Pr

1
Gilbert Barrot, Julien Demaria ACRI-ST
2
1 The GlobColour products
What are the GlobColour parameters ? FPS, DDS and
DDS_insitu products Grids and files format
2 Processing status
Which products are currently available ?
3 Data access
Where and how to get the data ?
3
The GlobColour Parameters
Parameters and merging methods
Not all parameters are available for all
merging methods
Methods selected at WS1 Weighted average GSM for
CHL1
All products include error bars and flags
4
The GlobColour Parameters
CHL1 weighted average pre-processing
Inverse formulation is available in the Product
User Guide
5
The GlobColour Parameters
2002/07 CDM_GSM monthly mean
2003/05 CDM_MERIS monthly mean
CDM is the coloured dissolved and detrital
organic materials (m-1). Two GlobColour products
are generated for FPS A merged CDM
concentration is generated using the GSM model
from the daily L3 radiance products of the 3
instruments if available. The other one comes
from the MERIS products.
MERIS-derived CDM product GSM-derived CDM product
6
The GlobColour Parameters
2003/05
2003/05
GSM-derived bbp product
bbp is the particulate back-scattering
coefficient (in m-1) at ?0 443nm. The merged
bbp concentration is generated using the GSM
model. From the initial GlobColour bbp merged
product, we have therefore the possibility of
generating the following products bp (m-1)
bbp/0.015 TSM (g.m-3) 1.73bp
1.73bbp/0.015
7
The GlobColour Parameters
(Morel, 2006)
8
The GlobColour Parameters
Lxxx is the fully normalised water leaving
radiances at xxx nm (in mW/cm²/µm/sr). Spectral
values are 412, 443, 490, 510, 531, 550-565,
620, 665-670, 681 and 709 nm. MERIS reflectances
(L2 products) are converted into fully normalised
water leaving radiances (normalisation is not
applied to the MERIS 681 nm fluorescence band
and to the 709 nm band.).
MODIS-only - MERIS-only - Preprocessing
9
The GlobColour Parameters
The 550-565 bands are submitted to a specific
processing just before averaging to prepare a
more consistent merging between the
instruments. First of all, all bands are
spectrally re-affected to 555 nm, using
inter-spectral conversion rules, which are
functions of the CHL1 concentration.
10
The GlobColour Parameters
EL555 is the relative () excess of radiance at
555 nm, above a given threshold. The EL555
parameter is computed from the L555 fully
normalised water leaving radiance and the CHL1
products. The daily products are computed for
each instrument using the associated daily water
leaving radiance and daily CHL1, while the merged
product is computed from the merged L555 and the
merged CHL1 concentration.
Details in User Guide
11
The GlobColour Parameters
CF July 2002
Takes into account clouds, ice and high aerosol
load contamination
CF is the cloud fraction (expressed in
). daily products percentage of input pixels
per bin flagged as cloudy in the original L2
products 8-days and monthly products percentage
of merged days per bin where the daily
cloud fraction is greater than a specified
threshold (50 in current processor conf.)
12
The GlobColour Parameters
The flags
13
The GlobColour Parameters
Complete details are available in the
GlobColour Product User Guide
Information stored in the products
(1) stdev is not computed in the nearest
neighbour interpolation process (2) before
merging step, error is not provided pixel-wise,
but the global relative error () coming from the
characterisation is saved in metadata (3) stdev
is not defined at the output of the merging
module. Only error is estimated. (4) error is
the output of the weighted average merging model.
Only products merged using this method contain
the error pixel-wise field other products does
not contain this field. (5) for merged daily,
8-days and monthly products, count is not the
number of L2 binned pixels, but the number of
days contributing to the bin. So for merged daily
products, it is always set to 1. (6) computed
from the quadratic sum of the inverse errors of
the parents products. (7) quicklook product does
not contain any geophysical variable
14
FPS, DDS and DDS_insitu
FPS, DDS and DDS_insitu
FPS global products one parameter per file
DDS local products on specific areas (100x100
km2) all parameters in a single file systematic
production
DDS_insitu local products on specific areas all
parameters in a single file production linked to
in-situ data availability
15
Grids and Files Format
GlobColour products are netCDF files
CDL representation in the PUG
16
Grids and Files Format
GlobColour grids
Plate-Carré Integerised Sinusoidal
1 km 0.25 1.00 4.6 km
All bins Only valid bins
Easy geolocation More complex
17
Grids and Files Format

• The row(), col(), center_lat(), center_lon() and
  lon_step() arrays allow an easier conversion of
  the bin index into geographical coordinates.
• Equations to compute center longitude and
  latitude for a bin b
• index row(b) first_row (first_row is
  a global attribute)
• lat(b) center_lat( index )
• lon(b) center_lon( index ) col(b)
  lon_step( index )

18
Grids and Files Format
Tools to browse/plot ISIN and PC products are
available on the GlobColour web site
and any external tools using netCDF reader and
ISIN / PC grid definition
19
1 The GlobColour products
What are the GlobColour parameters ? FPS, DDS and
DDS_insitu products Grids and file formats
2 Processing status
Which products are currently available ?
3 Data access
Where and how to get the data ?
20
Processing Status
21
Processing Status
22
Processing Status
L3b 68491 1/24
L3m 136982 0.25 1.00
png 68491 0.25
fps
L3m TR 99934 1 km
L3b TR 101541 1/24
L3b DAY 280028 1/24
dds
L3m TR 6691 1 km
L3b TR 6769 1/24
L3b DAY 16229 1/24
dds_insitu
23
Processing Status
FPS 1.0
MERIS data 04/2002 end 2006
MODIS data 06/2002 end 2006
SeaWiFS data 09/1997 end 2002
Merged products 3 instruments only for 2002
24
Processing Status
FPS 1.1
MERIS data 04/2002 end 2006
MODIS data 06/2002 end 2006
SeaWiFS data 09/1997 end 2006
Extention to end 2006 on distribution
servers before Xmas
25
Processing Status
FPS 2.0
MERIS data 04/2002 end 2007
MODIS data 06/2002 end 2007
SeaWiFS data 09/1997 end 2007
Available in 2008
Start of NRT service demonstration
26
1 The GlobColour products
What are the GlobColour parameters ? FPS, DDS and
DDS_insitu products Grids and file formats
2 Processing status
Which products are currently available ?
3 Data access
Where and how to get the data ?
27
Data Access
Data Access
ftp web ()
All products All products
Tree structure Selection (GUI)
No extraction Extraction
GlobColour web site Available early 2008
28
Data Access
ftp data access 2 ways at least
29
Thank you for your attention