A technician at the Dryden Aircraft Operations Facility in Palmdale, Calif., checks out an instrument mounted in the belly of NASA's DC-8 flying laboratory prior to its departure in January for the GCPEx field campaign to measure falling snow. › View Larger Image
NASA's DC-8 airborne science laboratory has completed 10 data-collection flights in support of NASA's Global Precipitation Measurement Cold-season Precipitation Experiment, or GCPEx, snow study over Ontario, Canada. The latest mission occurred the afternoon of Feb. 16, a 4.5-hour flight over a storm system that produced light snowfall over the target area with good data collected by the two primary instruments being used on this experiment, the APR-2 Airborne Precipitation Radar and the Conical Scanning Millimeter-wave Imaging Radiometer, or CoSMIR.
A prior flight Feb. 12 met with less success, as light snow showers dissipated during an evening mission and the flying laboratory and its team of scientists returned to their deployment base in Bangor, Maine after 3 ½ hours in the air.
Three GCPEx precipitation sensors are surrounded by a small amount of snow at the Environment Centre for Atmospheric Research Experiments in Egbert, Ontario, Canada. Sensors left to right are the ADMIRARI passive microwave radiometer from the University of Bonn, Germany, NASA's Dual-frequency Dual-polarization Doppler Radar (D3R), and the Deep Processor Radar from the University of Cologne, Germany. (NASA / Gail Skofronick-Jackson) › View Larger Image However, a more than seven-hour night flight Feb. 11 was flown over the Environment Centre for Atmospheric Research Experiments, or CARE, location in Egbert, Ontario, where snow conditions were excellent. In addition to the DC-8, the NASA-funded University of North Dakota's Cessna Citation and the Canadian National Research Council's Convair 580 were also in the air on the coordinated mission.
The GCPEx field experiment will help scientists match measurements of snow in the air and on the ground with measurements to be taken by the Global Precipitation Measurement satellite, due tolaunch in 2014.
"We are looking at the precipitation and the physics of precipitation, such as snowflake types, sizes, shapes, numbers and water content," said Walter Petersen, the GPM ground validation scientist at NASA's Wallops Flight Facility in Virginia. "These properties affect both how we interpret and improve our measurements."
In addition to the CARE ground network of snow gauges and sensors and measurements from aircraft, advanced ground radars will scan the entire air column from the clouds to the Earth's surface.
During GCPEx, the DC-8 is flying above the clouds while the Citation and the Convair 580 fly through the clouds while their specialized meteorological instruments measure the microphysical properties of the raindrops and snowflakes inside.
If the opportunity exists during the mission, now scheduled to end Feb. 29, the DC-8 also will fly over blizzards along the northeastern United States.
For more information about GCPEx, visit: