Dataset: CDOM Absorption Spectra

See: SO-GasEx cruise report, Section 5.7.8 ppgs 52-53

CDOM Absorption Spectra from CTDs
Operation description:
Multiple-wavelength absorption measurements using WPI UltraPath
spectral absorbance system with 200cm pathlength liquid waveguide.

Sampling times and locations:
Samples collected from regular CTD casts, at nominal depths of 5, 10,
20, 30, 50, and 100m.

Data products:
CDOM absorption spectra from 250-700nm
CDOM absorption at 440 nm
slope of absorption spectra

Data are presented in a separate file for each CTD cast.
Each file is identified by the CTD cast number.
Data are presented as an array of absorption (ag, units of 1/m)
for each wavelength between 250-700 nm, at each of the sampled depths.
Notation is ag_xm where x is the nominal depth of the samples.
Also provided in each sheet are the CDOM absorption at 440 nm (1/m)
and slopes of the absorption spectra (1/m/nm) for each depth.

Analytical method:
Samples filtered through 0.2µ nucleopore filters prior to measurement.
Milli-Q water used as reference with salinity-based offsets (refractive index)
correction applied. Sample temperatures were equilibrated to ambient temperature
(as was Milli-Q). Absorption measured using a WPI ultrapath spectrophotometer.
ag calculated as 2.303*A/r where A is the measured absorbance and r is the
pathlength in meters (2.03 m in this case). ag data are corrected for scattering
using A at 700 nm.

Instrument details:
World Precision Insturments (WPI) UltraPath spectral absorbance system
with 200cm liquid waveguide cell, TIDAS-2 diode array spectrometer and
D2H Deuterium-Halogen light source. See WPI web-page for details.