Workpackage 1: Climate change impact on runoff, nutrient flows, and regime of the Baltic Sea.

WP coordinator is Uldis Bethers, Dr. Phys., Faculty of Physics and Mathematics, UL. WP participants are researchers of the Laboratory of Modelling of Environmental and Technological Processes (FPhM, UL), Faculty of Geography and Earth Sciences (UL), Institute of Biology (UL).

WP will prepare data series and will provide analytical and modelling support to the other WPs. Each date series will consist of 3-5 scenarios describing 50 – 100 year period with a resolution of 1 day.

Data series will include:

1) Meteorological data sets corresponding with the climate change scenarios
(2) Runoff and nutrient flow data sets calculated by means of mathematical modelling
3) Long-term predictions of the Gulf of Riga physical properties and processes based upon runoff /loading forecast.

Models developed by the WP will be based on the global atmospheric circulation models and their own-scaling to regional level. Models will be calibrated verified by means of comparison with historical data with hind-casting results. Model systems will then be utilized for calculations of the drainage basin and marine state, using predicted climate variables as input data. Thus the methods routinely used for assessment of observation data series will be used to analyse possible future situations.

WP1 tasks are:

• Assess and adopt regional climate change models to generate data sets characterizing water body status with necessary temporal and spatial resolution (Climate Scenarios).
• Forecast climate change impact on river runoff and its seasonal variation. Assess and model long-term runoff variation (Runoff and Nutrient Loads).
• Adopt 3D marine physical models to produce data sets for projection of bio-geochemistry and ecosystem evolution (Marine Physical Model).
• Provide modeling support to other WPs(Modeling Support).

WP1 outputs will be:

• Quantitative climate scenarios in a form of data series based on analysis of climate change characteristics and critical factors.
• Regionally adopted drainage basin model (water, nutrient flow) for the territory of Latvia
• Prediction of climate change impact on river runoff, its seasonal and long-term variation.
• Predictive data series of water runoff and nutrient loading to the sea from the territory of Latvia.
• Regionally adapted 3D model of marine state.
• 3D calculations of the Gulf of Riga ecosystem variables based on climate change scenarios.
• Analysis of model calculations.