China's carbon dioxide monitoring satellite TanSat has produced its first batch of human-caused carbon dioxide emission (CO2) signatures, offering a scientific basis for the country's efforts to combat global warming.

The space-based monitor detected carbon emissions from human activities based on TanSat's CO2 observations together with nitrogen dioxide (NO2) measurements from the European satellite Copernicus Sentinel-5 Precursor, according to a study published Tuesday in the journal Advances in Atmospheric Sciences.

TanSat, launched in 2016, is China's first global carbon dioxide monitoring satellite, with "Tan" standing for "carbon" in Chinese.

The 620-kg satellite TanSat, sent into a sun-synchronous orbit about 700 kilometers above Earth, is monitoring the CO2 concentration, distribution and flow in the atmosphere. Recently, new algorithms were uploaded onto the TanSat devices to greatly improve its measurement precision.

An international team of Chinese and Finnish researchers used TanSat data captured in May 2018 near the northern Chinese city of Tangshan and in March 2018 near Tokyo. They compared the captured data to nitrogen dioxide measurements on the same dates over the same cities, according to the study.

The CO2-to-NO2 ratios in Tangshan and Tokyo were found to align with the emission inventories, "an important step in TanSat data analysis," said Janne Hakkarainen, the paper's co-author.

"The next step is to infer emissions and to prepare for the TanSat-2 constellation including the joint analysis of CO2 and NO2 plumes," said Hakkarainen, who had worked with the Finnish Meteorological Institute.

TanSat is China's first CO2 monitoring mission to conduct research on the global carbon cycle. The new generation of TanSat mission, TanSat-2, is now in the design phase, said the paper's co-author Liu Yi, an Institute of Atmospheric Physics (IAP) researcher.

TanSat-2 is a constellation of satellites distributed into at least two orbits in the morning and afternoon to cover a city or a point source twice a day.

It is expected to be used to monitor cities with an 800 to 1,000-kilometer-wide swath to record the gradient of carbon dioxide from the city's central region to rural areas, and it will use a 500-meter footprint size to improve the emission estimation accuracy, Liu noted.

"Our goal is to use satellite measurements to improve our knowledge of the carbon cycle and to further analyze and constraint the carbon dioxide sources and sinks and their uncertainties," Liu said.

(With input from Xinhua)