particulate organic carbon (poc) measured from satellites wilford gardner mary jo richardson young...
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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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