GSM-Med - Observatoire Océanologique de Villefranche sur Mer

Spatial-temporal dynamics of Chromophoric Dissolved Organic Matter (CDOM) and Colored
Detrital Matter (CDM) light absorption coefficients in the Mediterranean Sea:
from in situ data to a SeaWiFS climatology
Emanuele Organellia*, Annick Bricauda, David Antoine ab, Bernard Gentilia, Atsushi Matsuokac, Melek Golbola and Vincenzo Velluccia
a Laboratoire
d’Océanographie de Villefranche, UMR 7093, CNRS and Université Pierre et Marie Curie (Paris 6), 06238 Villefranche sur Mer, FRANCE
b Remote
Sensing and Satellite Research Group, Curtin University, Perth, WA 6845, AUSTRALIA
c Takuvik
Joint International Laboratory, UMI 3376, CNRS and Université Laval, Québec City, Québec, CANADA
*[email protected]
Spatio-temporal variability of CDOM and CDM light absorption coefficients in the Mediterranean Sea is still poorly understood because of a
limited number of field studies and not-validated bio-optical inversion models for Ocean Color applications……………
1. CDOM PATTERNS AND DRIVERS AT THE BOUSSOLE SITE
(NW Mediterranean Sea; see also posters 2015, 2019, 2084 & 2122 for other studies at this site)
acdom(440) (m-1)
CDOM Content
Microbial
(measured with a 2 m path length Ultrapath within 24 h from sampling)
Vertical homogenization in Winter
Subsurface maxima in Spring and Summer
Production!
at 30 m
MLD
CDOM-depleted surface layer in Summer
Scdom (nm-1)
Spectral Slope
Photobleaching!
(computed between 350 and 500 nm by a non-linear least-square fit)
Similar values in 0-200 m during Winter
High values at the surface in Summer and
MLD
2. BIO-OPTICAL RELATIONSHIPS
(for CDOM degradation)
Autumn
r2=0.60
n=34
Low values at the depth of CDOM maxima
(at surface of the BOUSSOLE site)
3. INVERSION MODEL PERFORMANCES
Morel & Gentili 2009
y=1.16x
r2=0.84; n=30
RMSE=50%
(using field Rrs measurements)
GSM
Ciotti &
Bricaud 2006
QAA
y=1.16x
y=0.98x
r2=0.94; n=27
r2=0.94; n=30
RMSE=33%
RMSE=25%
y=0.82x
r2=0.90; n=30
RMSE=32%
r2=0.29
n=34
GSM-Med
A locally-tuned version of the GSM (called “GSM-Med”) is
developed using in situ data collected at BOUSSOLE
acdom(440) for a given chlorophyll concentration is
between 2003 and 2012, and tested over the year 2013.
higher than expected from Case I waters
y=0.90x
r2=0.93; n=9
RMSE=24%
bio-optical models!
4. CDM TIME-SERIES AT BOUSSOLE
(using field and SeaWiFS Rrs data)
 CDM time-series from field Rrs reproduces in situ CDM dynamics (2011-2013)
QAA
acdm(443) values (in m-1) derived from GSM-Med and SeaWiFS imagery (2003-2010)
GSM-Med
 Agreement between CDM time-series from field and SeaWiFS Rrs (2003-2010)
QAA
5. CLIMATOLOGY OF CDM IN THE MEDITERRANEAN SEA
GSM-Med
Winter
Spring
Summer
Autumn
 Similar time-series but GSM-Med generally returns lower CDM values than QAA
You can read more about CDOM and CDM in:
Organelli E., Bricaud A., Antoine D. & A. Matsuoka (2014). Seasonal dynamics of light absorption by Chromophoric Dissolved
Organic Matter (CDOM) in the NW Mediterranean Sea (BOUSSOLE site). Deep-Sea Research I, 91, 72-85.
Acknowledgements
Organelli E., Bricaud A., Gentili B., Antoine D. & V. Vellucci. Evaluation of bio-optical inversion models for the retrieval of Colored
This study is a contribution to the BIOCAREX (funded by ANR) and
Dissolved Organic Matter (CDOM) and Colored Detrital Matter (CDM) light absorption coefficients in the Mediterranean Sea
BOUSSOLE (funded by ESA, NASA, CNES, CNRS, INSU, UPMC, OOV) projects.
using field and satellite ocean color radiometry. Submitted to Remote Sensing of Environment.