Preprints
https://doi.org/10.5194/acp-2021-873
https://doi.org/10.5194/acp-2021-873

  03 Nov 2021

03 Nov 2021

Review status: this preprint is currently under review for the journal ACP.

NEE estimates 2006–2019 over Europe from a pre-operational ensemble-inversion system

Saqr Munassar1, Christian Rödenbeck1, Thomas Koch1,2, Kai U. Totsche3, Michał Gałkowski1,4, Sophia Walther1, and Christoph Gerbig1 Saqr Munassar et al.
  • 1Max-Planck Institute for Biogeochemistry, Jena, Germany
  • 2Meteorological Observatory Hohenpeissenberg, Deutscher Wetterdienst, Hohenpeissenberg, Germany
  • 3Institute of Geoscience, Friedrich Schiller University, Jena, Germany
  • 4AGH University of Science and Technology, Kraków, Poland

Abstract. 3-hourly Net Ecosystem Exchange (NEE) is estimated at spatial scales of 0.25 degrees over the European continent, based on the pre-operational inverse modelling framework CarboScope Regional (CSR) for the years 2006 to 2019. To assess the uncertainty originating from the choice of a-priori flux models and observational data, ensembles of inversions were produced using three terrestrial ecosystem flux models, two ocean flux models, and three sets of atmospheric stations. We find that the station set ensemble accounts for 61 % of the total spread of the annually aggregated fluxes over the full domain when varying all these elements, while the biosphere and ocean ensembles resulted in much smaller contributions to the spread of 28 % and 11 %, respectively. These percentages differ over the specific regions of Europe, based on the availability of atmospheric data. For example, the spread of the biosphere ensemble is prone to be larger in regions that are less constrained by CO2 measurements. We further investigate the unprecedented increase of temperature and simultaneous reduction of Soil Water Content (SWC) observed in 2018 and 2019. We find that NEE estimates during these two years suggest an impact of drought occurrences represented by the reduction of Net Primary Productivity (NPP), which in turn lead to less CO2 uptake across Europe in 2018 and 2019, resulting in anomalies up to 0.13 and 0.07 PgC yr-1 above the climatological mean, respectively. Annual temperature anomalies also exceeded the climatological mean by 0.46 °C in 2018 and by 0.56 °C in 2019, while standardized-precipitation-evaporation-index (SPEI) anomalies declined to −0.20 and −0.05 SPEI units below the climatological mean in both 2018 and 2019, respectively. Therefore, the biogenic fluxes showed a weaker sink of CO2 in both 2018 and 2019 (−0.22±0.05 and −0.28±0.06 PgC yr-1, respectively) in comparison with the mean −0.36±0.07 PgC yr-1 calculated over the full analysed period (i.e., fourteen years). These translate into a continental-wide reduction of the annual sink by 39 % and 22 %, respectively, larger than the typical year-to-year standard deviation of 19 % observed over the full period.

Saqr Munassar et al.

Status: open (until 22 Dec 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Saqr Munassar et al.

Saqr Munassar et al.

Viewed

Total article views: 195 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
152 37 6 195 3 6
  • HTML: 152
  • PDF: 37
  • XML: 6
  • Total: 195
  • BibTeX: 3
  • EndNote: 6
Views and downloads (calculated since 03 Nov 2021)
Cumulative views and downloads (calculated since 03 Nov 2021)

Viewed (geographical distribution)

Total article views: 214 (including HTML, PDF, and XML) Thereof 214 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 01 Dec 2021
Download
Short summary
The results obtained from ensembles of inversions over 13-year show the largest spread in the a-posteriori fluxes over the station set ensemble. using different prior fluxes in the inversions lead to smaller impact. Drought occurrences in 2018 and 2019 affected CO2 fluxes as noticed from NEE estimates. Our study highlights the importance of employing the atmospheric data available across Europe, especially since ICOS established, to better constrain NEE fluxes in the inverse modelling setups.
Altmetrics