Estimation of gross primary production for the territory of the Leningrad region and for the territory of the Ladoga carbon site using the OCO-2 measurements.

In order to implement measures to control climate-active gases, as well as to assess the absorption potential of greenhouse gases, the creation of carbon sites in Russia has begun [1]. Each site includes representative ecosystems characteristic of the territory of our country. On the territory belonging to the Federal State Budgetary Institution "Voeikov Main Geophysical Observatory " (~150.6 ha, Leningrad Region, Voeikovo village) [2], it is planned to create the "Ladoga" carbon site, the purpose of which will be the monitoring the climate-active gases fluxes, as well as to assess the absorption potential of greenhouse gases by an ecosystem characteristic of the North-West of Russia (the southern taiga zone and the middle taiga zone in the north of the Leningrad Region). 

Gross primary production (GPP) is a value characterizing the amount of carbon dioxide (CO₂) absorbed by vegetation per unit area as a result of photosynthesis processes. Currently, various methods are used to assess GPP [3], the most effective indicator of plant photosynthesis is sun-induced chlorophyll fluorescence emission, SIF, with a spectral range of ~ 650-800 nm. The linear relationship between SIF and GPP confirmed in the works allows, using satellite measurements of SIF, to estimate the amount of CO₂ absorbed by plants on a regional and global scale, without reference to ground-based measurements [4].

The purpose of this work is to estimate GPP and its temporal variations characteristic of the Leningrad Region (59°-61.2° N, 28°-35.3° E) based on long-term satellite measurements from 2014-2022 using SIF measured by the OCO-2 satellite equipment [5].

Data analysis showed that the GPP in the Leningrad Region, which includes the southern taiga zone and the middle taiga zone, is characterized by an annual cycle, the maximum of which occurs in June, and the minimum – from October to April. The maximum GPP values in the summer period (9–11 gCm^-2day^-1), calculated using OCO-2 data, are comparable with the GPP for the mixed forest zone presented in [6] ~10–12 gCm^-2day^-1.

References

1.    Carbon Supersites, Russian Federation: https://carbon-polygons.ru/ (access 12.11.2024)

2.    Makarova M.V. et al. From carbon polygon to carbon farm: The potential and ways of developing the sequestration carbon industry in the Leningrad Region and St. Petersburg // Vestnik of Saint Petersburg University. Earth Sciences. 2023. V. 68(1) P. 82–102. Doi:10.21638/spbu07.2023.105. 

3.    Liao Z. et al. A critical review of methods, principles and progress for estimating the gross primary productivity of terrestrial ecosystems // Front. Environ. Sci. 2023. V. 11 № 1093095. doi:10.3389/fenvs.2023.1093095.

4.    Li X., Xiao J. TROPOMI observations allow for robust exploration of the relationship between solar- induced chlorophyll fluorescence and terrestrial gross primary production // Remote Sens. of Environ. 2022. V. 268 № 112748. doi:10.1016/j.rse.2021.112748.

5.    Doughty R. et al. Global GOSAT, OCO-2, and OCO-3 solar-induced chlorophyll fluorescence datasets // Earth. Syst. Sci. Data. 2022. V.14. P. 1513–1529. doi.org/10.5194/essd-14-1513-2022.

6.    Lin S. et al. An Open Data Approach for Estimating Vegetation Gross Primary Production at Fine Spatial Resolution // Remote Sensing.2022. V. 14(11) № 2651. doi:10.3390/rs14112651.