Turbulence-permitting air pollution simulation for the Stuttgart metropolitan area

Abstract

Abstract. Air pollution is one of the major challenges in urban areas. It can have a major impact on human health and society and is currently a subject of several litigations in European courts. Information on the level of air pollution is based on near-surface measurements, which are often irregularly distributed along the main traffic roads and provide almost no information about the residential areas and office districts in the cities. To further enhance the process understanding and give scientific support to decision makers, we developed a prototype for an air quality forecasting system (AQFS) within the EU demonstration project “Open Forecast”. For AQFS, the Weather Research and Forecasting model together with its coupled chemistry component (WRF-Chem) is applied for the Stuttgart metropolitan area in Germany. Three model domains from 1.25 km down to a turbulence-permitting resolution of 50 m were used, and a single-layer urban canopy model was active in all domains. As a demonstration case study, 21 January 2019 was selected, which was a heavily polluted day with observed PM10 concentrations exceeding 50 µg m−3. Our results show that the model is able to reasonably simulate the diurnal cycle of surface fluxes and 2 m temperatures as well as evolution of the stable and shallow boundary layer typically occurring in wintertime in Stuttgart. The simulated fields of particulates with a diameter of less than 10 µm (PM10) and nitrogen dioxide (NO2) allow a clear statement about the most heavily polluted areas apart from the irregularly distributed measurement sites. Together with information about the vertical distribution of PM10 and NO2 from the model, AQFS will serve as a valuable tool for air quality forecasting and has the potential of being applied to other cities around the world.

Meteorological, impact and climate perspectives of the 29 June 2017 heavy precipitation event in the Berlin metropolitan area

“…Lateral boundary conditions were provided every 6 hours. The set up of the physical parametrizations is similar to Schwitalla et al (2021) except that 1) the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary layer parametrization Niino, 2006, 2009;Olson et al, 2019) is applied, and 2) the microphysics scheme of Thompson and Eidhammer (2014) (TE2014) is used. Land cover maps have been updated using the high-resolution European Space Agency Climate Change Initiative (ESA CCI) data set (ESA, 2017).…”

Application of the Urban Climate Model PALM-4U to Investigate the Effects of the Diesel Traffic Ban on Air Quality in Stuttgart

“…In a complementary investigation, the WRF model was employed within the Stuttgart metropolitan region to assess the concentration and spatial dispersion of airborne pollutants during the winter season. The simulated data for particulate matter with a diameter of less than 10 µm and nitrogen dioxide enable a lucid identification of areas with heightened pollutant levels, surpassing the irregularly scattered monitoring stations [20]. Moreover, the study extended to the evaluation of model-simulated meteorological, air chemistry, and wall surface variables against in situ measurements taken in the vicinity of Prague, specifically in Degvice, Czech Republic.…”