EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Amazonian Low-Level Jet and its effect on Ozone concentrations above the rain forest

Stefan Wolff1, David Walter1, Anywhere Tsokankunku1, Daiane Brondani2, Fernando Rossato1, Sam Jones3, Sebastian Brill1, Eva Pfannerstill1, Achim Edtbauer1, Rodrigo Souza4, Marta de Oliveira Sá2, Alessandro C. de Araújo5, Cléo Q. Dias-Júnior6, Christopher Pöhlker1, and Matthias Sörgel1
Stefan Wolff et al.
  • 1Multiphase Chemistry, Air Chemistry and Climate Geochemistry Departments, Max Planck Institute for Chemistry, Mainz, Germany
  • 2Instituto Nacional de Pesquisas da Amazônia/ INPA, Manaus, AM, Brazil
  • 3Max Planck Institute for Biogeochemistry, Jena, Germany
  • 4Escola Superior de Tecnologia, Universidade do Estado do Amazonas (UEA), Manaus, AM, Brazil
  • 5Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), Belém, PA, Brazil
  • 6Department of Physics, Federal Institute of Pará (IFPA), Belém, PA, Brazil

The pristine Amazon rainforest is a unique place to study ozone (O3) deposition rates and tropospheric transport, due to the absence of nearby sources of anthropogenic pollution. Parts of the low background O3 are considered to be transported from the stratosphere into the troposphere. This occurs due to general entrainment of stratospheric air at the tropopause. Within the troposphere, downdrafts provide effective vertical mixing and are known to increase surface O3 values. Low-level jets can also enhance O3 concentrations due to long range transport and locally induced mixing in the nocturnal boundary layer. Therefore, we study these phenomena based on long term datasets from 2012 to present from tall measurements towers (80 m and 325 m).

Ozone mixing ratios were measured at the ATTO site (Amazon Tall Tower Observatory) in the Central Amazon (02°08’38.8’’S, 58°59’59.5’’W) since 2012 at 8 different heights between 5 cm and 80 meters and additional measurements from 80 m up to 325 meters are running since 2017. From 2015 to 2017, 3-dimensional wind measurements have been performed in 150 meters height in 10 Hz sampling rate, showing evidences for the formation of a nocturnal low-level jet (LLJ), which leads to higher turbulent mixing inside the residual layer/ stable nocturnal layer. We were comparing the nocturnal LLJ with downdrafts of air due to strong thunderstorms which led to increases of O3 as well. We are analyzing these events regarding their in-canopy air exchange, their frequency and seasonality and comparing them with the effects of the nocturnal LLJ. As the data series comprises more than eight years of data we are also analyzing the interannual variability.

How to cite: Wolff, S., Walter, D., Tsokankunku, A., Brondani, D., Rossato, F., Jones, S., Brill, S., Pfannerstill, E., Edtbauer, A., Souza, R., de Oliveira Sá, M., de Araújo, A. C., Dias-Júnior, C. Q., Pöhlker, C., and Sörgel, M.: The Amazonian Low-Level Jet and its effect on Ozone concentrations above the rain forest, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15847,, 2021.