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This archive contains the scripts and notebooks needed to run the tools presented in "Measurement report: Eight years of greenhouse gas fluxes at Saclay, France, estimated with the Radon Tracer Method" (Yver et al., 2025). There are dependencies with files on the ICOS Carbon Portal Jupyter Service and it can only be run there. To do so, login to any of our Jupyter services (https://www.icos-cp.eu/data-services/tools/jupyter-notebook) or request access:
upload and unzip the archive and open the main notebook “RTM_widget.ipynb”.
The ICOS (Integrated Carbon Observation System) network of atmospheric measurement stations produces standardized data on greenhouse gas concentrations but also on radon concentrations for a subset of the stations.
The Radon Tracer Method (RTM) involves simultaneous measurements of radon (222 Rn) and GHG at co-located sites, along with the estimation of a radon source function. Radon is particularly useful because it is a naturally occurring radioactive gas with a well-defined source (soil), a simple sink (half-life of 3.82 days), and chemical inertness. Due to these properties, radon can be used effectively as a tool for estimating and verifying GHG fluxes. Indeed, like GHGs which usually have their sources close to the ground, 222 Rn accumulates during the night within the lower boundary layer. Thus, both 222 Rn and GHGs will accumulate together overnight and their correlation can be used to estimate the flux of GHG as long as we know the exhalation rate of 222 Rn.
An interactive tool to apply the RTM to estimate GHG fluxes from ICOS atmospheric concentration measurement was developed. The code is written in Python and is hosted on the ICOS Carbon Portal (CP) JupyterLab. It thus takes advantage of the ICOS CP Python package to access ICOS site data and already calculated footprints. It uses the footprints already calculated by the Lagrangian model STILT as configured on the CP. The STILT footprints are available every 3 hours and cover the region 33°S–73°N, 15°W–35°E with a resolution of 1/12° by 1/8°, approximately 10 km x 10 km. The STILT model is forced with the European Centre for Medium-Range Weather Forecast (ECMWF) Integrated Forecasting System (IFS) operational analysis. As these footprints are initially calculated for CO2, no term for the radon radioactive decay has been added. By default, these footprints are going back in time for 10 days which is not suitable for this application. To correct this issue, we decided to apply a mask over the footprint representing the zone usually covered when going backward 5 to 10 hours only. To do so, we calculated the mean wind speed over our period of study for the nights we had events. This average, 6 m s−1 , multiplied over the 8 hours of our nocturnal window, gave us a radius of about 175 km. From this distance, we applied a rectangular mask centered on Saclay running from -0.24°W to 4.53°W and 50.28°N to 47.15°N. We recommend to do the same for the site studied. The radon exhalation maps used are the two new maps developed in the project 19ENV01 traceRadon (using new input data sets such as soil uranium content and physical soil properties and either the reanalysed moisture data from ERA5-Land (Muñoz Sabater, 2019) or GLDAS-Noah2.1 (Beaudoing and Rodell, 2020)) with a value per day and available from 2017 to 2024. Their resolution is 0.05°x0.05° approximately 5.5 km latitude x 3.7 km longitude. All maps can be downloaded from the ICOS CP (Karstens and Levin, 2023, 2024). The radon exhalation maps and the footprints use different grids. Therefore, when combined, the radon exhalation maps are regridded to match the footprints. The site to study can be chosen from the list available on the CP. The RTM can be applied to different species when data are available (CO2 , CH4 , N2 O and CO). Then, either it extracts the data from the CP Near Real Time hourly data or if the user has an access to the ICOS Atmosphere Thematic Center database with extraction rights for this site, data with a shorter timestep (minute data) can be extracted directly from the ICOS database and averaged on a 30 minute window to match the highest resolution for the radon data. By default, the code applies the RTM equation for the data between 21:00 to 06:00 UTC, which is a suitable window for central Europe where most of the ICOS stations are located, but this window can be modified to fit with other latitudes or longitudes for example to accommodate the shorter summer nights in northern Europe. The length of the window can be modified as well, for example to reproduce the tests from Levin et al. (2021). We apply an orthogonal distance regression using the SciPy.odr package.No other criteria are applied initially but the correlation coefficient, the error in the linear regression, the number of data points and hours available for the calculation, the radon accumulation level and whether the radon rise stopped before 08:00 UTC are recorded so the data can be filtered in a second step.
@misc{https://doi.org/10.18160/rtm0-2025,
doi = {10.18160/RTM0-2025},
url = {https://meta.icos-cp.eu/objects/7IbIMEpNs-hbjHEzyKu2BZQB},
author = {Yver, Camille},
title = {Radon Tracer Method tool},
publisher = {ICOS ERIC - Carbon Portal},
year = {2025},
copyright = {Creative Commons Attribution 4.0 International}
}
TY - COMP T1 - Radon Tracer Method tool AU - Yver, Camille DO - 10.18160/RTM0-2025 UR - https://meta.icos-cp.eu/objects/7IbIMEpNs-hbjHEzyKu2BZQB AB - The ICOS (Integrated Carbon Observation System) network of atmospheric measurement stations produces standardized data on greenhouse gas concentrations but also on radon concentrations for a subset of the stations. The Radon Tracer Method (RTM) involves simultaneous measurements of radon (222 Rn) and GHG at co-located sites, along with the estimation of a radon source function. Radon is particularly useful because it is a naturally occurring radioactive gas with a well-defined source (soil), a simple sink (half-life of 3.82 days), and chemical inertness. Due to these properties, radon can be used effectively as a tool for estimating and verifying GHG fluxes. Indeed, like GHGs which usually have their sources close to the ground, 222 Rn accumulates during the night within the lower boundary layer. Thus, both 222 Rn and GHGs will accumulate together overnight and their correlation can be used to estimate the flux of GHG as long as we know the exhalation rate of 222 Rn. An interactive tool to apply the RTM to estimate GHG fluxes from ICOS atmospheric concentration measurement was developed. The code is written in Python and is hosted on the ICOS Carbon Portal (CP) JupyterLab. It thus takes advantage of the ICOS CP Python package to access ICOS site data and already calculated footprints. It uses the footprints already calculated by the Lagrangian model STILT as configured on the CP. The STILT footprints are available every 3 hours and cover the region 33°S–73°N, 15°W–35°E with a resolution of 1/12° by 1/8°, approximately 10 km x 10 km. The STILT model is forced with the European Centre for Medium-Range Weather Forecast (ECMWF) Integrated Forecasting System (IFS) operational analysis. As these footprints are initially calculated for CO2, no term for the radon radioactive decay has been added. By default, these footprints are going back in time for 10 days which is not suitable for this application. To correct this issue, we decided to apply a mask over the footprint representing the zone usually covered when going backward 5 to 10 hours only. To do so, we calculated the mean wind speed over our period of study for the nights we had events. This average, 6 m s−1 , multiplied over the 8 hours of our nocturnal window, gave us a radius of about 175 km. From this distance, we applied a rectangular mask centered on Saclay running from -0.24°W to 4.53°W and 50.28°N to 47.15°N. We recommend to do the same for the site studied. The radon exhalation maps used are the two new maps developed in the project 19ENV01 traceRadon (using new input data sets such as soil uranium content and physical soil properties and either the reanalysed moisture data from ERA5-Land (Muñoz Sabater, 2019) or GLDAS-Noah2.1 (Beaudoing and Rodell, 2020)) with a value per day and available from 2017 to 2024. Their resolution is 0.05°x0.05° approximately 5.5 km latitude x 3.7 km longitude. All maps can be downloaded from the ICOS CP (Karstens and Levin, 2023, 2024). The radon exhalation maps and the footprints use different grids. Therefore, when combined, the radon exhalation maps are regridded to match the footprints. The site to study can be chosen from the list available on the CP. The RTM can be applied to different species when data are available (CO2 , CH4 , N2 O and CO). Then, either it extracts the data from the CP Near Real Time hourly data or if the user has an access to the ICOS Atmosphere Thematic Center database with extraction rights for this site, data with a shorter timestep (minute data) can be extracted directly from the ICOS database and averaged on a 30 minute window to match the highest resolution for the radon data. By default, the code applies the RTM equation for the data between 21:00 to 06:00 UTC, which is a suitable window for central Europe where most of the ICOS stations are located, but this window can be modified to fit with other latitudes or longitudes for example to accommodate the shorter summer nights in northern Europe. The length of the window can be modified as well, for example to reproduce the tests from Levin et al. (2021). We apply an orthogonal distance regression using the SciPy.odr package.No other criteria are applied initially but the correlation coefficient, the error in the linear regression, the number of data points and hours available for the calculation, the radon accumulation level and whether the radon rise stopped before 08:00 UTC are recorded so the data can be filtered in a second step. PY - 2025 PB - ICOS ERIC - Carbon Portal ER -