Visibility and Vertical Structure Measurements in Southern Germany.
Interim rept. no. 2, 21 Dec 82-21 Mar 83,
FRAUNHOFER-INST FUER ATMOSPHAERISCHE UMWELTFORSCHUNG GARMISCH-PARTENKIRCHEN (GERMANY F R)
Pagination or Media Count:
In the 1st Interim Report it was mentioned that the sensitivity of the PIN diode detector for the 694 and 1060 nm wavelengths is too high for the measurement of lidar returns from close-range fog or clouds. In the meantime two neutral density filters with 50 and 25 transmissivity, respectively, have been mounted in free positions of the interference filter wheel in front of the detector. Furthermore, the gain of the diode amplifier can now be reduced by a factor of ten, allowing an up to 40 fold overall signal reduction, in addition to the input attenuator of the transient recorder. Through these modifications it is now possible to measure the strongest occuring backscatter signals without overloading. The achromatic lens for the beam expanding telescope of the neodymium laser has just been delivered by the optical company and will be installed in the near future. The exchange of the telescopes is then no longer required.
- Atmospheric Physics