Particulate Organic Carbon (POC) measured from satellites

Wilford GardnerMary Jo RichardsonYoung Baek SonAlexey Mishonov

Texas A&M University

Fulbright Fellow - Greece

OCTET working group report

Particle concentration versus depth

Biogenic particles dominate

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Chlorophyll content from ocean colorChlorophyll content from ocean colorRelated to phytoplankton biomassRefined over the last 30 yearsModels to determine primary productionMethods to determine phytoplankton types

Our goal: Determine Particulate Organic Carbon(POC) from ocean color

Why? Bulk Chl ranges from 0.1 to 2% of POCChl is about 1.5 - 4 % of phyto biomass POC is about 50% of biomass Increase spatial and temporal resolution

of carbon dynamics in oceanMonitor 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

POC versus Chl

POC versus K490

Previous efforts to estimate POC from satellite data Stramski et al, 1999

POC versus Lwn555-not shown

Upwelled irradiance versus POC at 6 wavelengths

Upwelled irradiance at 6 wavelengths, binned concentrations 20 - >550 mg m-3

Garrison Fig. 6.12b

Bars show depths at which only 1% of the light energy remains

Upwelled irradiance at 6 wavelengths, binned concentrations 20 - >550 mg m-3

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NDCI _Lwn =Lwn(555)− Lwn(443)( )

Lwn(555)+ Lwn(443)( )

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POC = 10(1.08×NDCI _ Lwn3+1.09×NDCI _ Lwn2+1.37×NDCI _ Lwn+ 2.26)

3rd order polynomial fit of data

Normalized Difference Carbon Index

Upwelled irradiance at 6 wavelengths, binned concentrations 20 - >550 mg m-3

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MNDCI _Lwn =Lwn(555)− max(Lwn(412),Lwn(443),Lwn(490)){ }

Lwn(555)+ max(Lwn(412),Lwn(443),Lwn(490)){ }

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POC = 10(4.36×MNDCI _ Lwn5+1.77×MNDCI _ Lwn4 −1.98×MNDCI _ Lwn3 −0.21×MNDCI _ Lwn2+1.78×MNDCI _ Lwn+ 2.45)

5th order polynomial fit of data

Maximum Normalized Difference Carbon Index

POC from bottles

POC from MNDCI

July 2000

POC from bottles

POC from MNDCI

April 2000

[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 measurementsBeyond 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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