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The generation and development of the long term Mediterranean SSR products. The aims are: to identify and develop of an optimal algorithm for the Mediterranean sea to produce high quality ocean color datasets for the region.
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The generation and development of the long term Mediterranean SSR products • The aims are: • to identify and develop of an optimal algorithm for the Mediterranean sea to produce high quality ocean color datasets for the region. • to provide an accurate and consistent stream of ocean colour data at a resolution and format compatible with operational forecasting of the Marine Environment. A new regional algorithm for Chlorophyll retrieval The SeaWiFS reanalysis from 1997 to 2004
Bio-optical stations Mediterranean Ocean Color CAL/VAL DATA SETS 10 Mediterranean cruises: from 1998 up to now were organized by ISAC in the framework of Italian National Projects Bio-optical measurements: (143 chl/opt measurement points) to define the Mediterranean regional algorithm In situ chlorophyll-a data: (944 chl profiles) to validate SeaWiFS, Polder, MODIS, MERIS chlorophyll products and merged level 3 binned dataproduced by Mersea
THE NEW MEDITERRANEAN ALGORITHM MEDOC4 : R is log10 of either the 443/560 or the 490/555 or the 510/555 band reflectance ratios. The switch from one band ratio to another one is based on the chlorophyll concentration itself (the Maximum is Chosen)
SeaBAM N=1174 Mediterranean N=137 Optical characteristics:Mediterranean vs Global • Low Chlorophyll: Med Band Ration < Global Band Ratio • Max Ratio choice similar for Med and Global • Is the Med Sea Greener or less Blue then the Global Ocean?
Is the Med Sea Greener or less Blue then the Global Ocean? Chl < 0.1 : -blue (30%); +Green (15%) Chl >0.3 : Med and Global tend to converge 0.1<Chl < 0.3 :+blue (12%); +Green (10%); Global generally use 443 for ratio – Med use 443 50% of the cases 490 50%.
Mediterranean Algorithm Validation Satellite-in situ match-up stations
Conclusions • The analysis confirms that OC4v4 presents a remarkably bias in the oligotrophic chlorophyll range (>100%). • The two regional algorithms (BRIC and DORMA) behave generally better the global OC4v4. • A new Mediterranean algorithm (MedOC4) was developed. The algorithm has and percent MBE around zero in the entire range of Mediterranean conditions. • The validation of the SeaWiFS products demonstrate the improvement obtained in SeaWiFS chlorophyll retrieval when the new MedOC4 is used in the processing chain. The SeaWiFS MedOC4 error is always less the 20% for chlorophyll values > 0.05 mg m-3
The SeaWiFS reanalysis from 1997 to 2004: reprocessing of the entire Mediterranean Sea L1A archive using MedOC4 Algorithm
Input Data • SeaWiFS L1A data from HROM • Add other station: HSPZ, HDUN,…. • Add M_LAC for missing • Total number of pass L1A data 6127 pass
taua_412taua_443taua_490taua_510taua_555taua_670taua_765taua_865taua_412taua_443taua_490taua_510taua_555taua_670taua_765taua_865 Rrs_412Rrs_443Rrs_490Rrs_510Rrs_555Rrs_670Rrs_765Rrs_865 chlor_al2_flagschl_medoc4K_490parsenz The DATA PROCESSING For SeaWiFS one day passes over the Mediterranean Sea Mapped products Top of Atmosphere Reflectances Atmospherically corrected products L2bin … … … L2bin Mosaicked and Merged Passes over the Mediterranean Sea L3bin 2km L1A … … … L1A L2 … … … L2 2km n-L3 … … … n-L3 1km 1km 22 L3 products for each L2 file 1km
WHY GRID? It is an innovative solution for the data access and exchange Increased exploitation of available resources It enables new classes of large-scale, high-power applications (e.s. reprocessing of large data volumes) It is a model for future European EO Ground Segment… It enables interconnection between science computing centers It enables International cooperation in EO applications It enables the production of EO multi sensor merged products for data assimilation
WN:Node01.. ….Node16 DATA PROCESSING ON GRID 1) Globus-job-submit UI CE 2) Globus-job-status Gridtest03.esrin.esa.int Grid0007.esrin.esa.int 3) Globus-job-get-output Globus-url-copy Globus-url-copy SE UI=User Interface SE=Storage element CE=Computer Element WN=Worker node Se0.artov.rm.cnr.it
The processing cost SeaWiFS dataset from 1997 to 2004 ESA-CNR GRID infrastructure GOS infrastructure N° pass= 6127 WN CPU time/pass= 14 min N° WN =16 Total processing time ~ 4 days N° pass= 6127 CPU time/pass= 15 min Total processing time ~ 64 days - 93 % Disc space exploitation Input Data: 164 GB on SE for the whole L1A dataset Output Data: 320 GB on SE for the whole L3 datasets
The GRID products output Previous algorithm NEW algorithm Difference OLD-NEW 2 July 2004 0.01 5 0.01 5 0 -0.1 0.2 OC4.V4 Med OC4 (OC4.V4) – (Med OC4)
NEW algorithm Previous algorithm Difference OLD-NEW 21 April 2004 5 0.01 5 0.01 0 0.3 -0.80 (OC4.V4) – (Med OC4) OC4.V4 Med OC4
1999 Monthly maps OC4.V4 Med OC4 APRIL (OC4.V4) – (Med OC4)
1999 Monthly maps OC4.V4 Med OC4 JULY (OC4.V4) – (Med OC4)
1999 yearly average OC4.V4 Med OC4 (OC4.V4) – (Med OC4)
A regional approachfor the Mediterranean SeaPrimary Production
Introduction WEST MED: 197 gC m-2 y-1 Antoine et al.,1995 EST MED: 137 gC m-2 y-1 Satellite WEST MED: 155-172 gC m-2 y-1 Bosc et al.,2004 EST MED: 114-125 gC m-2 y-1 Other WEST MED: 78-158 gC m-2 y-1 Published values EST MED: 55-97 gC m-2 y-1
Introduction Ze Ctot Ctot Csat Depth (m) Depth (m) Chlorophyll (mg m-3) Chlorophyll (mg m-3) d= day length Ze= euphotic depth PAR(Ze)=1% PAR(0) PUR= f(PAR,Ts) From global in situ profiles Zpd Csat Ze Trophic states
Model adjustments PP Model Adjustment to Mediterranean Conditions • Develop a regional algorithm for satellite chlorophyll retrieval (DORMA, MED_OC4) • Develop new relation for the euphotic depth (Ze) as function of Ctot (total chlorophyll within the euphotic layer) • Develop a new relation between Ctot and Csat • Define the new trophic states for the Mediterranean Sea
Model adjustments Ze Ctot
Model adjustments This study Ctot=45.03 Csat0.595 Morel and Berthon (1989) Ctot=40.6 Csat0.459 Ctot Csat
Model adjustments This study Morel and Berthon (1989) Ranges of Morel and Berthon: 0-0.05, 0.05-0.15, 0.15-0.3,0.3-0.45, 0.45-1.5, 1.5-5, >5 mg m-3
7-14 April 2001 7-14 April 2001 7-14 April 2001 AVHRR OISST from 1998 to 2004 MED_OC4 SeaWiFS Chlorophyll from 1998 to 2004 INPUT DATA New Ranges: 0-0.05, 0.05-0.1, 0.1-0.15, 0.15-0.4, 0.4-1.5, 1.5-5 SeaWiFS PAR from 1998 to 2004
Model Intecomparison Comparison Bosc et al. (2004) April ‘99 December ‘99
Impact of chl algorithm on PP MedOC4 Bricaud OC4 Weekly mean of Mediterranean basin PP
WEST MED: 197 gC m-2 y-1 Antoine et al.,1995 EST MED: 137 gC m-2 y-1 Satellite WEST MED: 155-172 gC m-2 y-1 Bosc et al.,2004 EST MED: 114-125 gC m-2 y-1 Other WEST MED: 102-125 gC m-2 y-1 WEST MED: 78-158 gC m-2 y-1 This Work Published values EST MED: 79-86 gC m-2 y-1 EST MED: 55-97 gC m-2 y-1 our