1. Work Package 2 – Overview of instrumentation, data gathering and calibration issues Lidar Calibration Ewan O’Connor, Anthony Illingworth and Robin Hogan Progress meeting 3 –Reading – 24-25 Oct 2002

2. Calibration technique  ’=1/2  k Use Mie theory for spherical droplets. k is constant for cloud droplets (D=8-30  m).

3. Multiple scattering Calculate  as a function of range using Eloranta’s model (1998). Need to know laser divergence and telescope FOV.

4. Aerosol k in aerosol variable  therefore extinction unknown  effect on calibration unknown Current solution: Reject profile for calibration if  a > than some predetermined value

5. Validation – UV Raman lidar Calibrate UV Raman lidar with molecular backscatter. To validate – need to calculate atmospheric transmission at both wavelengths and the value of  for each instrument.

6. Validation – UV Raman lidar Calibrate UV Raman lidarCompare calibrated CT75K ceilometer

7. Validation – UV Raman lidar Step 1. Calibrate both lidars Step 2. Adjust for differences in atmospheric transmission Step 3. Adjust for differences in multiple scattering

8. Validation in space – LITE

9. CT75K – solar background