Long-term Development of Selected Climate Parameters 2013

The Tempelhof measurement site of the German Meteorological Service is located in the inner-city area, about 2.5 km south of the eastern city centre, on the southern edge of the Tempelhofer Feld, the former central Tempelhof Airport, which is characterised by green and free spaces. The wind measurements are taken at a height of 10 m above ground. Measurements for this station go back to the beginning of 1948.

For the Berlin-Tempelhof measurement station, data from about 65 years of weather records are available for the present evaluations; only the Potsdam time series goes back (albeit significantly) further.

Long-term mean values

Table 6.2 gives an overview of the long-term monthly mean values of selected climate parameters at the Tempelhof station in the 30-year period 1981 to 2010 under consideration.

The climate diagram of the Tempelhof station is shown in Figure 6.1. In Berlin-Tempelhof, the distribution of precipitation in the summer months is slightly shifted with respect to the other stations. The month with the most precipitation in the entire year is already June, not August.

The following figures show wind direction distributions at the Tempelhof station in the period from 2001 to 2010. In addition to the mean long-term wind direction distribution, distributions for low-wind conditions with speeds up to 2 m/s as well as conditions with wind speeds above 2 m/s were evaluated. Low-wind conditions were recorded in 17.5 % of the cases in the period under consideration. Calms were observed in 0.2 % of the situations. Wind speeds above 2 m/s occurred in 82.5 % of the evaluated period. Further, wind direction distributions were evaluated for the summer and winter half-years. For both half-years, winds from 270° occur with the highest frequencies. While the secondary maximum is formed by winds from the east in the summer half-year, winds from southwestern directions occur with the second-highest frequency in the winter half-year.

The red ring lines in the diagrams indicate the mean frequencies of occurrence of the wind direction in the respective period under consideration in percent. The distance between ring lines corresponds to 1 %.

Developments, trends

Figure 6.6 shows the history of the annual mean temperature of the years 1948 to 2013. The trend is increasing over the course of the measurement series, as for all other stations, by about 1 Kelvin. Here, too, a period of significantly lower temperatures between the mid-1950s until around 1970 can be discerned.

For the summerly threshold days, regardless of the respective measurement period Figures 6.7 and 6.8 show a strong increase in summer days, in the longer trend since 1948 by 17 summer days. The number of hot days increases by about six days. While the history of the number of tropical nights exhibits no trend, the relatively high number of nighttime hours with temperatures not below 20 °C at this open site is notable. In the summer of 1994, the highest hitherto recorded number of 10 tropical nights occurred. The warmest summer night was measured with a minimum temperature of 23.4 °C in the summer of 2010 on July 11.

Despite the high number of tropical nights, these mostly occur individually and not consecutively. 1994 is a ‘special’ year with record values: From July 26 to August 2, the temperature did not fall below 20 °C in eight consecutive nights; during the days, too, there was a heat wave, so that on eleven consecutive days (July 22 to August 1, 1994) the daily maximum values were above 30 °C (cf. Fig. 6.9).

The winterly threshold days frost day and ice day exhibited a negative trend also at the Berlin-Tempelhof station. The frost days decreased by about seven days since records began in Tempelhof; the ice days decreased by 4 days per year in the trend (cf. Fig. 6.10).

In the representation focused on the 30-year period 1981 to 2010, it is notable that here the trend exhibits an increase in the frost days. This is due to the very high number of these threshold days in 1996 and 2010 (cf. Fig. 6.11 as well as Fig. 5.9 for the Tegel station).