Recently, China's first terrestrial ecosystem carbon monitoring satellite " Jumang " was successfully launched. This satellite was called the "carbon sink king" in space by the media. Many people are curious as to why satellites can help achieve the “double carbon” goal?
Generally speaking, satellites can help achieve the "double carbon" goal in two ways:
The first is satellites that help monitor carbon emissions, which can be called carbon source satellites. To achieve the quantitative emission reduction goals of “measurable, reportable, and verifiable”, needs practical measurement methods and technologies that are very important. In April this year, China launched the atmospheric environment monitoring satellite "Atmos-1" with carbon dioxide laser detection capabilities. According to media reports, when this active lidar satellite is working, it will emit lasers of different bands to the ground in real time, and receive the reflected laser echo signals that have been dissipated by the gas. Through these echo signals that are dissipated to varying degrees, information such as the carbon dioxide concentration in the global atmosphere can be retrieved, so as to accurately monitor the current status and changes of carbon sources.
The second type is satellites that monitor carbon sinks. carbon sink and carbon source are relative concepts. For example, forests can absorb and store carbon dioxide in the atmosphere, just like a super-large "carbon fixation" factory, which is the process of fixing carbon dioxide free in the air. It's called a carbon sink. Obtaining high-precision vegetation height and area information is the key to forest carbon sink monitoring.
According to media reports, the main function of the "Jumang" satellite is to calculate carbon sinks. It is equipped with lidar . The satellite emits laser to the ground, calculates the time difference between the laser and the tree crown and the ground, and combines the speed of light and other prior knowledge to calculate the height of the tree. In addition, through multi-angle multispectral cameras, different spectra reflected by different trees are collected. By combining the information of angles and spectral segments, the density of the forest and the type of vegetation can be known, and the density of the forest can be accurately restored. Different types of vegetation in have different carbon sink values.
Whether it is monitoring carbon sources or carbon sinks, it essentially uses the principle of remote sensing satellite .
In fact, using aerospace technology to monitor the surface and the earth's atmospheric environment is not a new technology that has only appeared in recent years. In 1960, the United States launched its first man-made experimental weather satellite, kicking off atmospheric monitoring. China's development of meteorological satellite began in the 1970s. In 1988, China launched its first meteorological satellite, "Fengyun-1", a sun-synchronous orbiting meteorological satellite. To date, it has successfully launched 19 Fengyun series satellites.
With the development of technology, various meteorological remote sensing instruments carried by meteorological satellites have gradually become more abundant. Various detection loads can detect visible light, infrared and microwave radiation and other information of the earth and atmosphere, and convert them into digital information and send it back to the ground. After calculation and processing, various meteorological information data are obtained.
With global warming , greenhouse gases carbon emission issues have been paid attention to, and the function of meteorological satellites to monitor gases has been valued. In 2009, Japan launched the greenhouse gas observation satellite "Breath", and in 2014 the United States launched the "Orbiting Carbon Observer 2". In 2016, China’s independently developed carbon monitoring satellite was also successfully launched.
Compared with other ground means, aerospace technology represented by satellites has three main advantages in monitoring relevant data: First, satellites fly high and can see far, and can measure data that is difficult to measure by ground means. Second, satellites can see faster and more efficiently, and can see multiple data such as vegetation height, vegetation area, chlorophyll fluorescence, atmospheric PM2.5 content, and carbon dioxide at once.Third, satellites can conduct efficient detection on a global scale, making carbon data transparent and becoming an important indicator in international negotiations and an effective basis for formulating policies, increasing the voice of international carbon negotiations.
Currently, China’s space-based carbon monitoring system is under planning and systematic demonstration. Through the development of various types of multi-scale and multi-dimensional satellite systems, phased deployment and network operation, it will help to collaboratively serve the overall goal of “double carbon”.
Source / "Global" magazine
Author of the article: Xu Ming, founder, chairman and CEO of Galaxy Aerospace
Editor / Yang Zhen
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