The launch is Tuesday from the Kennedy Space Center in Florida. The instrument was designed and built here years ago and then transported to the US. This is a public-private partnership between space organization SRON, the Dutch branch of Airbus and research institution TNO. NASA is also involved.
The particles, called particulate matter or aerosols, are still a small but important unknown factor in climate science. They have a cooling effect because they reflect sunlight back into space. They also influence the formation of clouds, which causes even more cooling. But the magnitude of these effects is still largely unknown.
To make matters even more complicated, aerosols can also absorb sunlight themselves, making climate change worse. Climate scientists would like to know much more about it, in order to be able to determine more accurately how quickly and by how much the Earth will continue to warm.
The particulate matter can have a natural origin, in the form of sea salt or desert dust. But it is also released by human activities, such as in industry or traffic. This concerns, for example, soot and ash.
“It will be important to be able to distinguish between the different sources of aerosols,” says Otto Hasekamp, research leader at SPEXone and who works at the SRON space organization. “Is it particulate matter from sea salt, smoke from forest fires, industry or desert dust, for example.”
The new instrument can be used to measure how many of each species exist in space. “Whether something comes from sea salt or from pollution by industry is certainly important to know,” Hasekamp explains. “Because you can do something about one thing, but not the other.”
Construction of the instrument started in 2017. And thinking about it even started before 2010, he says. The development of the technology has also continued to progress step by step. “It is difficult to measure the particles, because they come in all shapes and sizes. This requires a complex instrument.”
In 2011, NASA attempted to launch such an instrument into space itself. But that launch failed, says Hasekamp. As a result, he is looking forward to next Tuesday with great anticipation, even though launches usually go well these days.
The collaboration between the various companies and research institutions in the creation of the measuring instrument was special, says Wencke van der Meulen of Airbus in Leiden. “The experts from SRON and Airbus worked in one team to develop SPEXone. The teamwork with NASA was also exceptional. They really sat next to us, which made it easy to find solutions to problems faster.”
It has been known for years that aerosols influence the climate. In recent decades, the air has become cleaner, especially in Europe, due to measures against air pollution. This is good for public health, but has the negative side effect of increasing global warming.
As a result, there are fewer dust particles floating in the air that cool the earth. This effect is in addition to the warming caused by greenhouse gas emissions. According to the latest report from the UN climate panel IPCC, without aerosols the Earth would have warmed up more, mainly due to emissions of CO2 and methane, than is currently the case.
Aerosols are one of the major uncertainties that remain about future global warming. But it is certain that they have an influence. It could also be volcanic ash. For example, the 1991 eruption of the Pinatubo volcano cooled global temperatures by about half a degree. It was a temporary effect, which disappeared a few years later.
SPEX-one is not the only instrument on PACE. Another device will determine the color of ocean water. That color says something about phytoplankton: micro-organisms floating in the water that get their energy from sunlight. Phytoplankton is an important source of oxygen in the atmosphere, and that is why scientists also want to know how it is doing.