Particulate Organic Carbon
(POC) measured from satellites
Wilford Gardner
Mary Jo Richardson
Young Baek Son
Alexey Mishonov
Texas A&M University
Fulbright Fellow - Greece
OCTET working group report
Particle concentration versus depth
Biogenic particles
dominate
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Chlorophyll content from ocean color
Related to phytoplankton biomass
Refined over the last 30 years
Models to determine primary production
Methods to determine phytoplankton types
Our goal: Determine Particulate Organic Carbon
(POC) from ocean color
Why? Bulk Chl ranges from 0.1 to 2% of POC
Chl is about 1.5 - 4 % of phyto biomass
POC is about 50% of biomass
Increase spatial and temporal resolution
of carbon dynamics in ocean
Monitor past and predict future impacts
of climate change on carbon budget
Study hydrography of NE Gulf of Mexico
9 cruises over 3 years, 60 POC stations per cruise
POC concentration versus
beam attenuation
POC/PM > or < 25%
POC (mg m-3) distribution contoured from surface bottle data
Previous efforts to
estimate POC from
satellite data
Stramski et al, 1999
POC versus Chl
POC versus K490
POC versus Lwn555-not shown
Upwelled irradiance versus POC
at 6 wavelengths
Upwelled irradiance at 6 wavelengths,
binned concentrations 20 - >550 mg m-3
Bars show depths at
which only 1% of the light
energy remains
Garrison Fig. 6.12b
Upwelled irradiance at 6 wavelengths,
binned concentrations 20 - >550 mg m-3
L (555) L (443)
wn
NDCI _ Lwn   wn

Lwn (555) Lwn (443)
Normalized Difference Carbon Index
3rdorder polynomial fit of data
(1.08NDCI _ Lwn3 1.09NDCI _ Lwn 2 1.37NDCI _ Lwn 2.26)
POC  10
Upwelled irradiance at 6 wavelengths,
binned concentrations 20 - >550 mg m-3
L (555) max( L (412),L (443),L (490))
wn
wn
wn
MNDCI _ Lwn   wn


Lwn (555) max( Lwn (412),Lwn (443),Lwn (490))

Maximum Normalized Difference Carbon Index
5th order polynomial fit of data
POC  10(4.36MNDCI _ Lwn 1.77MNDCI _ Lwn
5
4
1.98MNDCI _ Lwn3 0.21MNDCI _ Lwn 2 1.78MNDCI _ Lwn 2.45)
POC from bottles
July 2000
POC from MNDCI
POC from bottles
April 2000
POC from MNDCI
[Pg C] or Pg C/yr
Sabine et al., 2004 SCOPE 62
HCMR PM and POC data - testing algorithms
Conclusions
Shipboard sampling is insufficient - obviously
Algorithm development of upper ocean parameters is needed
Allows global measurements
Beyond physical and political reality with ships
POC can be well correlated with ocean color
Greater spatial & temporal resolution
Can guide sampling strategies
Test for impacts of climate change - need time series
Necessary for ocean modeling - predict future impacts
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