Newsletter

Analyze the “light” emitted by the earth: NASA’s challenge to find clues for the realization of a carbon-free society | WIRED.jp

The sand smoke swirled up in the Sahara Desert does not stay there. In the vast deserts of the African Continent, sand smoke is constantly swirling. The dust flies to Europe, turning the top of a snow-covered mountain orange. On the other hand, it may cross the Atlantic Ocean to deliver nutrient phosphorus to the Amazon rainforest, or it may reach the United States.

However, all of the sand smoke emitted from the Sahara Desert and other desert areas cannot be well explained by existing climate models. It is possible with satellites to track sand smoke moving through the atmosphere. But scientists don’t have enough data to definitively show how sand smoke raises or lowers the Earth’s temperature, whether it’s accelerating or slowing the climate change that humanity is causing. That is.

Analyzing the climate with the “light” emitted by the earth

“We have a set of data consisting of 5,000 soil samples, but that’s not enough,” says Natalie Mahwald, who studies the Earth system at Cornell University. “No one wants to go to the middle of the desert to find out the nature of the soil.”

So Mahwald is working with NASA’s mission, Earth Surface Mineral Dust Source Investigation (EMIT). The equipment used in this mission will be launched on the International Space Station (ISS) during June 2022[Note: Scheduled for June 28, US time].

The equipment used by EMIT uses spectroscopy technology. Astronomers have applied this powerful technique over the past few decades to determine the composition of distant objects. This time, by pointing this to the earth, it is said that the land will be analyzed.

This mission will finally give scientists a complete picture of the sources of sand smoke and the impact of these particles on climate. “It makes much more sense to analyze from a distant universe than to go to the middle of the desert,” says Mahwald.

Every molecule contained in a substance absorbs and emits electromagnetic waves in a unique way. This allows astronomers to use spectroscopes to analyze light coming from distant planets and identify each element’s characteristics, such as hydrogen and carbon.

The target planet may be far away. Still, the light coming from the planet reveals the composition of the atmosphere. This is like taking a fingerprint without touching the other person.

The influence of the flow of sand smoke can be seen

The EMIT spectrometer will be mounted at the bottom of the ISS and will capture the Earth’s spectrum 50 miles wide to capture the characteristics of certain minerals. For example, even if the surface of one desert area and another desert area look the same to the human eye, iron oxide and clay can be distinguished by passing through a spectroscope.

“We need to get the” fingerprints “of minerals in the arid areas,” said Robert O. Green, a senior investigator at EMIT and a researcher at NASA’s Jet Propulsion Laboratory (JPL). “Within a year, we will be able to create a mineral resource map of the arid zone. This resource map can be used to renew the climate model.”

Combining new data with existing models will give climate scientists a better understanding of how sand smoke works at global temperatures. Until now, researchers have simply referred to sand smoke as “yellow sand.” “But if you look at the soil, there are many different colors, such as black, red, and white, which is very reflective,” says Mahowald, EMIT’s Deputy Principal Researcher. “Dark colors absorb more electromagnetic waves to warm us, and bright colors reflect electromagnetic waves to cool us.”