1. Changes in black carbon emissions over Europe due to COVID-19 lockdownsNikolaos Evangeliou, Stephen M. Platt, Sabine Eckhardt, Cathrine Lund Myhre, Paolo Laj, L. Alados-Arboledas, John Backman, Benjamin T. Brem, Markus Fiebig, Jesús Yus-Díez, 2021, original scientific article Abstract: Abstract. Following the emergence of the severe acute respiratory syndrome coronavirus
2 (SARS-CoV-2) responsible for COVID-19 in December 2019 in Wuhan (China)
and its spread to the rest of the world, the World Health Organization
declared a global pandemic in March 2020. Without effective treatment in the
initial pandemic phase, social distancing and mandatory quarantines were
introduced as the only available preventative measure. In contrast to the
detrimental societal impacts, air quality improved in all countries in which
strict lockdowns were applied, due to lower pollutant emissions. Here we
investigate the effects of the COVID-19 lockdowns in Europe on ambient black
carbon (BC), which affects climate and damages health, using in situ
observations from 17 European stations in a Bayesian inversion framework. BC
emissions declined by 23 kt in Europe (20 % in Italy, 40 % in Germany,
34 % in Spain, 22 % in France) during lockdowns compared to the same
period in the previous 5 years, which is partially attributed to COVID-19
measures. BC temporal variation in the countries enduring the most drastic
restrictions showed the most distinct lockdown impacts. Increased particle
light absorption in the beginning of the lockdown, confirmed by assimilated
satellite and remote sensing data, suggests residential combustion was the
dominant BC source. Accordingly, in central and Eastern Europe, which
experienced lower than average temperatures, BC was elevated compared to the
previous 5 years. Nevertheless, an average decrease of 11 % was seen
for the whole of Europe compared to the start of the lockdown period, with
the highest peaks in France (42 %), Germany (21 %), UK (13 %), Spain
(11 %) and Italy (8 %). Such a decrease was not seen in the previous
years, which also confirms the impact of COVID-19 on the European emissions
of BC. Keywords: black carbon, covid-19, emissions, Europe Published in RUNG: 13.05.2024; Views: 126; Downloads: 3 Full text (11,03 MB) This document has many files! More... |
2. Gravity wave instability structures and turbulence from more than 1.5 years of OH[ast] airglow imager observations in SloveniaRené Sedlak, Patrick Hannawald, Carsten Schmidt, Sabine Wüst, Michael Bittner, Samo Stanič, 2021, original scientific article Abstract: We analyzed 286 nights of data from the OH* airglow imager FAIM 3 (Fast Airglow IMager) acquired at Otlica Observatory, Slovenia, between 26 October 2017 and 6 June 2019. Measurements were performed with a spatial resolution of 24 m per pixel and a temporal resolution of 2.8 s. Multiple turbulence episodes were observed and the energy dissipation rate in the upper mesosphere/lower thermosphere region was estimated from image sequences in 25 cases. Values range around 0.08 and 9.03 W/kg and would lead to an approximated localized maximum heating of 0.03–3.02 K per turbulence event. Keywords: upper mesosphere, lower thermosphere, remote sensing, gravity waves, turbulence, Bora episodes Published in RUNG: 25.10.2021; Views: 1884; Downloads: 0 This document has many files! More... |
3. Orographic gravity waves in OH-airglow imaging systemsSabine Wuest, Jonas Till, René Sedlak, Patrick Hannawald, Carsten Schmidt, Samo Stanič, Michael Bittner, 2020, published scientific conference contribution abstract Abstract: Atmospheric dynamics is strongly influenced by waves on different scales. Airflow over mountains can lead to all kinds of atmospheric waves, planetary and gravity waves as well as infrasound. Under certain circumstances these waves can propagate through the atmosphere and lead to a re- distribution of energy. In the case of gravity waves, a stably stratified atmosphere is a mandatory requirement for their generation and vertical propagation. Additionally, the vertical propagation depends on the horizontal wind field. In the Alpine and pre-Alpine region, we currently operate five OH-airglow imaging systems, which allow the investigation of orographic gravity waves. Depending on tropo-, strato- and mesospheric wind and temperature, it is checked which wavelengths can propagate into the fields of view of our instruments. This is done for a whole year in order to take into account annual and semi- annual cycles in wind and temperature. Concerning the generation of gravity waves, we put our focus on our OH-airglow imager (FAIM) deployed at Otlica (45.9°N, 13.9°E), Slovenia. Here, we also have additional measurements of an OH-airglow spectrometer (GRIPS). In case studies, we investigate whether strong wind events (Bora) lead to strong gravity waves activity or enhanced potential energy density. Keywords: Orographic gravity waves, Bora, Otlica, Slovenia, OH-airglow imaging Published in RUNG: 08.10.2020; Views: 2539; Downloads: 0 This document has many files! More... |