Overview of the EMIT mission
The first space mission dedicated to precisely identifying the mineral makeup of desert dust will soon launch to reveal how particles lifted from the Sahara travel vast distances on wind currents and form hazy plumes. This mission aims to quantify the extent of the threat these particles pose and to clarify their influence on climate and ecosystems around the world.
Dust travels across continents and oceans, not just clouding skies. It can irritate lungs, leave a dusty film on windshields, and affect weather patterns. It can speed up the melting of ice and snow, while delivering nutrients to soils on land and in the sea. North African dust can traverse thousands of kilometers, triggering phytoplankton blooms, feeding the Amazon rainforest, and even coating many cities with sand as it absorbs and scatters sunlight.
NASA’s Earth Surface Mineral Dust Resource Assessment EMIT mission, planned for launch in June, seeks to deepen understandings of these fine mineral particles from deserts and to determine how they influence climate in the long run.
Dark iron-rich dust tends to absorb heat from the Sun, warming the surrounding air, while lighter clay-rich dust tends to have a cooling effect. Types of dust vary in acidity, color, and other properties, which influence how particles interact with Earth’s atmosphere as well as soils, water, and living systems, noted EMIT principal investigator Robert O. Green.
Do dust particles cool or warm the air?
With EMIT data, Green explained, scientists will map where dust originates and gain a clearer view of how the planet warms or cools and how future climate scenarios may evolve.
For years researchers have tracked dust plumes as they move through the atmosphere, often taking hours or weeks to cross regions, depending on particle size. Climate models include some atmospheric effects, but it remains unclear whether dust overall warms or cools the globe and how this balance has shifted over time.
Natalie Mahowald, EMIT’s assistant principal investigator and an Earth systems scientist at Cornell University, points to the missing data about dust composition as the root of the uncertainty. Current information comes from fewer than 5,000 sampling locations, mostly in agricultural zones used for soil insights in farming and commerce.
“In climate models, dust is often treated as a uniform yellow matter, yet desert sands vary in color and composition,” Mahowald remarked. “The assumption of uniformity does not reflect the real world.”
Tracing the origins of dust
The EMIT mission is set to change that. Installed aboard the International Space Station, the state-of-the-art imaging spectrometer will map global mineral dust resources by examining the color and composition of particles as it orbits over dry, sparsely vegetated regions.
EMIT will focus on ten main dust types, including iron oxide rich particles whose deep red hues can cause stronger atmospheric warming. Understanding which dust types dominate each region will reveal new details about the surface composition of airborne particles. Those insights will help climate scientists refine their understanding of the regional and global climate impacts of mineral dust.
“Previously, scientists relied on single spectrometers,” Green noted. “Now a network of 1,280 spectrometers on the Earth’s surface will gather hundreds of measurements every second.”
EMIT is expected to produce more than a billion new measurements during its mission. Because each dust type has a distinct light-reflection signature, researchers will be able to determine the mineral and chemical makeup of surface materials with greater precision.
The accuracy of these observations positions EMIT as one of the most advanced Earth-focused imaging spectrometers ever deployed in space.
Reference article: EMIT will map tiny dust particles to study big climate impacts, NASA feature at JPL
Citation: NASA EMIT feature, NASA