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Global remote sensing of greenhouse gases ramps up

11 May 2023

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With growing pressure to reduce the amount of greenhouse gases released into the atmosphere, recent research studies using the carbon dioxide monitoring TanSat mission are timely.

TanSat is an ESA Third Party Mission (TPM), managed by the ministry of Science and Technology of China (MOST), with the objective to detect and monitor atmospheric carbon dioxide.

TanSat data help improve global carbon budget estimates
TanSat data help improve global carbon budget estimates

A research paper published earlier this year in the journal of Advances in Atmospheric Sciences, detailed the first attempt to use TanSat measurements to detect anthropogenic carbon dioxide emission signatures.

The research team used carbon dioxide observations from TanSat together with nitrogen dioxide measurements from the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Copernicus Sentinel-5 Precursor (S5P) satellite, over two study areas in Tangshan, China and Tokyo, Japan.

Results show that TanSat carbon dioxide measurements have the capability to capture the anthropogenic variations in the plume and have spatial patterns similar to that of the TROPOMI nitrogen dioxide observations.

Carbon dioxide enhancements of 2–3 parts per million in Tokyo and 3–4 parts per million in Tangshan have been observed by TanSat nadir measurements, corresponding to enhancements in the Sentinel-5P nitrogen dioxide measurement.

The TanSat mission launched in 2016 and its data are available from March 2017 to September 2018 (with cloud/aerosol data provided until 2020). It is funded by MOST (Ministry of Science and Technology) of China and will soon be succeeded by the next generation TanSat-2 mission, which will focus on global carbon dioxide monitoring (“Tan” means carbon in Chinese).

Data from TanSat are included in ESA’s prestigious Earthnet TPM programme and Climate Change Initiative Plus (CCI+), following the 2020 protocol between National Remote Sensing Centre of China (NRSCC) and ESA, under the Dragon programme.

In reciprocation, ESA would provide data from Copernicus Sentinel-5P and the upcoming Earth Explorer – FLEX – via China’s GEOSS Data sharing network. Both parties also agreed to provide cooperation with respect to calibration and validation, which is coordinated via regular workshops.

A research paper published in the Journal of Remote Sensing, summarises the results of a collaborative project between European and Chinese teams to characterise and evaluate the datasets from the TanSat mission by retrieval intercomparisons and ground-based validation.

The research applies model comparisons and surface flux inversion methods to TanSat and other carbon dioxide missions, with a focus on China.

Seasonal maps of the TanSat v2 dataset using the IAPCAS retrieval algorithm
Seasonal maps of the TanSat v2 dataset using the IAPCAS retrieval algorithm

While the first TanSat global maps of carbon dioxide dry air mixing ratio measurements (XCO2) over land have been released, recent improvements in retrieval algorithms have resulted in a new TanSat global XCO2 product. The new product improves the accuracy and retrieval, providing opportunity for future applications in global carbon flux studies.

Dr. Dongxu Yang from the Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, and Dr. Sisi Wang, NRSCC spokesperson for ESA’s GHG Co-operation with NRSCC, say, “Monitoring the carbon dioxide released into our atmosphere is of global interest. However, one mission alone cannot provide enough data for carbon flux research, so it’s important to cooperate around remote sensing data for greenhouse gas monitoring. The research we have done using TanSat data, will provide a good basis for future carbon dioxide monitoring missions.”

Being developed by ESA on behalf of the EU, the new Copernicus Anthropogenic Carbon Dioxide Monitoring mission, or CO2M for short, is destined to be Europe’s prime mission for monitoring and tracking carbon dioxide emissions from human activity.

As the international community endeavour to tackle the global climate crisis, acquiring data about greenhouse gas emissions is critical. ESA disseminates data from TanSat via the TPM programme and data can be accessed here for free for research and application development purposes.



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