China used advanced satellite technology to monitor Nord Stream leak
- The Gaofen-5 02 satellite provided the first accurate estimate of the leak from the suspected act of sabotage, scientists involved in the project say
- The country is currently building up its own database of carbon emissions, including methane
The Russian-built pipelines supplying natural gas to Europe were hit by a series of explosions on September 26 in a suspected act of sabotage by unknown parties.
Most greenhouse gas monitoring satellites can only measure the total emissions over vast areas, but the Chinese scientists say, without providing precise details, they can narrow the area measured significantly.
On October 1, Canadian satellite operator GHGSat released the first publicly available estimate based on satellite data collected the previous day, which showed that a ruptured spot on the pipe Nord Stream 2 was leaking gas at a rate of over 20 tonnes per hour.
But the data collected by China’s Gaofen-5 02 satellite at the same location on the same date suggested the leak could have reached 70 tonnes per hour.
In a statement posted on the website of the Chinese Academy of Sciences’ Shanghai Institute of Technical Physics on October 3, the Chinese team said they had confidence in their results.
“Accurate monitoring of methane emissions from space is an international challenge. The hyperspectral cameras on Gaofen-5 and other satellite platforms have been proven successful in precise monitoring of methane emissions many times before,” they said in the statement.
On October 5 the Canadian company said its earlier figures had underestimated the leak and updated the figure to 79 tonnes per hour.
The Gaofen 5-02 satellite, which was launched in September last year, has ultra-sensitive infrared sensors that can trace a cloud of methane gas in the atmosphere to its origin.
Methane gas absorbs part of the sunlight in the infrared range, but the change in the light spectrum is so small that most existing infrared detectors cannot pick up the signal from orbit.
The satellite was hailed by the China Association of Remote Sensing Applications as a major breakthrough in remote sensing technology because other countries could not detect or measure methane emissions with such a high accuracy.
China has a growing interest in climate data and has previously expressed concern that climate change models and United Nations assessments are mostly built on data sets produced by Western countries that may be skewed in their favour – potentially hampering China’s development unfairly.
In 2018, Chinese Academy of Sciences vice-president Ding Zhongli told the Communist Party mouthpiece People’s Daily that whoever had the scientific data would have the initiative in international negotiations on emissions targets.
“To a certain extent, the right to carbon emissions is equal to the right to development ... In the game of international negotiation, we use scientific data to speak,” he said.
The infrared technology used in methane detection could also find applications in surveillance for military targets, according to a paper by researchers involved in the development of the Gaofen-5 02 satellite published in July in the domestic peer-reviewed journal Infrared and Laser Engineering.