Lidar (Laser Radar) Observation by National Institute for Environmental Studies

Period: 2006/10/16-2006/12/10

Laser: Nd:YAG
Wavelength: 532 nm (with depolarization measurement), 1064 nm
Laser power: 50 mJ/pulse
Pulse repetition: 10 Hz
Detector: PMT(532) / APD(1064)
Digitizer: 12 bit ADC

Temporal resolution: 5 minutes
Vertical resolution: 6 m
Range: 0 - 18 km

Data file format:
3 files are prepared for each day. YYMMDD indicates date in UTC.
YYMMDD_532abc.txt ---- Attenuated backscatter coefficient at 532 nm
YYMMDD_532dep.txt ---- Observed depolarization ratio at 532 nm
YYMMDD_1064abc.txt ---- Attenuated backscatter coefficient at 1064 nm

Each file contains 288 lines. The 1st one corresponds to 00:00 UTC, the
2nd to 00:05, the 3rd to 00:10, .... the last (96th) to 23:55.

Each line consists of 3000 values. The 1st one corresponds to the
value at 6 m height above the lidar system on Mirai upper deck.
The 2nd to 12 m, ..., the last (3000th) to 18000 m.

Unit:
*abc.txt --- /m/sr
*dep.txt --- (no dimension)

Attenuated backscatter coefficient is proportional to the backscatter
coefficient (by molecular and particle) of the airmass, but the factor
of two-way transmittance (exp[-2 * Tau(optical thickness between lidar
and the airmass)]) is not compensated.

Depolarization ratio is the ratio between the perpendicular component
of the signal and the parallel component. Not the ratio between
perp. and total.

High time-resolution (10 seconds) data are also available from NIES.

Contact: shimizua(at)nies.go.jp