Radar System Vital to Cloud StudyNASA'S AIRBORNE CLOUD RADAR HAS BEEN IN the sky aboard a NASA DC-8 in an effort to better understand clouds—how they affect our environment and our quality of life. This Airborne Cloud Radar flight series, expected to total 20 flight hours, is designed to test several hypotheses and techniques related to satellite remote sensing of extensive, long-lasting, nonprecipitating layers of cloud in the middle and upper troposphere up to seven miles from Earth's surface. Cloud studies provide scientists the most detailed information to date on the processes of powerful storms, leading to new insights on how they affect global climate patterns and to improved forecasting that saves lives and money. Studying cloud structures can help in forecasting global climate patterns, not just in the near future but in many years ahead. This will prove beneficial in predicting floods, droughts or above- or below-average temperatures. All of these can have positive effects on the quality of life on Earth—rendering potential life savings, preventing cost increases, maintaining productivity and avoiding a negative economic effect. It can translate into stock pile upkeep, city planning, staff advanced planning and sport and entertainment activity schedules. "Clouds represent a scientific puzzle that researchers have been trying to piece together for centuries," said Dr. Fuk Li, the principal investigator for the cloud radar at NASA's Jet Propulsion Laboratory in Pasadena, California. "Scientists still don't know very much about the internal, vertical structures of clouds, and that leads to uncertainties in weather and climate predictions," he said. "Using the cloud radar, we will be able to study clouds in a new way that will help us understand their structure like never before. Once we have the cloud vertical structure information, atmospheric scientists will have a much better handle on long-term predictions of weather and climate change." Scientists will compare these data with measurements taken by satellite and ground-based sensors, including the Department of Energy's Southern Great Plains Cloud and Radiation Testbed. Known by the acronym CART, this testbed is a series of instruments spread across north central Oklahoma and south central Kansas. The cloud radar experiment was installed in the tail area (looking downward) of the DC-8 at NASA's Dryden Flight Research Center in Edwards, California. The DC-8 then flew to Tinker Air Force Base near Oklahoma City, Oklahoma, the origination point of this series of missions in which the radar collects cloud data while the plane flies above the clouds. The radar, taking vertical measurements of the clouds from above, operates at 94 gigahertz, making it sensitive to cloud particles. The instrument transmits radar energy, which bounces off the cloud particles and is reflected back toward the aircraft. The radar measurements will be combined with information provided by other sensors to help analyze the properties of the clouds observed. "The DC-8 was selected because it is the only aircraft that is capable of this mission in terms of altitude, speed, range and capacity for carrying scientists onboard. Since scientists can fly on the aircraft, they can operate their experiments themselves," said DC-8 mission manager Chris Jennison of Dryden. The Jet Propulsion Laboratory developed the Airborne Cloud Radar in conjunction with the University of Massachusetts at Amherst; Colorado State University in Ft. Collins; and the University of Pennsylvania in Philadelphia. For more information, contact Dr. Fuk Li at the Jet Propulsion
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