Scientist finds an influence of solar activity on European rainfall

Credit: BBC

Interesting result here, although they do admit: ‘The exact mechanism by which the solar signal influences precipitation is still largely unclear and requires further research.’ But the observations have been made.

Source: The GWPF

A balanced level of precipitation provides the basis for a wide range of economic and social activities in Europe. Particularly agriculture, drinking water supply and inland waterway transport are directly affected.

However, the amount of rain fluctuates strongly from year to year. While it may pour torrentially in one year, rain may remain absent for weeks in another year. The population is used to this variability and knows how to deal with it.

The chance discovery by an agricultural scientist from Münster, Germany, now suggests that in certain months rain over Germany and other parts of Europe follows a pattern that up to now has remained undetected.

As part of agricultural consultation, Ludger Laurenz analyzed decades of rainfall records of his home weather station in Münster and noticed a constant up and down that followed an 11-year rhythm – especially in February.

After detailed examination it was clear that this rhythm correlated closely with the activity of the sun: the well-documented 11-year sunspot cycle.

Laurenz next teamed up with two colleagues to examine the extent to which the observed pattern from Münster is reproducible in other parts of Germany and Europe, and whether the phenomenon also exists for the other months of the year. Horst-Joachim Lüdecke from the HTW University of Applied Sciences in Saarland gathered the precipitation data collected in Europe since the beginning of the 20th century.

The physicist emeritus then developed a computer algorithm to determine the similarity of changes in rainfall and solar activity. All 39 European countries and every one of the 12 months of the year were quantified over a total of 115 years using mathematical correlations.

In order to include possible delay effects, the data series of rain and sunspots were systematically checked for shifts. For this purpose, the time series were gradually shifted in time against each other like combs and the respective change of the correlation quality was noted.

The multidimensional data obtained in this way were evaluated for systematic trends by geoscientist Sebastian Lüning and visualized cartographically. Lüning is associated with the Swiss Institute of Hydrography, Geoecology and Climate Sciences (IFHGK) and is specialized in the research of solar climate effects.

The mapped out results show that the link between February precipitation and solar activity originally discovered in Münster is valid for large parts of Central and Northern Europe and has good statistical significance there. Towards southern Europe, however, the correlation weakens significantly.

The statistical investigation was also able to demonstrate systematic phase shifts across the continent.

Continued here.