Analysis of Multiple Wavelength Lidar Backscatter From Cirrus
Abstract
Lidar backscatter from cirrus cloud particles at multiple wavelengths (532 nm, 1064 nm, 10591 nm) was measured at Hanscom AFB, MA in August 2001. Range-resolved measurements were made for several hours daily at altitudes from 9 km to 16 km over a temperature range of -30C to -70C. Three days were selected for study -- 9 August, 14 August, and 16 August 2001. Cirrus backscatter measurements were analyzed in combination with scattering theory for ice spheres and long ice cylinders to better understand their behavior. For 532 nm and 1064 nm, the logarithm (base 10) of backscatter magnitudes (/m-sr) ranged from 4.5 to -6.0 within the cloud area while backscatter magnitudes for 10591 nm ranged from -6.5 to -8.5. Agreement existed between the range of measured backscatter wavelength ratio magnitudes and those computed from scattering theory but no consistent information was discerned concerning modal particle sizes. Calculations of cirrus ice water content, exinction-to- backscatter ratio, and optical depth yielded magnitudes consistent with published values for in-situ and remote measurements.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2003
- Accession Number
- ADA417201
Entities
People
- John R. Roadcap
- Patrick J. Mcnicholl
- Phan D. Dao
Organizations
- Boston College