######  
 
It's 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.  
 
WEATHERBIRD II  
 
SPMR  
The profiler used aboard the Weatherbird II is a SeaWiFS Profiling Multi-Channel 
Radiometer (SPMR).  It is a free-falling instrument that is equipped with two sensors, 
collecting the upwelling irradiance (Ed) and downwelling (Lu) radiance at the following 
11 wavelengths: 324, 340, 380, 412, 443, 490, 510, 555, 565, 665, and 683nm.  
The unit is protected in a long case that contains the majority of the system's electronics, 
while the optical sensors are located at either end of the case and face in opposite 
directions (i.e., up and down). These sensors measure the irradiance in units of 
uW/cm2/nm and the radiance in units of uW/cm2/nm/sr.  Tilt and pressure are recorded at 
the same frequency as the irradiance measurements (6Hz).  
 
SMSR  
The SPMR is accompanied by a deck reference sensor, called the SeaWiFS Multichannel 
Surface Reference (SMSR). This sensor is equipped with the same 11 wavelengths as the 
SPMR, and is based on the same electronics. Data acquisition is synchronized between 
the SPMR and the SMSR and is performed at the same (6Hz) frequency.  
 
CALIBRATION  
The system is calibrated with respect to NIST standards three times a year at UCSB and 
variation from those standards has been less than 2%.  However, most of this variation 
has occurred within the UV and blue channels (as opposed to the red) and is partly due to 
the lower output of calibration lamps at lower wavelengths.  All other changes in 
sensitivity were most likely due to the replacement of the sensors' cosine collectors.  
 
DATA COLLECTION  
An SPMR 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.  
 
PROCESSING  
The Weatherbird radiometric data were processed using a series of standardized BBOP 
processing scripts written by research members at ICESS.  This system creates a quality 
controlled and quality assessed 1m binned data set.  
The irradiance values at "just below the surface" or "(0-)" are obtained as the intercept of 
a least squares regression fit of each profile.  The calculated intercept is a product of the 
diffuse attenuation coefficient (Kd) calculation.  As a result, if the optical properties are 
propagated to the surface, the Kd profile for each optical variable (Ed, Lu) will be 
calculated as well.  
 
i.e. Kd = -dlnEd(ed,lu,etc)/d(z)  
 
while the intercept is determined by: lnEd(0-) = lnEd(z)+Kd(z)  
 
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.  
 
Rrs is calculated as the ratio of the upwelling irradiance just below the surface (0-) to 
downwelling radiance just below the surface (0-).  The "above surface" (or "0+") values 
are derived by simply multiplying a constant of 0.5238.  
 
The attenuation coefficients (Kd & Kl) for the surface were derived by calculating the 
average of the top 25 meters of the profiles.  
 
Suspicious data values (i.e. low signals or "spiking") were corrected (or "flagged") so that 
users of the data set could determine their usefulness for their own applications.  
 
 
OCEANUS:  
 
Micro-Profiler  
The profiler aboard the Oceanus was a Satlantic Micro-Profiler.  Like the SPMR, 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  
 
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.