EGU22-2432, updated on 09 Jan 2023
https://doi.org/10.5194/egusphere-egu22-2432
EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Analysis of the dependency of atmospheric formaldehyde - as a proxy for bVOC emissions - on vegetation status over a Central European city and potential implications for surface ozone exceedances

Heidelinde Trimmel1, Monika Mayer1, Stefan Schreier1, Christian Schmidt1, Ramiro Checa-Garcia1, Josef Eitzinger1, Anne Charlott Fitzky2, Thomas Karl3, Peter Huszár4, Jan Karlický4, Paul Hamer5, Philipp Koehler6, and Christian Frankenberg6
Heidelinde Trimmel et al.
  • 1Institute of Meteorology and Climatology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
  • 2Institute of Forest Ecology, Dept. of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
  • 3Department of Atmospheric Physics, Charles University (CUNI), Prague, Czech Republic
  • 4Norsk institutt for luftforskning (NILU), Kjeller, Norway
  • 5Institute of Atmospheric and Cryospheric Sciences, University of Innsbruck, Innsbruck, Austria
  • 6California Institute of Technology (Caltech), Pasadena, USA

In the city centre of Vienna, Austria ozone (maximum 8 hour mean) mda8 exceedances of the threshold value of 120 μg/m³ can occur from as early as March until September, which coincides with the main local vegetation season. Biogenic volatile organic compounds (bVOCs), which are mainly emitted by forests, but also other vegetation as agricultural field crops and are precursor substances to atmospheric formaldehyde (HCHO). Thereby they contribute to the production of ozone in and around the city. On the other hand, vegetated areas reduce the ozone concentration by uptake via stomatal and cuticular pathways and soil uptake.

In this study the dependency of HCHO mixing ratios, obtained from path averaged MAX-DOAS UV retrievals over the Vienna city centre, on meteorological parameters (air temperature, global radiation, boundary layer height) and vegetation drought stress indicators are analysed, focusing on the difference between drought and non-drought conditions. Following indicators are used: standardized precipitation index (SPI), relative soil saturation from the Agricultural Risk Information System (ARIS), vapour pressure deficit and satellite-based photosynthetically active radiation anomaly (fAPAR) as well as solar-induced chlorophyll fluorescence (SIF).

A clear dependency of the HCHO on vegetation-related parameters and the area of origin of HCHO and its precursor substances is found. However, the strength of the relationship between the parameters changes depending on the vegetation status. The results of the observational HCHO analyses spanning 2017-2021 are compared with bVOCs estimates of the Model of Emissions of Gases and Aerosols from Nature (MEGAN). The observed ozone concentrations are compared with the ozone mixing ratios and dry deposition rates calculated by the chemical transport model developed at Meteorological Synthesizing Centre-West within the European Monitoring and Evaluation Program (EMEP MSC-W model), which includes the Deposition of Ozone for Stomatal Exchange (DO3SE) model, to better understand timing and magnitudes of sources and sinks. Possible consequences for exceedances of the mda8 ozone target value in the study region are discussed.

How to cite: Trimmel, H., Mayer, M., Schreier, S., Schmidt, C., Checa-Garcia, R., Eitzinger, J., Fitzky, A. C., Karl, T., Huszár, P., Karlický, J., Hamer, P., Koehler, P., and Frankenberg, C.: Analysis of the dependency of atmospheric formaldehyde - as a proxy for bVOC emissions - on vegetation status over a Central European city and potential implications for surface ozone exceedances, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2432, https://doi.org/10.5194/egusphere-egu22-2432, 2022.