In Delhi, the sun sometimes disappears behind a brown haze. This smog is not only unhealthy, it also affects the climate. An international research team led by the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig has now discovered why previous climate models for heavily polluted cities only inaccurately depict important processes.
The key lies in tiny particles known as aerosols. These are the finest particles and droplets in the air, created for example by car exhaust fumes, industry or desert dust. They influence the climate in two ways: they reflect sunlight and at the same time act as nuclei for cloud formation. Scientists call the amount of water a particle can absorb hygroscopicity. The higher it is, the more the particles grow and the greater their cooling effect on the atmosphere can be.
Artificial intelligence helps with calculations
The team used machine learning to better understand this. This is a form of artificial intelligence that recognizes patterns in large amounts of data. The researchers analyzed measurements from ten locations on four continents, including Beijing, Cairo, Delhi, Paris and the research vessel Polarstern in the Atlantic. Two measuring stations in Germany, Goldlauter and Melpitz, were also included in the analysis.
The result significantly improves the basis for climate models. "Our results underline the importance of regional aerosol parameterizations as a decisive step towards reducing uncertainties in the estimation of direct radiative forcing in next-generation climate models," emphasizes Mira Pöhlker from TROPOS and the University of Leipzig. She also explains that the new calculations could influence how much solar energy the Earth stores regionally or reflects back into space. Even small changes are climatically relevant worldwide.
The research team now hopes that the new algorithm will be integrated into global climate models in the future. This could make more precise predictions about how aerosols influence climate and cloud formation possible.
More information on this can be found here.
