Probing the atmosphere - new radar & lidar technologies for remote sensing of atmosphere
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Transcript of Probing the atmosphere - new radar & lidar technologies for remote sensing of atmosphere
RADAR & LIDAR
Systems and
Applications
26 November, 2015
MMEA Final Seminar
Ari-Matti Harri (FMI)
Juha Toivonen (TUT)
Jarmo Koistinen (FMI)
Heikki Turtiainen (Vaisala)
Dmitri Moisseev (UH)
Juha Salmivaara (Vaisala)
Development of new remote sensing technologies and applications.
Integration in the MMEA Platform.
2 / 9
Eigenor
Harp Technologies
Lentokuva Oy
Space Systems Finland
Vaisala
(Aerial Oy)
Aalto University
Helsinki University
Finnish Meteorological Institute
Finnish Geodetic Institute
Partners
Lidar for wind energy
Site assessmentmeasurements
+Lowered costs
+Data from several heights
Operational wind data for turbine control
+ Longer lifespan of turbines
+ Increased output
+ Reduced turbine materialcosts
• Novel DFB laser with narrow 100 kHz linewidth was built
• High-power version with semiconductor amplifier was constructed
• Linewidth and wavelength stability the lasers have been characterized
DFB laser
structure
Cost effective lasers for lidar
J. Telkkälä, J. Viheriälä, A. Aho, P. Melanen, J. Karinen, M. Dumitrescu, and
M. Guina, Electronics Letters 47, pp. 400-401 (2011).
< 400 mW
Wind lidar measurements
• Optical fiber based wind lidar
demonstration has been constructed
and tested in laboratory conditions
• Focus on developing cost effective
wind lidar technology
• Evaluation of the commercial HALO
Doppler wind lidar in Nordic winter
conditions
• Wind lidar measurements compared
against traditional wind measurements
11/25/201
5[Name]9
Conventional Lidar with one
wavelength
(for example a ceilometer)
DIAL = Differential Absorption
LIDAR with two wavelengths
atmospheric
backscatter
λ1
λ1
"offline"
λ2
"online"
atmospheric
backscatter
2015-09
Retrieving Vertical Humidity:
MMEA DIAL - Differential Absorption LIDAR
An example of comparison with
Vaisala DIAL and a sounding – the results
(blue dots sounding, black dots Vaisala
DIAL) indicate good agreement up to the
top of the boundary layer
Vaisala DIAL
Reference DIAL
Rotational Raman
LIDAR
Performing a sonde launch at a test
site in Germany during a test campaign
Comparison with Vaisala DIAL and a sounding – the results
(blue dots sounding, black dots Vaisala DIAL) indicate good
agreement up to the BL top
WV DIAL –Continuously useable& Low cost device
MMEA / VAISALA WV DIAL:
More compact, low cost & field capable
instrument than current research DIALs.
Vaisala WV DIAL humidity profile (black) compared with a radiosonde profile (blue) –
good agreement up to the atmospheric boundary layer top.
Ku-band tests
•Extensive laboratory tests in Aalto (together with
Harp)
•Tx/Rx module meets the specifications
•Transmitter total output power up to 60 W
(adjustable with attenuators), no spurious signals
observed with spectrum analyser
•Receiver gain close to 25 dB,
25.11.2015 16
10,0
15,0
20,0
25,0
30,0
35,0
40,0
13,925 13,935 13,945 13,955 13,965 13,975 13,985 13,995
Gain
[dB
]
Frequency [GHz]
Transmitter - Gain at driver output
0,0
5,0
10,0
15,0
20,0
25,0
30,0
125 135 145 155 165 175
Gain
[dB
]Frequency [MHz]
Receiver gain (channel V)
MMEA Radar Applications
• Triple-PRT processing of polarimetric radar signals
developed for implementations (Eigenor, FMI, UH,
Vaisala)
• Multi-source algorithms for object-oriented meso-scale
nowcasting of thunderstorms developed (FMI, CSU)
• Operational assimilation of radar and lightning data
into the Local Analysis and Prediction System done
(FMI, Vaisala)
• New statistical method (OPT) developed for automatic
classification of radar echoes (FMI)
• Procedures for simultaneous optimal multi-radar
scanning developed (UH, Vaisala, CSU)
• Micro-physically based QPE in wet and dry snowfall
developed (UH, Vaisala, FMI)
Highlight:Triple-PRT available for weather radars
Unambiguous velocity comparisons up to 54 m/s performed
Effects of the new adaptive clutter filtering studied and validated
Utilization of multi-modal Doppler spectra information studied
Triple-PRT book ready
International application tests done and a joint tender submitted
Highlight:Automatic Classification
of Radar Observations (OPT) Manually chosen representative cases for fine-grained classes
Pattern recognition filters
New probability density model providing metric and group operators for data
analysis applying Legendre and Chebychev polynomials
Optimal subspace determination for a given classification task in 60-
dimensional data space
Bird collision demonstration
dBT O(dBT)
G(SQI) P(Birds.arctic)
Affordable innovative systems and applications
New remote sensing instrumentation and obs data
Innovative monitoring and analysis algorithms for
environmental decision-making
Establishment of cooperation
SMLEs & Ops/Res & Univs Triple Helix
Establishment of international cooperation (incl SMEs)
Scientific results documented by peer revieded
publications (~40), tens of scientific conference
presentations and 7 doctoral dissertations.
MMEA RADARS, LIDARS
& Remote Sensing
Technical specifications
25.11.2015 24
Center Frequencies:
Ku-band: 13.96 GHz ± 25 MHz
Ka-band: 33.5 GHz ± 25 MHz
Range resolution: 80 m
Pulse length: variable from 1 µs to 60 µs
Pulse repetition time: 0.3 ms to 1 ms
Minimum operational range: 150 m
Maximum operational range: 30 km
Sensitivity: in clean air -10dBZ at 15km
Doppler velocity resolution: 10m/s
Beam width: 1 degree
Pointing accuracy: 0.2 degree
Peak Power:
Ku-band: 60 W
Ka-band: 20 W
Objectives
•Development and demonstration of high frequency radar system
•Advanced and novel characteristics:•Solid state transmitters
•Transportable
•Three high frequency bands (Ku, Ka and W)
•Platform for research and for application development•Microwave interaction with precipitation and cloud droplets
•Air traffic safety
•Aircraft wake vortices
•Now-casting for wind farms – combined use with lidars
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Ku-band roof test
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•Transmitted signal:
•Linear FM, one 50 s pulse
•Clear sky, but one condense mark from a high-
flying plane
• Oscilloscope is showing the switch control
pulse (yellow) and received calibration signal
through internal connection (blue)
Ridgeline eDAQ
Digital receiver & Arbitrary waveform generator
•Software development made by SSF
•AWG waveforms selectable:•Linear FM
•Non-Linear FM
•PSK (5, 7, 11 or 13 bits)
•Fixed Frequency-Fixed Amplitude
•Pulse length selectable
•One or two pulses
25.11.2015 27
Ku-band roof test
25.11.2015 28
•Saved data was analysed with
Eigenor software tool•Eigenor SW compatible with the data format
•received complex echoes shown: real part (blue), imaginary (red)
•Pulse lenght 50 s => first 500
range gates: transmitted pulse via
internal ”calibration” path
•eDAQ software related issues
was identified (mainly related to
switching times) => software
updating on-going
Conclusions
WP3 Task 2 (Ku/Ka/W radar) development results:
•Complete modular radar infrastructure for mobile (W-Tx/Rx missing), solid state -based multi-band radar allowing for inclusion of W-band Tx/Rx and additional bands•First field tests performed•Technology level leap in Ku/Ka/W radar field for Finnish SMEs•Establishment of international co-operation (Finnish SMEs)•Cooperation scheme established for SMEs, larger companies and scientific organizations•Applications for a mobile Ku/Ka/W -radar surveyed (scientific & operational)
•Ka-band radar development work continues, HARP is using their own resources in order to integrate the Tx/Rx module.
25.11.2015 29
WV DIAL target applications
Target applications and motivations
Data assimilation • Improving weather forecast accuracy in general
• Prediction of convection => early warning for thunderstorm &
tornado
Verification,
calibration
• Verifying, comparing and monitoring forecast systems
Monitoring • Understanding of Earth’s water cycle and long-term climate
change
Process studies • Understanding of cloud and precipitation systems, water vapor
transport and exchange processes
Summary of WP3.3 LIDAR
•Techniques demonstrated for wind lidar: heterodyne &
enhanced self-mixing
•Laser source development on fiber amplifiers and
semiconductor lasers and amplifiers
•Humidity lidar performance developed further and
compared against a Raman LIDAR
25.11.2015 [email protected]