Scientists have long known that cloud droplets form on tiny, microscopic airborne particles – or aerosols. These particles allow water vapor to condense on their surfaces. Without them, cloud droplets, mist, fog or rain could not form at all. Pollution caused by human activities produces very significant amounts of additional aerosols. These airborne particles can cause substantial changes in our weather and climate. To gain better understanding of aerosols, dozens of scientists from NASA, the U.S. Navy, United Arab Emirates (UAE), and research organizations from around the world are meeting in the Arabian Desert during August and September 2004 to decipher the impact of aerosols on the region’s weather and climate.
The United Arab Emirates Unified Aerosol Experiment (UAE2) will rely on satellites, computer models, aircraft, and ground stations to understand the unique ”mixing bowl” of desert dust, smoke, and man-made emissions worsened by the region’s extraordinary meteorological conditions. Temperatures inland in UAE often exceed 122°F (50°C). Humidity over the Persian Gulf is high while away from the coast it often falls below 10%. Frequent land-sea breeze circulation also mixes air from over land and sea.
While UAE2 will measure the properties of aerosols, where they move, and help clarify whether they add or remove warmth, the mission will also help improve our measurement of aerosols from NASA’s Terra and Aqua satellites. Taken together, the ground-based, aircraft and satellite measurements will give scientists a more comprehensive data set, allowing researchers to improve computer models and understand more exactly how our climate responds to aerosols.
Satellite data will be compared to remote sensing measurements made on the ground by various instruments. The Naval Research Laboratory’s Mobile Atmospheric Aerosol and Radiation Characterization Observatory (MAARCO), NASA’s Surface-sensing Measurements for Atmospheric Radiative Transfer (SMART), and 15 Aerosol Robotic Network (AERONET) instruments will gather data about mineral dust and pollutant aerosols over land and water. UAE2 is one of many research programs involving AERONET – a ground-based aerosol monitoring network and data archive supported by NASA. AERONET provides globally distributed near real time observations of several aerosol properties.