WP2: Data products generation in Mediterranean Sea EMODNET Chemistry Data Products, Experts Workshop Split (Croatia), June 2014 Sissy Iona, HCMR-HNODC

Outline  Regional data processing and QC  Data aggregation  Products generation-Diva Analysis

Regional pool  Current chemical data availability :  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)

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)

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

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

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

Nutrients Data Ammonium, vertical profiles, NO2+NO3, 3821 vertical profiles,

Nutrients Data Nitrate, vertical profiles, Nitrite, vertical profiles,

Nutrients Data Phosphate, vertical profiles, SiO4, vertical profiles,

Some scatter plots  Mediter., PO4  Mean: 0.162±0.254  Min: 0  Max:  total meas.,  Summer: meas  Winter: 31702meas

Some scatter plots  Mediter., PO4  Mean: 0.162±0.254  Min: 0  Max:  total meas.,  Summer: meas  Winter: meas

Some scatter plots  Adriatic, SiO4  Mean: 4.566±6.621  Min: 0  Max:  total meas.,  Summer: 9191 meas  Winter: 6531 meas

Some scatter plots  Adriatic, SiO4  Mean: 4.566±6.621  Min: 0  Max:  total meas.,  Summer: 9191 meas  Winter: 6531 meas

Exclude zeros (~6%) from DIVA analysis ? total meas.zerosDefault flaggedNegatives PO SiO NO NH NO NOx Total Results of QC

 4 MSFD regions in Mediterranean  First results in Adriatic and Western Med  Nitrates, Phosphates, Silicates, NH4 (not shown here) Diva Analysis

Analysis & errors fields  We will mask areas of poor data coverage

Analysis & errors fields  Disregard these areas also?

Other results

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

Mean: Std: Detection of trends Mean summer NO3 at first 10 m, over the area N , E12-15