Annual Meeting, June 15-16 2015, Istanbul, Turkey

WP2: Results and criticalities in the North

Sea

EMODnet Chemistry

Regional leader: Aarhus University, AU-DCE

Martin M. Larsen, DIVA by Jonas Kofoed Rømer

Annual Meeting, June 15-16 2015, Istanbul, Turkey

Data contibuters:

Current status

EDMO CODE NOx PO4 SiO

28 (CEFAS) 990 988 985

32 (The Environment Agency (EA)) 48 17 53

43 (BODC) 235241 283762 218896

486 (IFREMER) 838 948 956

545 (SMHI) 19377 23959 16041

612 (Norwegian Marine datacenter)8605 8605 8604

681 (RIHMI-WDC)103 503 127

729 (AU-DCE) 62762 62973 50141

1503 (was iFBM, Hamburg uni.)80 80 0

1578 (was MUMM-BMDC)2135 2043 2078

1725 (FMI)14 14 14

2135 (Marine Scotland institute)7264 7269 6667

Annual Meeting, June 15-16 2015, Istanbul, Turkey

General overview of the data contribution:

Current status

NOx PO4 SiO

Total CDI’s (CTD+Nutrients) 640531 640531 640531

Individual nutrients 346555 400535 309421

All nutrients available 263916 263916 263916

Spatial distribution:

- No data from Baltic- Area restricted to“central North Sea”- NOx=NO2+3 or

NO3+NO2 or NO3

Annual Meeting, June 15-16 2015, Istanbul, Turkey

The worst case dataset

SiO dataset

Annual Meeting, June 15-16 2015, Istanbul, Turkey

DIVA production:Topography problems

• Gebco 2014 30 arc-seconds bathymetry used for contours (raises The Netherlands to +1 instead of underwater)

• Too finescaled, so only every 6th grid used

Depths used: 500, 100, 75, 50, 25, 20, 10, 5, 1 and 0.

4 Seasons: Winter 1101, spring 0204, summer 0507, autumn 0810.

46 Decades: one-year interval 1960 – 2006 (+10 years)

Interpolation settings: CL=0.7, SNR= 1.0 Ref. field CL=3, SNR=0.1

Annual Meeting, June 15-16 2015, Istanbul, Turkey

NOx Vinter-spring

Summer-autumn

Annual Meeting, June 15-16 2015, Istanbul, Turkey

NOx conclusions:

Generally too few data in the central North Sea

• The first ”red” areas occurs around 1980 at Odense Fjord and in the Baltic [where no data should be available!]

• From mid 1980ies, full data coverage for 10 year periods [except winter months]

• Most coastline with river output red from 1990ies onward, nutrient rich stream along jutlandic coast from German Bight

• Winter and Autumn have the fewest datapoints, and hence the largest area with >0.5 relative error theshold

• Usually not NOx controlled system in the North Sea

Annual Meeting, June 15-16 2015, Istanbul, Turkey

PO4 Vinter-spring

Summer-autum

Annual Meeting, June 15-16 2015, Istanbul, Turkey

PO4 conclusions:

Winter data

• First yellow data in Bay of Aarhus, then the Channel

• Generally very low numbers in the central North Sea

• Generally more data available, but seems like more missing data than for NOx in the central/british side of the North Sea

• Less pronounced river inputs (except Thames, Holland)

Annual Meeting, June 15-16 2015, Istanbul, Turkey

SiO Vinter-sping

Summer-autumn

Annual Meeting, June 15-16 2015, Istanbul, Turkey

SiO conclusions:

Patterns not as clear cut from rivers as NOx and PO4

• Some increase in Bay of Aarhus and in the Channel

• Not so much from German rivers

• Generally significant less data and more areas masked due to high error.

Rerun of winter nutrients with new DIVA version (?)

- Check timetrend more thoroughly

- Portal upload. We need password for the ocean browser portal + xml metadata creation using divadoxml-gui.

- No logit transform used yet, we have some negative values in the interpolated results. Should we logit transform?

Run DIVA for O2 and Chlorophyll data

Check if enough Hazardous substance data to perform DIVA interpolation

– No seasonality for sediment/biota samples

– maybe on CHASE output to get highest possible spatial output for combined matrices

Border problems with the Baltic (perhaps other areas?) + Baltic data?

Annual Meeting, June 15-16 2015, Istanbul, Turkey

Planning for the last year