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Modulation of earth surface air warming by long-term variations of global radiation in Central Europe    
  • Jürg Thudium,
  • Carine Chelala
Jürg Thudium

Corresponding Author:thudium@oekoscience.ch

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Carine Chelala


Atmospheric aerosol affects the Earth’s radiation budget. Different studies have shown that increasing air pollution from about 1950-1980 in Europe led to a continuous weakening of global radiation at the earth’s surface (global dimming), but during the subsequent improvement of air quality, an increase occurred again (global brightening). Global brightening, which has continued until at least 2020, has more than compensated for global dimming. In this study, a quantitative estimation of the influence of the fluctuating global radiation on surface air temperature was carried out with the help of a multiple linear regression model based on monthly values from the period 1950-2020, i.e. including the phase of global brightening and global dimming. The applicability of this approach was ensured by a set of five statistical standard tests. Sunshine duration, global radiation and temperature data from 6 measuring stations from the national weather services in Austria, Switzerland and Germany were analyzed.
The overall temperature increase from 1950-2020 is dominated by the temporally continuous temperature increase (global warming). However, a fraction of the increase (+0.3 °C resp. +0.5 °C for the entire year resp. summer half-year) is attributed to the increase of global radiation.
With regard to the brightening period in the last four decades (ca. 1980-2020), the fraction of the increase of global radiation within the total temperature increase is substantial: about one third for the entire year (ca. +0.6 °C), even half for the summer half-year (ca. +1.1 °C). The model results are reasonable in view of the comparison with the temperature measurements at the 6 stations.