Aerosols Attract Climate Scientists to the Arabian Desert

ABU DHABI, United Arab Emirates, August 19, 2004 (ENS) - Scientists from 22 institutions around the world are gathered in the Arabian Desert to study tiny airborne particles called aerosols and their effect on weather and climate.

Scientists from the United States are collaborating with researchers from the United Arab Emirates Department of Water Resources Studies as well as European and South African research laboratories to unravel the complex processes controlling the area's climate.

The United Arab Emirates Unified Aerosol Experiment (UAE2) mission started on August 5 and will continue through September 30. Scientists are using satellites, computer models and ground stations to understand the unique "mixing bowl" of desert dust, smoke and other aerosols created by the complex atmospheric circulations.

The Gulf and the Arabian Desert (Photo courtesy NASA Goddard Space Flight Center)

Aerosols have puzzled scientists attempting to learn how Earth's climate works. Lighter aerosols reflect heat and sunlight and have cooling properties. Darker aerosols absorb heat and light, warming the atmosphere.

UAE2's mission will measure aerosol properties, where aerosols move, and whether they add or remove warmth. Scientists also hope to model and explain complicated weather patterns in the coastal regions of the Arabian, or Persian, Gulf and the Gulf of Oman.

Recent reports and satellite data show that the Gulf region is one of the largest confluences of aerosol types in the world. Emissions, smoke transported from the Indian subcontinent, and natural dust episodes result in a unique aerosol laboratory," said Hal Maring of NASA Headquarters, Washington, DC.

The Gulf also has a complex meteorology which include variable sea surface temperatures, latent heat fluxes, strong land sea gradients, and strong mesoscale circulations. These factors combined make the Gulf a challenge to computer models and satellite sensors carrying out environmental monitoring.

A surface temperature map of the Gulf and desert as recorded by NASA's MODIS Rapid Response System aboard the Aqua satellite (Photo courtesy NASA)

"We have the most intensely monitored remote-sensing aerosol network ever assembled, including two radiation and aerosol super sites, 10 satellite instruments, six computer models, a research aircraft and a research vessel," said Jeff Reid, mission scientist from the U.S. Naval Research Laboratory in Monterey, California.

"There are 70 scientists participating, 40 of them working in the field, from over a dozen institutions, including the large South African and Colorado based National Center for Atmospheric Research weather modification teams," Reid said.

The ultimate goals of the UAE2 campaign are to:

• evaluate and improve the suite of satellite aerosol and ocean products frequently used by the scientific community in this region of the world
  
• determine the fundamental microphysical, optical and transport properties of aerosol properties in this region
  
• understand how aerosol particles interact with the regional radiation budget in bright surfaced locations
  
• to model and explain the complicated flow patterns in the costal regions of the Arabian Gulf and the Gulf of Oman.

Piotr Flatau, a research scientist at Scripps Institution of Oceanography, who will be working with Krzysztof Markowicz and others from Warsaw University during the project, said, "This project will complement Scripps' effort to understand climate change in this region of the world."

Using the Naval Research Lab's Mobile Atmospheric Aerosol and Radiation Characterization Observatory, scientists from the Scripps Institution of Oceanography and Poland's Warsaw University will study the impact of aerosols and clouds on incoming solar radiation and the hydrologic cycle and energy balance in this mostly rain-free area.

"I know the Arabian Sea from research cruises during the Indian Ocean Experiment (INDOEX), but the UAE2 experiment brings a new set of challenges," Flatau said. "While INDOEX took place in a mostly monsoonal region, the UAE is dry and hot. The temperatures are reaching 40 degrees Celsius (104 F) there right now and we do not expect much rain."

By obtaining more accurate data about aerosols and their behavior, scientists will improve computer climate models and predictions of climate behavior in response to changes in aerosol concentrations.