An unexpected pattern of distinct weekly periodicities in climatological variables in Germany

Abstract

[1] Statistical analyses of data from 12 German meteorological stations meeting WMO standards in the period 1991 -2005 are presented. These stations represent different local climate conditions in terms of both meteorology and pollution situation. For the average over data of all stations, we identified significant weekly periodicities in many variables such as temperature, daily temperature range, sunshine duration, cloud amount, precipitation, and precipitation frequency. Not only data of stations situated in congested urban areas, but also data of remote stations as e.g. on Mount Zugspitze 2960 m above sea level in the Alps showed significant in-phase weekly cycles. These weekly periodicities cannot be explained completely by local pollution effects or local heat emissions. We tend towards the hypothesis that the anthropogenic weekly emission cycle and the subsequent aerosol cycle interact with the atmospheric dynamics on a larger scale which leads to a forcing of a naturally existing 7-day period among the spectrum of atmospheric periods.

Assessing large-scale weekly cycles in meteorological variables: a review

“…They analysed annual rainfall and temperature time series with help of a bootstrapping method using observations partly dating back to 1871. Their results confirm significant WCs in Tmax, Tmin, and DTR over Germany, which are partly in agreement with Bäumer and Vogel's (2007) results. Apart from the results of Bäumer and Vogel (2007), Laux and Kunstmann (2008) found Thursday being the day of the week with the largest positive temperature anomalies.…”

“…Their results confirm significant WCs in Tmax, Tmin, and DTR over Germany, which are partly in agreement with Bäumer and Vogel's (2007) results. Apart from the results of Bäumer and Vogel (2007), Laux and Kunstmann (2008) found Thursday being the day of the week with the largest positive temperature anomalies. They found a significant weekly signal for temperature in most European countries (except for Finland), but with an unclear pattern in the spatial distribution of the weekly anomalies (see Fig.…”

“…It is speculated that the atmospheric circulation pattern, possibly triggered by regional accumulation of air pollutants in the lower atmosphere could play a major role. On the other hand, no significant weekly differences are found in the rainfall series, which is in contradiction with the results of Bäumer and Vogel (2007). Barmet et al (2009) Quaas et al (2009) published a work trying to verify the possible WCs over a large area in Europe using, for the first time to our knowledge, two state-of-art global climate models (GCM).…”

“…Their results confirmed a non-significant signal in the major part of the analysed sites, pointing out that this finding can be considered "interesting and perhaps surprising" as they found clear significant DTR weekend effect over other developed/polluted areas in the world. Bäumer and Vogel (2007) Bäumer and Vogel (2007) can be considered significant, and suggested that neglecting "spatial auto-correlation while assessing the statistical significance of the merged time series" could probably explain why found significant WCs. In their reply, argued that the analysis performed by Hendricks Franssen (2008) for the two Swiss stations does not imply any scientifically sound conclusions for Germany.…”

“…They also argued that daily precipitation shows a limited spatial auto-correlation. Laux and Kunstmann (2008) extended the work of Bäumer and Vogel (2007), considering more meteorological stations in Germany, as well as eight more countries over Central and Northern Europe (Denmark, France, Finland, Great Britain, Ireland, Iceland, Norway, and Sweden). They analysed annual rainfall and temperature time series with help of a bootstrapping method using observations partly dating back to 1871.…”