News Archive

posted 05/16/03

Columbia-Led Scientists Dust Off Desert Sands From The French Alps

Dust Storm over China's Taklimakan Deser

Dust storm over China's Taklimakan Desert, on April 14, 2002, from the MODIS Instrument on NASA's Terra Satellite.

NASA-funded scientists using an atmospheric computer model proved for the first time that dust from the Takla-Makan desert of China traveled more than 12,400 miles (20,000 kilometers) over two weeks time and landed atop the French Alps. Chinese dust plumes have been known to reach North America and even Greenland, but have never been reported before in Europe.

These findings were highlighted in a paper authored by Francis E. Grousset of the Lamont-Doherty Earth Observatory of Columbia University (LDEO), Palisades, N.Y., and Université Bordeaux, France; Aloys Bory and Pierre E. Biscaye, also of LDEO, and Paul Ginoux, GEST, University of Maryland, Baltimore County (UMBC) and NASA’s Goddard Space Flight Center, Greenbelt, Md. The study appeared in a recent issue of the American Geophysical Union’s Geophysical Research Letters.

This study looked at dust that traveled the globe from February 25 to March 7, 1990. “The dust particles traveled around the world in about two weeks, and along their journey, crossed China, the North Pacific, North America and the North Atlantic Ocean,” Ginoux said.

Research conducted in 1994 showed that over the 20 years prior, a score of red dust events coated the snow cover in the Alps and Pyrénées mountains. The red dust that topped these European mountain ranges was sampled and stored in bags for comparison with dust from other parts of the world. Scientists analyze the minerals and compositions of certain distinctive elements (isotopes) of the dust to identify where it came from.

Grousset and colleagues found two examples of dust collected in southern France that clearly originated from North African sources because of the dust’s color and composition.
The dust's
        13+ day trip from the Takla-Makan desert in China,
        circling the world and landing in the French

A DUSTY PATH FROM CHINA TO FRANCE -- The spiked line shows the dust's 315 hour (13+ days) trip from the Takla-Makan desert in China, circling the world (counterclockwise) and landing in the French Alps on March 6, 1990. The black star is where scientists gathered samples.

The origins and final locations of dust are important to help determine any effects from heavy metal, fungal, bacterial and viral pollution that may be associated with it. Previous studies indicated that fungi found in African dust caused Sea Fan disease in Mediterranean coral reefs. The National Institute of Health’s National Institute of Allergy and Infectious Diseases identified airborne dust as the primary source of allergic stress worldwide.

Ginoux and his colleagues utilized some of NASA’s technology and support in their research. Meteorological information such as wind speed and direction, precipitation, air pressure, and temperature were input in a computer model that recreated how the atmosphere moved during the time that the dust moved from China to the Alps. That meteorological information was taken from the NASA Goddard Earth Observing System Data Assimilation System (GEOS DAS).

Several computer models simulating the movement of the dust in the atmosphere were used to track its journey around the globe. The Global Ozone Chemistry Aerosol Radiation Transport (GOCART) computer model, largely funded by NASA, uses the winds, soil moisture, and surface characteristics to simulate the dust generation and transport. The National Oceanic and Atmospheric Administration’s (NOAA) Air Resources Laboratory (ARL) showed the paths of air masses as they moved around the world from the time the dust was swept into the atmosphere to the time it settled on the mountaintops.

NOAA’s ARL can project where air pollution will move based on meteorological conditions. NOAA’s National Center for Environmental Prediction re-analyzed meteorological conditions around the globe, and also plotted the dust movement to verify the computer models.

GOCART MODEL'S DUST PATH: 2-25-90 to 3-7-90 -- This time series of dust movement was generated from the GOCART model, and the NOAA NCEP projection is depicted by the thick black line. It shows movement from China to the French Alps projected as moving in the air almost 2 miles above sea-level.

This work was funded by the National Center for Scientific Research (CNRS) in France, NASA’s Earth Science Enterprise (ESE), and the National Science Foundation. NASA's ESE is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather and natural hazards using the unique vantage point of space.

The Lamont-Doherty Earth Observatory, a member of The Earth Institute at Columbia University, is one of the world’s leading research centers examining the planet from its core to its atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, environmental hazards and beyond, Observatory scientists provide the basic knowledge of Earth systems to inform the future health and habitability of our planet.

The Earth Institute at Columbia University is among the world’s leading academic centers for the integrated study of Earth, its environment, and society. The Earth Institute builds upon excellence in the core disciplines—earth sciences, biological sciences, engineering sciences, social sciences and health sciences—and stresses cross-disciplinary approaches to complex problems. Through its research, training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world’s poor.