WP12. Hindcast and scenario studies on coastal-shelf climate and ecosystem variability and change Why? (in addition to the call text) Need to relate “today’s” operational status and short term forecast to the “normal” climatological status and variability. Indexes or anomalies from climatology may be of more value to science and management (e.g. fisheries) than absolute values with large errors. Due to the scarcity of observations in the ocean, climatologies must for most areas be produced by 3D numerical models run for several decades. Similar length of time-series very useful for….

Objectives To quantify the monthly to decadal variability of the shelf seas-coastal climate. To quantify the monthly to decadal variability of the climate effects on the lower trophic levels of the shelf seas-coastal ecosystems. To quantify the potential effects on shelf seas- coastal climate and ecosystems from global climate change predictions (decades-100 years). To quantify the potential effects on shelf seas- coastal ecosystems due to management scenarios and related to natural variability. To produce multi-decadal reference databases and monthly climatologies of modelled shelf seas-coastal climate and ecosystems.

Management scenario studies will mainly be related to eutrophication and harmful algal bloom issues. Scenarios studying the effects of reduced/increased loads of individual nutrients from individual rivers and nitrogen from the atmosphere will shed light on the potential effects of management actions seen in relation to natural climate variability and the potential/ predicted climate change. (One particular study is to quantify the coastal ecosystem effect of the seasonal change in freshwater supplies due to existing and/or planned hydroelectric power plants).

Long time series There is a great need for historic databases of 3D model results first of all to produce long-term information on changes that has not been observed trough regular monitoring. Examples of such are time series on: cross boundary transport of water masses, heat, salt, nutrients, plankton and fish larvae; distribution of water masses, positioning of fronts, distribution of fish larvae, primary production, timing of spring bloom, changes in coastal circulation patterns/ intensity etc. etc.

Task 12.1 Quantify the monthly to decadal variability of the ocean physics/ climate This includes monthly integrated values from the last years of temperature, salinity, turbulence, 3D currents, kinetic energy and potential energy at selected depths or depth intervals, mixed layer thickness, and volume, heat and salt fluxes through selected sections. Validation of precision and accuracy.

Task 12.2 Quantify the monthly to decadal variability of the climate effects on the lower trophic levels of the shelf seas-coastal ecosystems. This includes monthly integrated values from the last years of primary production, concentrations of functional groups of algae, nutrients and nutrient ratios, oxygen, and sedimentation, and cross boundary time series of transports of nutrients and particulate matter through selected sections. Validation of precision and accuracy.

Task 11.3 Quantify the potential effects on shelf seas-coastal climate and ecosystems from global climate change predictions (decades-100 years). This includes running the models used in Task 12.1&2 for some years in the future (say around 2040, 2070, 2100 with forcing from the coupled climate prediction models, and producing similar monthly averaged results as in Task 12.1 & 12.2.

Task 12.4 Quantify the potential effects on shelf seas-coastal ecosystems from management scenarios and related to natural variability. This includes running selected “what if” scenarios studying the effects of reduced (and maybe increased) loads of individual nutrients from individual areas/rivers and nitrogen from the atmosphere to shed light on the potential effects of management actions seen in relation to natural climate variability and the potential/ predicted climate change. The simulations needs to be run for multi-year periods with typically large differences in climate/ weather to study and compare the effects on the state variables as described in Task 12.2

Task 12.5 Produce multi-decadal reference databases and monthly climatologies of modelled shelf seas- coastal climate and ecosystems The full 3-D results from the long-term simulations in Task 12.1 & 2 will be stored as 3- day? averages in an easy accessible database. Monthly means and monthly climatologies will also be produced and stored in the same database.

Do we want this? Can we do it? in what areas? and with what resolution?