Skimming the Trees






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Debate over global warming is a daily news headline, but today’s climate models are hampered by limited field observation data. Duke environmental engineering Professor Roni Avissar was the first to realize the potential of helicopters in climate research by overcoming a misconception that the aerodynamics of helicopters in flight would unavoidably interfere with the climate sensors’ ability to make accurate measurements.




Did you know?

Global Climate Models are computer-driven models for weather forecasting, understanding climate and projecting climate change.

While other forms of aircraft have been employed in atmospheric research for some time, the helicopter provides an advantage due to its ability to fly very close to the ground surface--literally skimming the treetops. It can therefore bridge a gap that exists in the information about climate conditions at the ground and those obtained by airplanes at higher altitudes. By providing a vast amount of climate observation data, helicopters could enable future advances in climate models, ultimately increasing the accuracy of everyday weather forecasting and providing a more precise view of the causes and consequences of global climate change.

Avissar flew Duke’s Helicopter Observation Platform (HOP) bedecked with an atmosphere-sensing nose in two missions in the spring and summer. The first mission, funded by the National Center for Atmospheric Research, aimed to better characterize turbulence--the eddying motion of the atmosphere--over the ground surface in relation to tree cover, in particular examining how atmospheric properties change as trees leaf out over the course of the spring season and into the summer.

In the second mission, at three sites over Oklahoma, the Duke helicopter flew in unison with seven other airplanes and satellites to capture a detailed view of the atmosphere over agricultural and forested land there. The Department of Energy-led mission represented the largest concerted effort to observe the atmosphere--all the way from the ground to outer space--that had ever been attempted.

More information:

News release: Atmosphere-Sensing Helicopter Missions Bridge the Climate Forecasting Gap

Roni Avissar: http://www.cee.duke.edu/faculty/avissar/index.php

National Center for Atmospheric Research: http://www.ncar.ucar.edu/

Department of Energy: http://www.energy.gov/