaneveld et al., 1994 to correct for scattering using the closest instrument wavelength to 730nm as the null wavelength. We simultaneously performing a residual temperature and salinity correction (see Slade et al., 2010). The uncorrected value at the null wavelength is appended to end of each ap spectra in the data file. 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.

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.

Uncertainty files based on the standard deviation within each minute bin are also provided.