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General Objective:

The potential for L2P uptake by Mediterranean users : validation, intercomparison and improvements of Medspiration and MFS L4 products and processors. General Objective:

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General Objective:

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  1. The potential for L2P uptake by Mediterranean users: validation, intercomparison and improvements of Medspiration and MFS L4 products and processors General Objective: to improve the quality of SST products used by EU-MERSEA modeling and assimilation centres and produce Mediterranean Sea analyzed SST fields needed for MERSEA models

  2. CNR work within EU-MERSEA project concerns: • Inter-comparison and validation of MEDSPIRATION L4 and MFSTEP SST products. • Tuning of Medspiration L4_processor • Improvement of MFSTEP analyses Ref. MERSEA deliverable: Report on the inter-comparison of MEDSPIRATION and MFSTEP SST analyses over the Mediterranean Sea.

  3. Could Medspiration L4 sub-sampled over MFS grid be used in the assimilation? • Could the present MFS analysis be improved by including Medspiration L2P data? • or: • Can it be run only with Medspiration L2P? • Can the Medspiration L4 software be run directly to interpolate on the model grid, with stable results, possibly improving MFS?

  4. MFS L4 using GHRSST productsf l o w c h a r t MF AVHRR acquisition Atlantic buffer zone + west Med ISAC AVHRR acquisition Entire Mediterranean Night-time SST using MF algorithm Cloud detection Night-time SST using Pathfinder algorithm Cloud detection SST daily composite binning on model grid (1/16x1/16) SST daily composite binning on model grid (1/16x1/16) Data merging ISAC L2P Medspiration Products Data quality controll Optimal Interpolation Data delivery on the GOS-ISAC web-site

  5. Period examined: jan-oct 2005 Methods: Evaluation of processor performance: -qualitative -quantitative Comparison of SST L4 against quality controlled in situ XBT data acquired within MFSTEP Test performed: MFS at 1/16°AVHRR by CNR+CMS merging MFS data and SEVIRI/AATSR L2P only L2P (all infrared) original configuration Medspiration L4 at 2 kmresampled at 1/16° L2P original configuration Medspiration L4 at 1/16° (hereafter MERSEA L4) L2P different configurations starting from parameters similar to MFS ones

  6. REMARKS: • MFS and Medspiration processors have different data editing and selection criteria/strategies -bias between sensors -selection of valid input (confidence values, clouds) -selection of influential observations within the bubble • but the different OI configurations can be tuned to have - similarspatial and temporal influential radius (‘bubble’)… - same correlation function - same grid/resolution

  7. Evaluation of SENSOR BIASESneeded to choose a reference sensor for data merging with MFS processorimpact on quality of MERSEA L4 MFSTEP –spatial distribution of XBT measurements

  8. Evaluation of SENSOR BIASES: results

  9. L =180 km τ =7 days Medspiration results: MFS: Reference sensor priority: AATSR NAR17 AVHRR17_L SEVIRI NAR16 AVHRR16_L DIST=200 starting spatial influential radius for data selection. RMAXDIST=600 maximum spatial influential radius for data selection (the influential radius is incremented if data selected within DIST are less then LIMIT). NPIX=3 number of values selected in time for each pixel. MERSEA: SELMS_LIST > NAR17_SST AVHRR17_L NAR16_SST AVHRR16_L X_BUL_RATIO=2.0 Y_BUL_RATIO=2.0 T_BUL_RATIO=1.0 OAN_KEEP_ALL_MEAS = 0 # For each sensor, in each cell of the collated file, only the nearest # measurement to the processing date is kept. There is only one # observation file created per sensor. # # OAN_KEEP_ALL_MEAS = 1 # For each sensor, in each cell of the collated file, the whole # measurements are kept. There is one observation file per sensor and # per days created.

  10. MFS and Medspiration L4 original configuration MFS (only AVHRR) MEDSPIRATION L4 subsampled at 1/16°

  11. MFS with new INPUT data MFS (MFS+infrared L2P) MFS (infrared L2P only)

  12. MERSEA L4 (CLS processor with new configuration) MERSEA (no bias) MERSEA (bias correction)

  13. MFS and Medspiration L4 original configuration

  14. MFS with new input data

  15. MERSEA L4 (CLS processor with new configuration)

  16. MFS and MERSEA new L4 configuration

  17. MFS and Medspiration L4 original configuration

  18. MFS with new INPUT data

  19. MERSEA L4 (CLS processor with new configuration)

  20. MFS and MERSEA new L4 configuration

  21. No bias correction Impact of bias correction on MERSEA L4 Bias correction applied

  22. Impact of the number of observations per sensor (A2e) bias, OAN_KEEP_ALL_MEAS=0 (A1d) bias, OAN_KEEP_ALL_MEAS=1

  23. One possible evolution # OAN_KEEP_ALL_MEAS = N # For each sensor, in each cell of the collated file, only the first N nearest in time # measurements are kept. There is one observation file per sensor and # per days created???? • other possible evolution: data reduction strategy?

  24. CONCLUSIONS Could Medspiration L4 sub-sampled over MFS grid be used in the assimilation? not with original configuration Could the present MFS analysis be improved by including Medspiration L2P data? Yes, to be implemented operationally Can it be run only with Medspiration L2P? Yes, to be implemented operationally Can the Medspiration L4 software be run to interpolate directly on the model grid, with stable results, possibly improving MFS? Possibly yes, but more work has to be done (understand biases, reduce computation time)

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