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WP2: Data products generation in Mediterranean Sea EMODNET Chemistry Data Products, Experts Workshop Split (Croatia), 17-18 June 2014 Sissy Iona, HCMR-HNODC
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Outline Regional data processing and QC Data aggregation Products generation-Diva Analysis
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Regional pool Current chemical data availability : 29.583 stations (of vertical profiles and time series) 231 parameters 25 Organizations/NODCs from 12 countries An example below of grouping of phosphate data (different methods, instruments, names, usage codes, units)
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Data processing – QA/QC (1/2) Use of Ocean Data View tool We keep only the “good” originator’s data and apply additional QC checks Create Individual collections for each initial parameter: 1. Perform QC (e.g. scatter plots and range checks) 2. Remaining errors flagged from “good” to “bad” (e.g. negative values, default values, etc) 3. Derived parameters prepared -for conversion to preferred products units (after step 1,2) 4. Each initial parameter and derives exported in separate ODV spreadsheets (export only “good “ data)
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Data processing – QA/QC (2/2) Reports of QC flag changes & format corrections were kept and sent to data originators/providers No duplicates checks (was done before from SDN/MyOcean) Units conversion: PHOS/NO2/NO2+NO3/NO3/NH4 in µg/l converted in µmol/l by division by the atomic weight of phosphorus/nitrogen (most likely be µg N/l) SiO4 data in µg/l converted using the molecular weight of the compound (from collocated comparisons) µmol/kg converted to µmol/l automatically by ODV
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Data aggregation The good & clean data of previous step 4 are finally merged at the first 5 priority data products: NH4, NO2, NO3, NOX (NO2+NO3), PO4, SiO4 in the preferred unit [µmol/l] 4 digits SeaDataNet QC flag scale
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QC of aggregated data QC of previous steps (1,2) are repeated for any remaining errors Information related with the data origin (e.g. LOCAL_CDI_ID and EDMO ) kept in the final aggregated data sets for further contact with the originators if necessary during the next stages of the analysis
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Nutrients Data Ammonium, 12706 vertical profiles, 1970 - 2013 NO2+NO3, 3821 vertical profiles, 1979 - 2012
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Nutrients Data Nitrate, 20246 vertical profiles, 1961 - 2013 Nitrite, 20820 vertical profiles, 1961 - 2013
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Nutrients Data Phosphate, 23535 vertical profiles, 1952 - 2013 SiO4, 19892 vertical profiles, 1957 - 2013
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Some scatter plots Mediter., PO4 Mean: 0.162±0.254 Min: 0 Max: 17.013 130566 total meas., Summer: 45632 meas Winter: 31702meas
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Some scatter plots Mediter., PO4 Mean: 0.162±0.254 Min: 0 Max: 17.013 130566 total meas., Summer: 45632 meas Winter: 31702 meas
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Some scatter plots Adriatic, SiO4 Mean: 4.566±6.621 Min: 0 Max: 361.01 29691 total meas., Summer: 9191 meas Winter: 6531 meas
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Some scatter plots Adriatic, SiO4 Mean: 4.566±6.621 Min: 0 Max: 361.01 29691 total meas., Summer: 9191 meas Winter: 6531 meas
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Exclude zeros (~6%) from DIVA analysis ? total meas.zerosDefault flaggedNegatives PO41236677933123317 SiO411909113745 NO3117006101144044 NH4487042600766 NO2334505166346 NOx2016480 Total46208227187954407 Results of QC
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4 MSFD regions in Mediterranean First results in Adriatic and Western Med Nitrates, Phosphates, Silicates, NH4 (not shown here) Diva Analysis
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Analysis & errors fields We will mask areas of poor data coverage
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Analysis & errors fields Disregard these areas also?
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Other results
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Detection of trends 10 years moving windows (or other time frame) to reveal long term variabilities Centered in the middle of the decade 1970 until 1979 as 1975 1971 until 1980 as 1976 …. Seasonal Analysis January to March as winter April to June as spring …. Reference field Climatic seasonal from all available years (with detrending for removal of uneven spatial distribution in time) Without detrending
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Mean: 0.6000 Std: 0.0736 Detection of trends Mean summer NO3 at first 10 m, over the area N43.5-46, E12-15
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