Ocean Carbon and Biogeochemistry Data System

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EDDIES cruise: 2004 and 2005 R/V Oceanus Survey cruises
Satlantic light-profiling system processing notes

PI: Dave Siegel (UCSB)

13 November 2007: Prepared for OCB data system by Nancy Copley (Biology Dept, WHOI) and Cyndy Chandler, BCO-DMO (MCG Dept, WHOI).

Methodology
It is important to note that two different light-profiling systems were used for the EDDIES experiment. The Weatherbird II used a Satlantic profiling radiometer system (SPMR/SMSR), which has been a standard operating procedure for BBOP over the past 8 years. The Oceanus used a Satlantic Micro-Profiler II.

R/V OCEANUS Satlantic Micro-Profiler Description
The profiler aboard the Oceanus was a Satlantic Micro-Profiler. Like the SPMR (used during the Weatherbird II cruises), its primary optical measurements are downwelling irradiance (Ed) and upwelling radiance (Lu). However, the Micro-Pro collects measurements in the following wavelengths: 305, 325, 340, 380, 412, 443, 490, 510, 555, 665, and 683. (Note the additional UV channel). The units for each channel are the same (uW/cm2/nm and uW/cm2/nm/sr respectively).

SMSR
The Micro-Pro is accompanied by the same system as Weatherbird although data is later synchronized based on time.

DATA COLLECTION
[ Same as Weatherbird II ] A profile begins after the instrument has been deployed and reaches a distance of approximately 50 meters from the ship's stern (to avoid ship shadow). The instrument is then released and falls at approximately 0.5 m/s and is synchronized with the SMSR on the deck of the ship.

DATA PROCESSING
Data collected from the Micro-Pro is processed with Satlantic ProSoft 7.7.

Like the BBOP method, surface values of the profiler measurements are obtained as the intercept of a least squares regression fit. In cases of shallow depths that do not meet the number of points for regression, the surface variable is calculated based on the intercept of the k slope from the first depth value that does have the required number of points. Derived surface products include remote sensing reflectances (Rrs), down-welled attenuation coefficients (Kd) and up-welled attenuation coefficients (Kl). The units are 1/sr, 1/m and 1/m respectively.

These data are a collection of in-situ measurements gathered from the OCEANUS research vessel during the EDDIES experiment (2004 and 2005) Survey cruises.

 

Contact: David Court (dcourt@icess.ucsb.edu)
              Institute for Computational Earth System Science
              University of California, Santa Barbara (UCSB)