Wind Lidar Developments and Measurements at NICT

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Wind Lidar Developments and Measurements at
NICT Kohei Mizutani, Toshikazu Itabe, Shoken
Ishii, Tetsuo Aoki, Yasuhiro Murayama, Hironori
Iwai National Institute of Information and
Communications Technology Kazuhiro Asai, Atsushi
Sato Toshoku Institute of Technology Hirotake
Fukuoka Central Research Laboratory, Hamamatsu
Photonics K.K. Takayoshi Ishikawa Nippon Aleph
Co.
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Projects on 2mm Coherent Lidar in new plan from
2006.4

• CO2 DIAL/Wind system
• Ground based system slave oscillator
  100-150mJ at 10-20pps
• Air-borne system slave oscillator 50-100mJ
  at 20-30pps
• 2) Sensing Network
• Test observation system Wind Tracer
  Scanner
• New System slave oscillator 50-100mJ at
  20-30pps
• LD pump , conductive-cooled, 2mm
  solid-state laser is an important part of newly
  developing systems

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CO2 DIAL/Wind system
Laser Oscillator for airborne DIAL/Wind
lidar compact high efficiency conductive-coo
led LD-pump moderate output
Laser Oscillator for Ground Based DIAL/Wind
lidar high efficiencyconductive-cooledLD-pump
relatively high power
50-100mJ at 20-30pps
100-150mJ at 10-20pps
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Ground Based CO2 DIAL/Wind System
HWP

AOM

(105MHz)

AO
-
QSW

HWP

PZT
Resonance Detector

POL
(???????)




Transmitting
PMF


(???)


PMF

Return
3dB

-
Coupler
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Ground Based CO2 DIAL/Wind System
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Pumping configuration
Pump absorption efficiency 0.774
Composite Tm(4),Ho(0.4)YLF rodSide pump
configuration7-segments sink28 package
LDsimilar to the side pump amp of the sub-scale
laser
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LD pump conductive-cooled Tm,HoYLF laser
Long pulse characteristicsin a resonator of 6.2m
Normal out
more repetitiondevelopment of compact laser
for air-borne system
Repetition 10HzCoolant temp -85C
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Characteristic of laser pulse
Output 15mJ
Pulse shape
Spectrum of beat signal
Laser pulse shape and beat signal
Gaussian shape of the pulse Fourier transform
limit of line width(FWHM)?f Pulse wdth(FWHM)?t
?f 0.441/?t ?f 0.89MHz
Experimentally ?f 1MHz
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CO2 DIAL/Wind System

• Ground based CO2 DIAL/WIND 2mm lidar system is
  built up on an optical table.
• LD pump and conductive cooled slave Tm,HoYLF
  oscillator of 100-150mJ at 10-20pps has been
  developed.
• Receiver optics will be completed near future.
• Data processing system will be prepared soon.
• Development of air-borne (mobile) DIAL/WIND lidar
  system is expected.
• LD pump and conductive-cooled lasers of 50-100mJ
  at 20-30pps will be developed for air-borne
  (mobile) system.

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Sensing Network Project The atmosphere over the
urban area of Tokyo will be observed by Wind
Profiler, Doppler lidar,
output 7mJrepetition 100HzW.L. 2.012µm
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NICT ENRI lidar
Partly from Iwai et al. in this conference
NICT lidar
ENRI lidar
rooftop of ENRI Iwanuma Branch
Transceiver unit Mitsubishi Electric
Corp. Scanner control data processing system
Mitsubishi Electric Corp. wavelength 1.54
µm pulse repetition frequency 4000 Hz accumulated
shot number 500 range resolution 29.9 m minimum
range 80.0 mmaximum range 2472.0 m scan
rate 6.0 deg/sec
Transceiver unit Coherent Technologies
Inc. Scanner control data processing system
NICT wavelength 2.012 µm pulse repetition
frequency 100 Hz accumulated shot
number 500 range resolution 180 m minimum
range 630 m maximum range 10 km scan
rate 0.2 deg/sec
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Installation site
NICT lidar
Runway (3000m)
RWY27
Terminal building
MID
1.7km
RWY09
Temperature and Dew point sensor
ENRI lidar
Pacific Ocean
Wind speed and direction sensors
Surface meteorological sensors of Sendai
Aviation Weather Station
Temperature and Dew point sensor
14th Coherent Laser Radar Conference, Snowmass,
Colorado, 10 July 2007
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NICT lidar
PPI (Sendai airport, 8/24/06 33905-35531
UT) (AZ0-360, 2 degree step, EL1 degree)
Shoreline
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Horizontal wind distribution by Dual Doppler
lidar observation
NICT lidar
Result of dual Doppler lidar observation
PPI Scan
ENRI lidar(?3????)
?
?(??)
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Vertical profiles of horizontal velocity vectors
from RHI scan
The data is used to compare with Down Scaling
Simulation System.
Synoptic flow return flow? (Northwesterly flow)
weak southerly to westerly flow
weak southwesterly flow
Sea-breeze layer(Southeasterly flow)
Time (JST)
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two-axes scanner
We need more power!
Future 50-100mJ at 30pps
Now 7mJ at 100pps
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Required characteristics for the lasers in the
sensing network project.
slave oscillator 50-100mJ at 30pps or
more reasonable cost (rod, LD, .)moderate
output moderate repetitionRod candidate
Tm,HoYLF, Tm,HoLLF, Tm,HoGdVO4
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Simulation of 4mmf Tm(4),Ho(0.4)YLF rod for
side pumping from three directions
Pump absorption efficiency 0.793
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• Pumping head for F4mm, L44mm Tm,HoYLF rod
• 12 LD packages
• Rod cooling down to -80C in vacuum container
• LD controlled to about 20C in vacuum container

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Long pulse experiments Multi-mode Fabry-Perot
type Rod temperature 80C
New pumping head seems to be suitable for the
project.
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Lidar systems for the sensing network projects

• Test observations by single and dual Doppler
  lidars are made with small output systems.
• These observations showed the possibility of
  coherent Doppler liar in the Sensing Network
  Project.
• We need Doppler lidar systems with moderate
  output laser.
• Slave oscillator of 50-100mJ at 30pps or more
  will be developed.
• One type of pumping head showed good
  characteristic in long pulse experiment.
• The new pumping head will be also used in the
  mobile CO2 DIAL/WIND lidar system.
• Technical developments of these system will be
  important for future wind, CO2 and H2O(DIAL)
  measurements with space borne 2mm coherent lidar.