10 ns at 532.2 nm is operated at a repetition rate 50 Hz with
an average pulse energy of 300 mJ. The lidar functions in cirrus
mode between 100 - 150 nights per year. Previous: Introduction Next: Analysis Up: Ext. Abst.
Instrumentation
The Rayleigh/Mie lidar at OHP makes measurements during the night
throughout the year. OHP is situated at 43.9 ° N, 5.7 ° E and
at 684 m altitude. We give an overview of the instrumentation
here; details can be found elsewhere [Keckhut et al., 1993,Hauchecorne et al., 1992]. A doubled Nd-YAG laser which emits a light pulse of 10 ns at 532.2 nm is operated at a repetition rate 50 Hz with
an average pulse energy of 300 mJ. The lidar functions in cirrus
mode between 100 - 150 nights per year.
The OHP lidar has an extensive altitude range (1 - 80 km), but
the description of the detection system given here is limited
to that which has been optimized for the UT/LS. The receiving
telescope has an adjustable diaphragm that allows a maximum diameter
of 20 cm. The altitude range for this telescope is between 1 and
25 km. The photon counting system has a 0.5 ms bin width corresponding
to an altitude resolution of 75 m; the received backscatter signal
is averaged over 160 seconds intervals. The lidar is operated
in semi-automatic mode (i.e., signal collection is stopped only
if precipitation occurs or with the onset of dawn). A typical
measurement period is 6 hours. Presently the OHP lidar is not
equipped with a polarizing detector, thus no information about
the size or phase of the aerosols is obtained. Atmospheric temperature
measurements are taken from high-resolution (Vaisala RS80) radiosondes
launched from Nîmes ( 120 km east of OHP).