Geoscience Reference
In-Depth Information
Table 1. USTC lidar parameters.
Transmitter
Nd:YAG
Dye laser
Wavelength (nm)
532
589
Pulse energy (mJ)
550
50 (typ.)
Line width (cm
−
1
)
1
0.05
Pulse width (ns)
6
6
Repetition frequency (Hz)
20
20
Divergence (mrad)
0.5
0.5
Receive-telescope
Type
Cassegrain
Aperture (mm)
1000
FOV (mrad)
0.2-2
Receiver-filter
Wavelength (nm)
532
589.0
Bandwidth (nm)
1.0
0.5
Transmission
60%
70%
2. Lidar System Configuration
A Mie-Rayleigh-Sodium fluorescence lidar has been assembled, tested
and deployed to the University of Science and Technology of China
(USTC) at Hefei, China in December 2005. The transmitter consists of
a Nd-YAG laser at 532 nm and a Dye laser at 589 nm. The receiver is a 1 m
diameter telescope. Parameters in detail are given in Table 1. The system
has three channels which are used for different atmospheric parameters
detecting, namely, sodium density, atmospheric density and temperature
and aerosol extinction. Auto-align system is also employed to improve the
system's automation. Two wavelength calibration systems can make sure
the wavelength of dye laser output is near to the location of the maximum
eciency of sodium excitation.
3. Preliminary Experimental Results
3.1
. Na layer observation
From December 2005 to April 2007, 53 night observations were obtained.
Most of the observations cover the period of 20:00LT-04:30LT. The raw
data consists of a series of photon counts corresponding to consecutive
range bins. Each profile has an integration time of 4 min with a vertical
resolution of 75 m.
