# Particulate Organic Carbon (POC)

## 1 - Product Summary

This algorithm returns the concentration of particulate organic carbon (POC) in mg m-3, calculated using an empirical relationship derived from in situ measurements of POC and blue-to-green band ratios of remote sensing reflectances (Rrs).

Support for this algorithm is contingent on the availability of bands centered at 443  in the blue region and between 547 and 565 nm in the green region. This implies support for CZCS, OCTS, MODIS-Aqua and Terra, MERIS, SeaWiFS, VIIRS.

Algorithm Point of Contact: Dariusz Stramski, Scripps Institute of Oceanography, and Bryan Franz, NASA Goddard Space Flight Center.

## 2 - Algorithm Description

The algorithm is a power law applied to a blue-to-green band ratio.

##### Inputs:
• $R_{rs}$(443)
• $R_{rs}$ between 547 and 565 nm
##### Output:
• poc, concentration of particulate organic carbon in mg m-3
##### General Algorithm:

The algorithm is a power-law relationship between a ratio of $R_{rs}$ and POC:

$poc = a\times \left(\frac{Rrs(443)}{Rrs(555)}\right)^b$

where

• $a = 203.2$
• $b = -1.034$

In cases where Rrs(555) is not available an equivalence is estimated from the closest native green wavelength using the empirical relationships described in convert_band.c . The input wavelengths used for the various sensors are shown in the table below.

 SeaWiFS 443, 555 MODIS 443, 547 MERIS 443, 560 VIIRS 443, 551

## 3 - Implementation

 Product Short Name poc Level-2 Product Suite OC Level-3 Product Suite POC Level-3 Masking ATMFAIL,LAND,HISATZEN,STRAYLIGHT,CLDICE,LOWLW,NAVWARN,ATMWARN, HISOLZEN,NAVFAIL,FILTER,HIGLINT

For further details on the implementation in the NASA ocean color processing code, see the algorithm source code  and the dependency graph.

## 4 - Assessment

Satellite-to-in-situ validation results are available from the SeaWiFS Bio-Optical Archive and Storage System (SeaBASS) for the following missions:

## 5 - References

Stramski, D., Reynolds, R. A., Babin, M., Kaczmarek, S., Lewis, M. R., Röttgers, R., … Claustre, H. (2008). Relationships between the surface concentration of particulate organic carbon and optical properties in the eastern South Pacific and eastern Atlantic Oceans. Biogeosciences, 5(1), 171-201. doi:10.5194/bg-5-171-2008