Influencing parameters far away from the Rhine and Elbe
The analysis is based on global ocean and climate data going back almost seven decades. The two AWI scientists search these datasets for relationships between the water volume in selected rivers and key weather, ocean or soil parameters, like the surface temperature and sea level pressure in specific ocean regions. Temperature, precipitation and soil moisture at the source and in the drainage basin of each river also play an important part. “For the water levels in the Rhine and Elbe, the sea surface temperature in the North Atlantic is the crucial factor. It has a significant influence on the weather in Central Europe and, simply put, determines which course storms and rain will take,” reports Monica Ionita.
Relationships that are identified as ‘reliable’ are fed into the model – not for all rivers at once, but for each one individually. Lastly the researchers adapt their model to the respective season, since completely different independent parameters may be relevant for the same river in spring than in autumn.
For concrete forecasts, the AWI experts collect real-time data on all relevant weather and environmental parameters for the previous months and feed them into their statistical model. Using computers, they then calculate how much water will flow through a particular point of the river in a particular period. Based on this figure, the researchers can estimate how the water level will develop.