New applications with geostationary ocean colour radiometry
Specific research topic:
“Dynamics of suspended particulate matter (SPM)
in river plumes”
David Doxaran, LOV, CNRS-UPMC, France
And colleagues from ACRI-ST, KOSC-KIOST, MUMM, NOAA
International Ocean Colour Science (IOCS) meeting , 6-8 May 2013, Darmstadt, Germany
(Zhang et al. 2010) (Wang et al. 2007)
The Yangtze and Yellow Rivers (China) aer two major world rivers in tems of
freshwater discharge and export of terrestrial substances (e.g., SPM, POC)
Study areas viewed by GOCI
Isobath Red:10m, Yellow:30m, Cyan:50m, Blue:100m, Magenta:200
Ieodo
South
Korea
Ch
ina
• Atmospheric optical depth (36 km)
• Low sun zenith angles (9am and 4pm)
• No SWIR band (GOCI)
SPM algorithm: issues with GEO sensors
Two atmospheric correction algorithms
specific for turbid waters developed for GOCI:
• Ahn et al. (2012): extension of the NIR
similarity spectrum (Ruddick et al. 2006) to
extremely turbid waters
• Wang et al. (2012; 2013): Use of invariant
regional relationships established between
nLw(NIR) and Kd(490) derived from MODIS-
Aqua products generated using the SWIR
atmospheric correction
From Lamquin et al. 2012
Assessment of GOCI seawater reflectance products
Comparing GOCI Rrs products (Ahn et al.
2012) to MODIS-Aqua Rrs (SWIR corrected
(Wang and Shi 2007)
Preliminar ‘validation’ of GOCI Rrs
products in the visible (500 – 700 nm)
Significant differences in the NIR
04/09/2011
RRC MERIS (865)
RR
C G
OC
I (8
65
)
11/04/2011
9h16 (local)
Applications: filter clouds and SPM tidal dynamics
11/04/2011
10h16 (local)
11/04/2011
11h16 (local)
11/04/2011
12h16 (local)
11/04/2011
13h16 (local)
11/04/2011
14h16 (local)
11/04/2011
15h16 (local)
11/04/2011
16h16 (local)
Hangzhou Bay appears (clouds)
Maximum turbidity at low water
Ongoing work…
0,5
1
1,5
2
2,5
8 10 12 14 16
Local tile (h)
Wate
r depth
(m
)
RRC(560) (dl)
12 July 2012
30 Nov. 2012
GEO satellite observations combined with data from autonomous profiling floats (Provbio)
► The capabilities of GEO ocean colour remote sensing
already demonstrated (GOCI)
► New applications:
- in coastal waters: fluxes at land-sea interfaces, tidal
dynamics and residual transport
- in the open ocean: daily cycles of primary production?
► Future missions:
e.g., OCAPI mission
Ocean Color Advanced Permanent Imager
“A breakthrough in ocean sciences thanks to hourly
observations of ocean colour in coastal zones and the
open ocean from a geosynchronous orbit”
First conclusions and perspectives
Provbio profiling float
Use of optical data from autonomous
profiling and drifting floats in the
Gironde and Rhône river plumes: the
PROVPANACHE project (PI D. Doxaran)
Profiling floats: autonomous
physical & optical measurements
PROVBIO : PROVOR + c(660) + bb(555) + Chla
Fluo + CDOM Fluo + Ed(3l) + iridium
PI H. Claustre (LOV)
www.oao.obs-vlfr.fr/carto/index.html
