For the first time, a space mission will be responsible accurately determine the composition of minerals It is contained in fog and spreads over great distances by wind from the Sahara Desert. In this way, the extent of the threat posed by these particles and the effects of this phenomenon on climate and ecosystems will be better understood.
Windblown between continents and oceans, this dust does more than just cloudy skies, clogs the lungs and leaves an unpleasant dirty film on windshields. It can also affect the weather, accelerate melting, and fertilize plants on land and in the ocean. Particles from North Africa can travel thousands of kilometers around the world, cause phytoplankton explosions, feed the Amazon rainforest with nutrients, and cover many cities with a blanket of sand as they absorb and scatter sunlight.
NASA’s Earth’s Surface Mineral Dust Resource Survey (EMIT) mission due to launch in JuneIt aims to deepen researchers’ understanding of these fine particles of soil, silt and clay from Earth’s deserts and how they ultimately affect climate.
Darker, iron-rich dust absorbs heat from the Sun and warms the surrounding air, while lighter-colored, clay-rich particles do the opposite. “Different types of dust have different properties (can be acidic, basic, light colored, dark…) and determine how particles interact with Earth’s atmosphere as well as soil, water and organisms,” said Robert O. Green at EMIT principal investigator.
It is not known whether it cools or warms the air.
Using EMIT data, he added: “We will be able to map the origin regions of dust around the world” and understand how the planet is warming and cooling, and how this may change in future climate scenarios.”
Researchers at NASA and other institutions have long focused on the movement of dust through the air, which can take hours or weeks, depending on the size of the particles. Atmospheric effects are included in climate models, but It is not clear whether this dust has a net warming or cooling effect on the planet.and how that has changed over time.
Natalie Mahowald, EMIT assistant principal investigator and an Earth systems scientist at Cornell University in Ithaca, New York, explains that the uncertainty stems from a lack of data on the composition of the dust. The researchers’ information comes from less than 5,000 sampling locations, mostly located in agricultural areas, where detailed soil information can be used for agricultural or commercial purposes.
“Normally, in climate models we model dust as yellow, which is the average color of all types of dust, but if you’ve been to a desert area before, you know that sand isn’t the same color,” Mahowald said. I said. “So the assumption that it’s uniform all over the world doesn’t reflect what’s really going on.”
Mapping the origins of dust
The EMIT mission should clarify this scenario. Installed on the International Space Station, State-of-the-art imaging spectrometer will map the world’s mineral dust resourcesThe instrument collects information about the color and composition of the particles as it orbits over dry, sparsely vegetated areas.
EMIT will focus on 10 main types of powderincluding those containing iron oxides whose deep red hues can cause strong warming of the atmosphere. Knowing what types of dust are prevalent on the surface of each region will provide new insights into the composition of particles lifted and carried by the air. With these insights, climate scientists can improve their understanding of the regional and global climate impacts of mineral dust.
“Previously, scientists have worked with individual spectrometers,” Green said. “Now we’re actually going to use 1,280 spectrometers on the Earth’s surface.each will collect hundreds of measurements per second,” he added.
EMIT will present more than a billion new measurements during its mission. Because each type of dust has a unique light-reflecting signature, researchers will be able to determine the mineral and chemical composition of substances on the surface.
The precision of these observations will make EMIT’s instrument one of the most advanced Earth-focused imaging spectrometers ever installed in space.
Reference article: https://www.nasa.gov/feature/jpl/nasa-s-emit-will-map-tiny-dust-particles-to-study-big-climate-impacts