Estimates of anthropogenic CO2 emissions from satellite and ground based measurements

Y. Timofeyev1, G. Nerobelov1, S. Smyshlyaev2, I. Berezin1, Y. Virolainen1, M. Makarova1, A. Poberovsky1, A. Polyakov1, and S. Foka1

1Saint-Petersburg State University, Saint-Petersburg, Russian Federation (y.timofeev@spbu.ru)

2Russian State Hydrometeorological University, Saint-Petersburg, Russian Federation (smyshl@rshu.ru)

The influence of greenhouse gases on Earth climate motivated people to establish monitoring systems and set a task before humanity to mitigate anthropogenic emissions of the gases (e.g. CO2) in the coming decades. Megacities of our planet significantly (up to ⁓70%) define CO2 anthropogenic emissions therefore it is important to maintain control of cities` emissions. In these days there are different methods of the anthropogenic emission estimations which start with bottom-up approach and end with satellite measurements. The method which based on satellite observations is a combination of atmospheric optics and transport inverse problems. Firstly, one resolves the inverse problem to retrieve spatio-temporal variation of gas from the measurements of outgoing Sun reflected or thermal Earth radiation. Secondly, using the derived information the inverse problem of determination of anthropogenic emissions is resolved. The merits of satellite methods are that they provide independent monitoring of emissions and can contribute to its control according to the standards accepted in the world. The uncertainties of the satellite-based approach can vary up to 50% and depend on many factors which include the number and accuracy of measurements used, quality of prior information, atmospheric conditions, chemistry transport model and others. Thereby satellite measurements require validation by comparison to, for example, ground-based estimations of anthropogenic emissions.

 In our study we compared CO2 emission retrievals based on satellite and ground-based remote measurements with emissions obtained by the bottom-up approach which based on calculations of the emissions using anthropogenic activity data and with other sources. In July 2014 a satellite OCO-2 was launched to study atmospheric carbon dioxide. OCO-2 data was used for the period 2014-2018 to estimate anthropogenic CO2 emissions from the territories of Saint-Petersburg by using measurements at upwind (clean air) and downwind (polluted air) locations on the opposite sides of the city [1]. Example of the measurements can be seen in Fig.1. In 2019, the Emission Monitoring Mobile Experiment (EMME) was conducted within the St. Petersburg agglomeration aiming to estimate the emission intensity of greenhouse (CO2, CH4) and reactive (CO, NOx) gases for St. Petersburg. St. Petersburg State University (Russia), Karlsruhe Institute of Technology (Germany) and the University of Bremen (Germany) jointly ran the experiment [2]. The core instruments of the campaign were two portable Fourier-transform infrared spectrometers Bruker EM27/SUN which were used for ground-based remote sensing measurements of the total column amount of CO2, CH4 and CO at upwind and downwind locations around the city. Anthropogenic emissions based on satellite and ground-based approaches as well as on bottom-up method and emissions from other sources (CAMS, EDGAR, ODIAC databases) are presented in Table 1. To derive CO2 emissions, the EMME observations were processed by two different methods whose results differ on 10-15%. Our ground-based estimations have good agreement with CAMS and EDGAR databases. By contrast, St. Petersburg CO2 emissions according to the satellite-based and bottom-up approaches and ODIAC database are significantly lower. The presented results demonstrate the importance of the validation of CO2 anthropogenic emissions retrieved by satellite approach.

Figure 1. Latitudinal distribution of XCO2 measured by OCO-2 for the clean (blue points) and polluted (pink points) air in Moscow, 25 and 27 Aug 2018

Table 1. Different estimations of St. Petersburg CO2 emissions

Source of dataCO2 emissions, Mt/year
EMME (2019), v.1City – 78, City center – 47
EMME (2019), v.2City – 65, City center – 40
ОСО-238-41
Bottom-up30
ODIACCity – 34, City center – 21
EDGAR64
CAMS67

References

1. Timofeev Yu.M., Berezin I.A., Virolainen Ya.A., Poberovsky A.V., Makarova M.V., Polyakov A.V. Estimates of anthropogenic CO2 emissions for Moscow and St. Petersburg based on OCO-2 satellite measurements. // Optika Atmosfery i Okeana. 2020. V. 33. No. 04. P. 261–265

The visual presention slides for this work presented in the European Geosciences Union 2020 conference (EGU20) can be found in this link.

2. M.V. Makarova, F. Hase, D.V. Ionov, T. Blumenstock, T.Warneke, S.C. Foka, Y. A. Virolainen, V.S. Kostsov, C.Alberti, M. Frey, A.V. Poberovskii, Y. M. Timofeyev, K.A. Volkova, N.A. Zaitsev, E.Y. Biryukov, S.I. Osipov, B. K. Makarov, А.V. Polyakov, N.N. Paramonova, V.M. Ivakhov, H.H. Imhasin, E. F. Mikhailov. Emission Monitoring Mobile Experiment (EMME): an overview and first results of the St. Petersburg megacity campaign-2019.  Atmos. Chem. Phys.

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