Dr. Takashi Fujii
Dr. Tetsuo Fukuchi, Dr. Nianwen Cao, Mr. Takuya Nayuki, Dr. Naohiko
Goto, Prof. Dr. Koshichi Nemoto
Electrical Physics Department
Central Research Institute of Electric Power Industry (CRIEPI)
2-11-1, Iwado Kita, Komae-shi, Tokyo 201-8511 Japan
WEB SITE: http://
November 8, 2001
LIDAR LOCATION (CITY, COUNTRY, LAT., LONG.):
Komae City, Tokyo, Japan, 35 deg 38 min N, 139 deg 35 min E (about
20 km west of downtown Tokyo)
PARAMETER(S) OR CONSTITUENT(S) MEASURED:
Now: SO2, NO2, O3, Hg (by DIAL), Aerosol extinction and backscatter
coefficients (by Mie lidar)
Near future: Water vapor, O3, (Temperature?) (by Raman lidar)
RESEARCH OBJECTIVES AND SPONSOR:
Research objectives: To investigate generation, transportation
and reaction mechanisms of air pollutants
Sponsor: Electric power industries in Japan
DIAL, Mie lidar, Raman lidar
- SO2: 1000-4000 m
- NO2: 1000-2000 m (day time), 1000-3000 m (night time)
- O3: 1000-4000 m
- Hg: 400-700 m (under construction)
SO2, NO2 and O3 measurements in shorter range (>400m) may be
- SO2: <0.3 ppm?m (Typical range resolution: 150-300 m)
- NO2: <1 ppm?m (Typical range resolution: 150-300 m)
- O3: <0.5 ppm?m (Typical range resolution: 150-300 m)
FREQ. OF MEASUREMENT (TYPICALLY):
1-2 weeks in a month
MEASUREMENT TIMES (TYPICALLY):
5-10 minute integration for 1 profile, continuous acquisition
of profiles for up to 24 hours
LASER TYPE AND WAVELENGTH (s):
Nd: YAG laser (HOYA Continuum Powerlite 8010) pumped dye lasers
(HOYA Continuum ND6000)
Wavelength: 250-900 nm
250nm (for Hg): 2 mJ
285-290nm (for O3): 15-25 mJ
300nm (for SO2): 30 mJ
450nm (for NO2): 20 mJ
532nm (for aerosol): 50 mJ
PULSE REPETITION RATE:
RECEIVER SIZE AND CONFIGURATION:
Primary-mirror diameter: 500 mm
Photomultiplier tube (Hamamatsu R3896)
Digitized PMT signals are averaged over an integration time for
each wavelength and treated as return signals with 7.5m range
resolution. Vertical profiles of the target substances' concentrations
and aerosol extinction and backscatter coefficients are obtained
by using the following manner: (1) subtract the background level
obtained from the return signal before the firing of the laser,
(2) average all signals over an appropriate number of time bins,
for example, 40 bins for a range resolution of 300 m, and (3)
calculate the substances' concentration profiles by use of DIAL
equation, and aerosol extinction and backscatter coefficients
by the Klett or Fernald method.
Transient digitizer (GaGe CS1012), 12 bits, 20 MHz
Personal computer, Windows NT
PLATFORM (if applicable):
PUBLICATIONS (5 recent and/or significant):
1. T. Fujii, T. Fukuchi, N. Cao, K. Nemoto, and N. Takeuchi, "Trace
atmospheric SO2 measurement by multiwavelength curvefitting and
wavelength optimized dual differential absorption lidar,"
to be published in Appl. Opt. 43, No. 3, January (2002).
2. N. Cao, T. Fujii, T. Fukuchi, N. Goto, K. Nemoto, and N. Takeuchi,
"Estimation of DIAL measurement error for NO2 profiling in
the lower troposphere," to be published in Opt. Eng. 40,
No. 12, December (2001).
3. T. Fukuchi, T. Fujii, N. Cao, K. Nemoto, and N. Takeuchi, "Tropospheric
O3 measurement by simultaneous differential absorption lidar and
null profiling and comparison with sonde measurement," Opt.
Eng. 40, 1944-1949 (2001).
4. T. Fujii, T. Fukuchi, N. Goto, K. Nemoto, and N. Takeuchi,
"Dual differential absorption lidar for the measurement of
atmospheric SO2 of the order of parts in 109," Appl. Opt.
40, 949-956 (2001).
5. T. Fukuchi, T. Fujii, N. Goto, K. Nemoto, and N. Takeuchi,
"Evaluation of differential absorption lidar (DIAL) measurement
error by simultaneous DIAL and null profiling," Opt. Eng.
40, 392-397 (2001).
Our transmitter is composed of two dye lasers each of which can
emit two wavelengths on alternate pulses, and the receiver has
two detector channels. Therefore, the system can simultaneously
measure two pollutants, e.g. O3 and NO2. The system is also capable
of multiwavelength (3 or 4 wavelengths) measurement of one pollutant,
e.g. trace SO2, when higher sensitivity than conventional 2 wavelengths
DIAL is needed. Raman lidar is under preparation, and will be
ready in spring 2002.