Mapping winter nutrient concentrations in the OSPAR maritime area using Diva

Type: Report
Series: RO 52
Author: Örjan Bäck & Magnus Wenzer


The Diva software (Data Interpolating Variational Analysis) software was used to create interpolated gridded fields for nutrient concentrations in the OSPAR maritime area to support the ongoing process to develop common indicators for the MSFD (Marine Strategy Framework Directive). Data were downloaded from the ICES database and maps created for DIN, DIP and silicate for the winter months (December – February) covering the period 2006-2013. Lack of data in areas I and V shifted focus to regions II, III and IV. The most prominent results from the analysis are the high values of nutrient concentrations found along the southern shore of the North Sea.

The lack of data both at a large scale in OSPAR areas I and V and at a smaller scale near the coast, in particular close to river outlets, is the biggest source of error in the Diva analyses. It is evident that there is a need to increase the data coverage for the future work with indicators and for assessment purposes.