Dataset: Biofloat_48 Hyperspectral Upwelling Plane Radiance - Lu - Profiles
Deployment: Biofloat_48

In situ hyperspectral downwelling plane irradiance Ed(λ) and hyperspectral upwelling radiance Lu(λ) , parameter names Ed and Lu, respectively): The TriOS ACC Ed sensor measured hyperspectral downwelling plane irradiance from 320-950 nm.  The TriOS ARC Lu sensor measured upwelling radiance from 320-950 nm.  Both sensors sampled at ~3.3 nm spectral resolution and 0.3 nm spectral accuracy.  From the raw 12 bit digital values, calibrated irradiance Ed(λ) (W m-2 nm-1) and radiance Lu(λ) (W m-2 sr-1nm-1) was computed from the ACC and ARC sensors, respectively, using pre-cruise factory calibration coefficients and the equations provided by TriOS (TriOS 2004).  ACC Ed and ARC Lu sensor measurement wavelengths are not identical; no spectral interpolation has been performed.  Two data quality parameters are available:  tilt and qflag.  The parameter “tilt” indicates the tilt of the sensor (and float) in degrees from vertical, while qflag indicates data quality: 1 = acceptable, 0 = biofouling suspect. The ACC Ed sensor appears to be biofouled during days 120 – 142; while no biofouling correction has been applied to the radiometric data, qflag is set to zero during this time.  Shading of the ACC (Ed(λ)) by the top-mounted  CTD, GPS and Argos antennas, ring supports is possible; effects of this shading have not been quantified but will appear as variability in the measurements rather than bias.  The effects of self-shading due to the 1 m square drogue deployed during drift mode have not yet been quantified.  For more details, see Radiometry_and_PAR_Calibration-NAB08.pdf.