A Comparison of Particulate Organic Carbon (POC) from In situ and Satellite Ocean Color Data Off the...
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Transcript of A Comparison of Particulate Organic Carbon (POC) from In situ and Satellite Ocean Color Data Off the...
A Comparison of Particulate Organic Carbon (POC) from In
situ and Satellite Ocean Color Data Off the Coast of
Antarctica
Amanda HydeAntonio Mannino (advisor)
Research and Discover Program; 2010
Importance of satellites
Spatial coverage from scientific cruises over 20 years (Gardner et al. 2006)
Spatial cover from SeaWiFS on July 18, 2010
(http://oceancolor.gsfc.nasa.gov 2010)
versus
Measuring POC from satellites
Sea Surface
Top-of-the-Atmosphere
The satellite views the spectral light field at the top-of-the-atmosphere.
Satellite
POC
1. Removes atmosphere from the total signal to derive estimate of light field emanating from sea surface (water-leaving radiance, Lw).
2. Relates remote-sensing reflectance to geophysical product (POC) of interest.
3. Spatially / temporally bin and remap satellite POC observations.
Orbital path of MODIS (NASA Ocean Biology Processing
Group 2008)
Basics of measuring ocean color from an orbiting satellite (NASA Ocean Biology
Processing Group 2008)
Algorithms
POC = 169.7×[Rrs(443)/Rrs(555)]-0.936
(Stramski et al. 2008)
visible light
wavelength (nm)
near-infraredultra-violet
Rrs(λ) = remote-sensing reflectance (units =
sr-1) NASA Ocean Biology Processing Group 2008
Study site
A. Hyde 2010
www.bugbog.com 2010
Sampling stations off the coast of the
Antarctic Peninsula
N
in the lab...
Elementar vario MICRO cube CHN Elemental Analyzer (A. Hyde 2010)
12M HCl acid fuming to remove inorganic carbon
(A. Hyde 2010)
From filter to tablet (A. Hyde 2010)
Processing satellite data
Level 1A ocean color data (available at oceancolor.gsfc.nasa.gov)
Dates used: Feb 21 - Mar 4, 2008
60S - 65S latitude; 50W - 63W longitude
Seadas 6.1.1 used for processing
http://oceancolor.gsfc.nasa.gov 2010
Results
In situ [POC] ranged from 79.0 ug/L to 232.2 ug/L
Satellite derived [POC] ranged from 69.0 ug/L to 155.2 ug/L
A. Hyde 2010
Example of L2 POC data file of March 4, 2008 (A. Hyde 2010)
Statistics
Mean APD% = 16.4%
RMSE = 30.4 ug/L
Percent differences ranged between 4.1% and 33.2%
No significant difference between in situ and satellite derived POC (JMP 8.0, one-way ANOVA, p > 0.05)
R2 = 0.89slope = 0.52RMSE = 30.4N = 11
need for further satellite validation
SOS cruise lasted 13 days; 2 days of satellite ocean color data were usable
85 stations included; only 11 had correlating satellite ocean color data
Data containing clouds, ice, sun glint, high radiance, stray light, high viewing zenith angle, and high solar zenith angle were all excluded
On average, only 15% of satellite data are usable (Bailey and Werdell 2006)
www.tpwd.state.tx.us 2010
Thanks to...
UNH-NASA Research and Discover Program
Antonio Mannino - advisor
Mike Novak - lab help
Sean Bailey - Seadas 6.1.1 help
www.eos.unh.edu 2010www.nasa.gov 2010
Literature cited
Anon. 2008. “Protocol for vario MICRO cube Elemental Analyzer” handout from A. Mannino. 14 Jun 2010.
Bailey, S. W. and P. J. Werdell. 2006. A multi-sensor approach for the on-orbit validation of ocean color satellite data products. Remote Sensing of Environment 102: 12-23.
Gardner, W. D., A. V. Mishonov, and M. J. Richardson. 2006. Global POC concentrations from in-situ and satellite data. Deep-Sea Research II 53: 718-740.
Mannino, A., M. E. Russ, and S. B. Hooker. 2008. Algorithm development and validation for satellite-derived distributions of DOC and CDOM in the U.S. Middle Atlantic Bight. Journal of Geophysical Reserach 113
Stramski, D., R. A. Reynolds, M. Babin, S. Kaczmarek, M. R., Lewis, R. Röttgers, A. Sciandra, M. Stramska, M. S. Twardowski, B. A. Franz, and H. Claustre. 2008. Relationships between the surface concentration of particulate organic carbon and optical properties in the eastern South Pacific and eastern Atlantic Ocean. Biogeosciences 5: 171-201.
Image CitationsAnon. 2010. Antarctica Circle Map. http://www.bugbog.com/images/maps/antarctic-circle_map.jpg (22 Jul 2010)
Anon. 2010. home page www.nasa.gov (22 Jul 2010)
Anon. 2010. Sunday, 18 Jul 2010 (2010199). http://oceancolor.gsfc.nasa.gov/cgi/pcac9000.pl?day=2010199W (13 Jul 2010)
Anon. 2010. untitled. http://oceancolor.gsfc.nasa.gov/cgi/l3/A20080572008064.L3m_8D_POC_poc_4km.png?sub=img (13 Jul 2010)
Anon. 2010. Research and Discover. http://www.eos.unh.edu/researchanddiscover/interns.shtml (29 Jul 2010)
Fennell, S. 2010. Do you have questions about your online store? #ecommerce. http://blog.1choice4yourstore.com/2010_03_01_archive.html (21 Jul 2010)
Gardner, W. D., A. V. Mishonov, and M. J. Richardson. 2006. Global POC concentrations from in-situ and satellite data. Deep-Sea Research II 53: 718-740.
Hyde, A. 2010. Personal photos.
Loeffler, C. 2004. The state of wonder: what’s all this fuss about water? http://www.tpwd.state.tx.us/learning/webcasts/connections04/water.phtml (23 Jul 2010)
NASA Ocean Biology Processing Group. 2008. Satellite observations of ocean color. SeaDAS Training Material; Goddard Space Flight Center, Greenbelt, Maryland.