1. Kenneth H. Underwood Atmospheric Systems Corporation Santa Clarita, CA NAQC 2011 San Diego1

2. Background What is a SoDAR? Acoustic wind profiling instrument How does it work? Receives the atmosphere echo from a pulse of acoustic energy traveling away from its source What are the data products? Wind and turbulence profiles Local mixing heights Applications Transport and dispersion of pollution, particles, etc. “Virtual” instrument tower of wind instruments NAQC 2011 San Diego2

3. SoDAR data example NAQC 2011 San Diego3

4. 4 System Geometries Monostatic Emitter / receptor are the same (or a closely spaced) speaker or set of speakers Bistatic Emitter and receptor speaker (or speakers) are separated at a distance.

5. Brief History of SoDAR Technology 1970-1985 Monostatic and Bistatic geometry 1985- 1991 Phased array of speakers, monostatic geometry 1991-2010 High frequency, low altitude, monostatic geometry 2010-2011 Bistatic geometry reborn ?? NAQC 2011 San Diego5

6. 6 Atmospheric echo components Change of Monostatic and additional Bistatic echo efficiency in altitude. Atmospheric echo “efficiency” is related to local atmospheric turbulence.

7. Bistatic signal improvement (4500 Hz) NAQC 2011 San Diego7

8. Summary Bi-static SoDAR geometry One of original geometries explored (1970s) Common volume sampling, 3D measurement with each pulse Higher data recovery expected due to higher signal level Minimum influence on and by the ambient acoustic environment Applications Wind energy Ambient wind and inversion monitoring Urban monitoring of free atmospheric flows Airport operations Cost effective (value/purchase price) instrument NAQC 2011 San Diego8