EDMODnet Chemistry - DIVA Products from the Baltic Region Örjan Bäck, Lotta Fyrberg, Martin Hansson, Magnus Wenzer Swedish Meteorological and Hydrological Institute - SMHI

The Baltic Sea region

Aggregations of parameters  Parameters: Tot-N, NO3-N (when NO2-N present), NOX-N, NH4-N, Silicate, Tot-P, PO4-P,Chlorophyll-a, Oxygen, pH  208 parameters (data are missing, see. Conclusions)  profiles in total (prior to QC)  profiles from 1990 and onward (prior to QC)

Distribution of ODV-files

ODV Quality control of dataset  Visual and manual quality control  Range  Spikes  Position  Ratio  Need a common standard or guideline (which is about to be developed)

DIVA product setup (first run…) Analysis parameters and options  Year list: 1990 – 2012  Month list: January-February, July-August (Monthly will be tested…)  Var list: Tot-N, NO3-N (when NO2-N present), NOX-N, NH4-N, Silicate, Tot-P, PO4-P,Chlorophyll-a, Oxygen, pH  Countour depth: 0, 20, 50, 100 meters (HELCOM standard depth will be tested…)  Qf list: 1,0,(7) (ODV QF-scheme) Param.par Ispec (error output) : 101, clever poor man’s error estimate, gridded error field. Ireg (background field): 1, data mean subtracted

Driver setup (summary of individual DIVA runs) Data extraction: 1 do it, 0 do nothing, -1 press coord, -10 pressure+Saunders 1 boundary lines and coastlines generation: 0 nothing, 1: contours, 2: UV, 3: cleaning data on mesh: 1, 2: RL, 3: both, 4: 1 + outliers elimination, 5: =4+2 5(cleaning data on mesh + outliers elimination + generation of relative length fields) minimal number of data in a layer. If less, uses data from any month. 0 Parameters estimation and vertical filtering: -3 (correlation length and SN ratio parameters are to be estimated and vertically filtered) Minimal L 0.1 Maximal L 3 Minimal SN 0.1 Maximal SN 20 Analysis and reference field: 1 (analysis fields of the given variable are to be performed for all the layers) lowerlevel number 1 upperlevel number 4 4D netcdf files genaration: 1 gnuplot plots: 0 or 1 0 Data detrending: number of groups, 0 if no detrending. 1 (remove any trends in the data before analysis)

DIVA product examples (first run…)  Masked with error field of 0.2  Plots generated in Diva python tool

NOx-N, 0m

NO3-N (when NO2-N present), 0m

NO3-N (when NO2-N present)

NH4-N, 50m

NH4-N, 100m

Tot-N, 0m

Error field: Tot-N, 0m why??

PO4-P, 0m

SiO3-Si,

Error field: SiO3-Si, 0m why??

Oxygen, 50m

pH  The results for pH ranged far from expected values.  We found that that the pH had been analyzed as phosphate.  In DIVA var list: Aggregated_pH is the same as Aggregated_Phosphate  Unfortunately, there were no time for re-run of DIVA.

Conclusion of first run (data set quality and preprocessing problems)  Provided data Profiles with no “Depth”-variable:  Only “Min depth” and “Max depth”  Chlorophyll a: point average Profiles with mismatching semantic header and header Profiles with position (0,0) Control system for those kinds of errors? Some data with bad prior QC (also CDI-link not working: “We are sorry, but the requested CDI data set reference can not be found at present. Activities are on-going for correcting this issue.” ) Request the whole data set again???

Conclusion of first run (data set quality and preprocessing problems)  Mapping and ODV: Problems with confusing parameter codes in P01 and P02. For example NTOT (P02) is PON (led to incorrect aggregation) Parameter is not imported into ODV (NTOT). Seems to be working better with newest ODV-version (alpha version 6.4.3) provided by Reiner Schlitzer. Change of flag scheme when aggregating. Might have lost information/ profiles (flag 6)

Conclusion of first run (DIVA)  DIVA product generation: A protocol is needed to set the options and setting that should be general for all regions.  The should be a discussion about options and setting that must be region specific.  Use Jan-Feb, Mars-May, June-August, Sept-Okt, Nov-Dec. ok? To avoid mixing data before and after spring/autumn bloom, etc.  Be aware: In DIVA var list Aggregated_pH is the same as Aggregated_Phosphate  Diva products for NOX-N, NH4-N, PO4-P, Tot-P, Oxygen are OK  More work is needed for Tot-N, SiO3-Si, pH, Chlorophyll-a, NO3-N (when NO2-N is present)